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NASA: Assessments of Major Projects
Government Accountability Office
May 1, 2018

ЦитироватьULA Delta II Booster Arrives for ICESat-2 Mission

Bob Granath (https://blogs.nasa.gov/icesat2/author/rgranath/)
Posted May 22, 2018 at 4:55 pm

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At NASA's Building 836, the Spacecraft Labs Telemetry Station at Vandenberg Air Force Base in California, a United Launch Alliance (ULA) Delta II booster is removed from its shipping container on Monday, April 16, 2018. Once it was offloaded, preliminary checkouts and preflight processing began in preparation for the agency's Ice, Cloud and land Elevation Satellite-2, or ICESat-2.

Liftoff from Space Launch Complex-2 at Vandenberg is scheduled for Sept. 12, 2018, and will be the last for the venerable Delta II rocket. The spacecraft, which is being built and tested by Orbital ATK in Gilbert, Arizona, will carry a single instrument called the Advanced Topographic Laser Altimeter System, or ATLAS. The ATLAS instrument is being built and tested at NASA's Goddard Space Flight Center in Greenbelt Maryland.

Once in orbit, the satellite is designed to measure the height of a changing Earth, one laser pulse at a time, 10,000 laser pulses a second. ICESat-2 will help scientists investigate why, and how much, Earth's frozen and icy areas, called the cryosphere, are changing.

Photo credit: USAF 30th Space Wing/Vanessa Valentine

Цитировать(https://img.novosti-kosmonavtiki.ru/186371.jpg)pat o. ‏ @spacepat_o (https://twitter.com/spacepat_o) 4 ч.4 часа назад (https://twitter.com/spacepat_o/status/999330603043557377)

"A @ulalaunch (https://twitter.com/ulalaunch) #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) booster arrives at @NASA (https://twitter.com/NASA)'s Building 836, the Spacecraft Labs Telemetry Station at Vandenberg Air Force Base in California." This booster will launch the #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) mission on Sept. 12, 2018. Photos: NASA/Randy Beaudoin & USAF 30th Space Wing/Vanessa Val

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Цитировать(https://img.novosti-kosmonavtiki.ru/186371.jpg)pat o. ‏ @spacepat_o (https://twitter.com/spacepat_o) 17 ч. назад (https://twitter.com/spacepat_o/status/1001486721685573633)

The final #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) booster being transported to SLC-2 at Vandenberg Air Force Base in California. This booster will be used to launch the ICESat-2 mission for NASA on September 12, 2018. Credit: NASA/Randy Beaudoin

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Цитировать(https://img.novosti-kosmonavtiki.ru/185344.jpg)NASA_LSP‏Подлинная учетная запись @NASA_LSP (https://twitter.com/NASA_LSP) 52 мин. назад (https://twitter.com/NASA_LSP/status/1001821309972762624)

In @NASA (https://twitter.com/NASA)'s Building 8337 at @30thSpaceWing (https://twitter.com/30thSpaceWing), technicians and engineers cleaned and took samples from the payload fairing that will protect @NASA_ICESat2 (https://twitter.com/NASA_ICESat2) (https://img.novosti-kosmonavtiki.ru/125535.png) during launch. Liftoff atop a @ulalaunch (https://twitter.com/ulalaunch) Delta II (https://img.novosti-kosmonavtiki.ru/125513.png) is scheduled for Sept. 12, 2018. More photos: https://go.nasa.gov/2LFuioJ  (https://t.co/7TBz9PsGse)

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Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 42 мин. назад (https://twitter.com/ulalaunch/status/1004777143744819200)

Heads up! The ULA #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) rocket slated to launch NASA's @ICESat (https://twitter.com/IceSat)-2 mission is vertical on the launch pad at Vandenberg AFB! See you in Sept as we launch this important Earth science mission – the final for the storied #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash). Photos: @NASA_LSP (https://twitter.com/NASA_LSP) @NASA_Edge (https://twitter.com/NASA_EDGE)

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ЦитироватьСтарый пишет:
Дельта-2 жива старушка!
Сколько их ещё в запасе?

ЦитироватьThe final #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) booster ...

ЦитироватьNASA's ICESat-2 Spacecraft Arrives at Vandenberg Air Force Base

Linda Herridge (https://blogs.nasa.gov/icesat2/author/lherridg/)
Posted Jun 13, 2018 at 3:34 pm

(https://img.novosti-kosmonavtiki.ru/130824.jpg)
NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) arrives in its shipping container aboard a heavy transport truck on June 12, 2018, at Vandenberg Air Force Base in California. Photo credit: USAF 30th Space Wing/Mark Mackley

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, arrived at Vandenberg Air Force Base in California on Tuesday, June 12, fr om the Northrop Grumman facility in Gilbert, Arizona. The satellite will be offloaded in its shipping container from the heavy transport truck and moved into the Astrotech Space Operations facility wh ere it will be processed and prepared for its mission.

ICESat-2 is scheduled to launch Sept. 12, 2018, on the final United Launch Alliance Delta II rocket, from Space Launch Complex-2 at Vandenberg.

Once in orbit, the satellite is designed to measure the height of a changing Earth, one laser pulse at a time, 10,000 laser pulses a second. ICESat-2 will help scientists investigate why, and how much, Earth's frozen and icy areas, called the cryosphere, are changing.

Спойлер

NASA's Goddard Space Flight Center manages development of the ICESat-2 mission, including mission systems engineering and mission operations on behalf of the agency's Earth Science Division. The ICESat-2 spacecraft was built and tested by Northrop Grumman in Gilbert, Arizona. The satellite will carry a single instrument called the Advanced Topographic Laser Altimeter System, or ATLAS, built and tested at NASA's Goddard Space Flight Center in Greenbelt, Maryland. United Launch Alliance of Centennial, Colorado, is providing the Atlas V launch service. NASA's Launch Services Program, based at Kennedy Space Center in Florida, is responsible for launch service acquisition, integration, analysis, and launch management.

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ЦитироватьJune 13, 2018

NASA's ICESat-2 Arrives at Launch Site

NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) arrived at Vandenberg Air Force Base in California on Tuesday, June 12, three months before its scheduled launch on United Launch Alliance's final Delta II rocket. After launch, slated for Sept. 12, 2018, ICESat-2 will use a laser instrument to measure the height of Earth's surface in unprecedented detail.

Спойлер

(https://img.novosti-kosmonavtiki.ru/208133.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/vafbarrival1small.jpg)
A truck carrying the ICESat-2 satellite, packed safely in a specialized shipping carrier, arrives at Vandenberg Air Force Base near Lompoc, California, on June 12, 2018. ICESat-2 is scheduled to launch fr om Vandenberg this fall to measure the height of ice and other surfaces across the globe.
Credits: NASA

ICESat-2's sole instrument, called the Advanced Topographic Laser Altimeter System (ATLAS), was assembled and tested at NASA's Goddard Space Flight Center in Greenbelt, Maryland. ATLAS was then trucked to a Northrop Grumman facility in Arizona, where it was integrated with the ICESat-2 spacecraft – which provides navigation, power, communications and more.

https://www.youtube.com/watch?v=OQg5ov6zths (https://www.youtube.com/watch?v=OQg5ov6zths)
(video (https://www.youtube.com/watch?v=OQg5ov6zths) 1:55)
ICESat-2 will measure the height of Earth, with a focus on monitoring change in the planet's icy poles.
Credits: NASA/Ryan Fitzgibbons

The final leg of ICESat-2's ground-based journey started Monday morning, as crews loaded the satellite into a specialized truck and drove about 600 miles to Vandenberg, near Lompoc, California. The team monitored the satellite's slight movements and temperatures along the route, keeping it in the low 70s as outside temperatures exceeded 100 degrees Fahrenheit (38 degrees Celsius). ICESat-2 arrived midday Tuesday.

Once the satellite is unpacked in a cleanroom operated by Astrotech Corp. at Vandenberg, the ICESat-2 team will conduct a few tests, including firing the lasers, to ensure nothing was disturbed during the shipping process. The completed satellite observatory – with its instrument, spacecraft bus and solar arrays – was tested extensively in Arizona.

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The ICESat-2 satellite sits in a cleanroom at Northrop Grumman in Gilbert, Arizona, where the instrument and spacecraft were integrated and tested prior to its shipping to California.
Credits: Northrop Grumman

"This year, we've gone through final testing including acoustics testing, comprehensive performance testing of the satellite with the two flight lasers, installed the solar array, conducted a solar array deployment and performed an ATLAS door deploy – we know everything is working well," said Joy Henegar-Leon, ICESat-2's Observatory and Ground Systems Manager. The team also conducted a dry run of the post-launch procedures that power up the spacecraft and instrument, and configure the satellite for science data collection.

After launch, the fast-firing laser and sensitive detectors aboard ICESat-2 will allow it to collect precise measurements of Earth's height. The mission is designed to focus on changes in the ice sheets and sea ice in Antarctica and the Arctic, wh ere warming temperatures are having dramatic effects. The satellite will track the changes in these polar regions and around the globe.

ICESat-2 will launch on United Launch Alliance's final Delta II rocket, which is undergoing final assembly at Vandenberg.

For more information on ICESat-2, visit: https://icesat-2.gsfc.nasa.gov/

For updates on ICESat-2 and its Delta II at Vandenberg, visit: https://blogs.nasa.gov/icesat2/

For more information about NASA launches, visit: https://www.nasa.gov/centers/kennedy/launchingrockets/index.html

By Kate Ramsayer (mailto:kate.ramsayer@nasa.gov?subject=Re%3A%20Ice)
NASA's Goddard Space Flight Center (http://www.nasa.gov/goddard), Greenbelt, Md. 

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Last Updated: June 13, 2018
Editor: Sara Blumberg

ЦитироватьDelta II Comes Together Ahead of ICESat-2 Launch

Anna Heiney (https://blogs.nasa.gov/icesat2/author/aheiney/)
Posted Jun 27, 2018 at 4:13 pm

(https://img.novosti-kosmonavtiki.ru/130823.jpg) (https://blogs.nasa.gov/icesat2/wp-content/uploads/sites/283/2018/06/DeltaII7420-10_Rev4.jpg)
This expanded-view graphic depicts the components of the United Launch Alliance Delta II rocket that will launch NASA's ICESat-2 spacecraft. Image credit: United Launch Alliance

The United Launch Alliance Delta II rocket slated to launch NASA's Ice, Cloud and land Elevation Satellite-2 (https://www.nasa.gov/icesat2/), or ICESat-2, has made significant progress toward liftoff, planned for Sept. 12. Prelaunch preparations are well underway at Vandenberg Air Force Base in California, where the rocket is coming together at Space Launch Complex 2. Earlier this month the booster, or first stage, was lifted into place in the complex's mobile service tower, followed by installation of the rocket's four solid rocket motors, as well as the interstage, a connector that adjoins the first and second stages. The rocket's second stage was lifted and installed atop the booster on Thursday, June 21.

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(https://img.novosti-kosmonavtiki.ru/130825.jpg) (https://blogs.nasa.gov/icesat2/wp-content/uploads/sites/283/2018/06/ICESat2_DeltaII_Stage1_Lift.jpg)
The United Launch Alliance Delta II first stage is lifted up in the mobile service tower at Space Launch Complex 2 at Vandenberg Air Force Base in California. Photo credit: USAF 30th Space Wing/Pedro Carrillo

The ICESat-2 spacecraft arrived at Vandenberg on June 12 and is undergoing its own processing activities inside the Astrotech Space Operations facility.

NASA's Goddard Space Flight Center manages development of the ICESat-2 mission, including mission systems engineering and mission operations on behalf of the agency's Earth Science Division. The ICESat-2 spacecraft was built and tested by Northrop Grumman in Gilbert, Arizona. The satellite will carry a single instrument called the Advanced Topographic Laser Altimeter System, or ATLAS, built and tested at NASA's Goddard Space Flight Center in Greenbelt, Maryland. United Launch Alliance of Centennial, Colorado, is providing the Delta II launch service. NASA's Launch Services Program, based at Kennedy Space Center in Florida, is responsible for launch service acquisition, integration, analysis, and launch management.

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ЦитироватьULA (https://twitter.com/ulalaunch) ретвитнул(а)

(https://img.novosti-kosmonavtiki.ru/186371.jpg)pat o.‏ @spacepat_o (https://twitter.com/spacepat_o) 2 ч. назад (https://twitter.com/spacepat_o/status/1014115608735121408)

The @ulalaunch (https://twitter.com/ulalaunch) #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) first stage was raised vertical and moved into the Mobile Service Tower at SLC-2 at Vandenberg AFB on June 8 for its final flight. The rocket will launch @NASA (https://twitter.com/NASA)'s #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) spacecraft to Low Earth Orbit on Sept 12. (https://img.novosti-kosmonavtiki.ru/125427.png): @30thSpaceWing (https://twitter.com/30thSpaceWing) / Pedro Carri

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ЦитироватьJuly 6, 2018

Ice, Ice Baby! Experience the Launch of NASA's ICESat-2, and the Final Delta II Rocket

Ice, space lasers, penguins and a workhorse rocket's last liftoff – it's the stuff great tweets are made of.

NASA is inviting social media users to apply for credentials to attend the launch of the agency's Ice, Cloud and Land Elevation Satellite-2, or ICESat-2, aboard United Launch Alliance's Delta II rocket. Launch from Vandenberg Airforce Base near Lompoc, California is targeted for no earlier than Sept. 12.

​ICESat-2 will measure the height of our home planet, with a focus on tracking changes to the ice sheets, glaciers and sea ice of Earth's polar regions. The satellite's novel laser instrument measures height by timing individual photons of light to the billionth of a second, which will allow scientists to precisely measure change, including the impacts of a warming climate.

The satellite launches on ULA's last Delta II rocket, which has previously carried NASA satellites and spacecraft including the Spirit and Opportunity Mars rovers, Landsat 7 and, in 2003, the original ICESat.
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Last Updated: July 6, 2018
Editor: Kindra Thomas

ЦитироватьJuly 9, 2018

ICESat-2 Lasers Pass Final Ground Test

The next time lasers fire fr om NASA's Ice, Cloud, and land Elevation Satellite-2, or ICESat-2, the spacecraft will be orbiting hundreds of miles above Earth and beginning its mission to monitor changes in ice sheets, glaciers and sea ice.

(https://img.novosti-kosmonavtiki.ru/207774.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat_test.jpg)
ICESat-2 is uncrated inside the airlock of the Astrotech processing facility at Vandenberg Air Force Base in California, prior to a successful series of tests of the satellite and its instrument.
Credits: USAF 30th Space Wing/Vanessa Valentine

On June 23, ICESat-2 engineers at Vandenberg Air Force Base in California successfully finished the final ground-based test of the lasers, which are part of the satellite's sole instrument called the Advanced Topographic Laser Altimeter System (ATLAS). ICESat-2 is scheduled to launch from Vandenberg on Sept. 12, 2018.

ATLAS was built at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and trucked to a Northrop Grumman facility in Arizona wh ere it was integrated with the spacecraft bus that provides power, navigation and communications. The completed satellite arrived at Vandenberg on June 12.

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(https://img.novosti-kosmonavtiki.ru/208375.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat_2.jpg)
The second stage of the United Launch Alliance Delta II rocket is lifted high up at the Vertical Integration Facility, at left, at Space Launch Complex 2 on June 21, 2018, at Vandenberg Air Force Base in California. The second stage will be attached to the top of the booster, or first stage of the rocket, which is being moved out of the Mobile Service Tower, at right.
Credits: NASA/Randy Beaudoin

In the Astrotech Space Operations cleanroom at Vandenberg, the ICESat-2 team tested both the spacecraft and instrument. NASA ICESat-2 launch integration manager John Satrom reports that the data from these tests have been reviewed and everything is normal.

Meanwhile at Vandenberg's Space Launch Complex 2 along the Pacific coast, crews from United Launch Alliance are assembling the Delta II rocket that will launch ICESat-2 into space. The first and second stage, the interstage connecting them, and four solid rocket motors are in place. The ICESat-2 mission will mark the final launch for the Delta II, which will then be retired.

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After the successful completion of another round of "aliveness" tests turning on the satellite and instrument at the end of July, the ICESat-2 payload is scheduled to head to the launch pad in late August, according to Satrom.

Last Updated: July 9, 2018
Editor: Sara Blumberg

ЦитироватьNASA Invites Media to View Launch of ICESat-2 from West Coast

Linda Herridge (https://blogs.nasa.gov/icesat2/author/lherridg/)
Posted Aug 7, 2018 at 5:02 pm

(https://img.novosti-kosmonavtiki.ru/130826.jpg)
The ICESat-2 mission will measure the changing height of Earth's glaciers, ice sheets and sea ice, one laser pulse at a time, 10,000 laster pulses per second. Image credit: NASA

Media accreditation is open for the launch of NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2 (https://www.nasa.gov/content/goddard/icesat-2), scheduled for Saturday, Sept. 15, with a 40-minute window opening at 8:46 a.m. EDT (5:46 a.m. PDT). ICESat-2 will provide precise measurements of the changing height of Earth's glaciers, ice sheets and sea ice.

The spacecraft will lift off from Space Launch Complex 2 at Vandenberg Air Force Base in California on the final launch of a United Launch Alliance Delta II rocket.

Спойлер

...
ICESat-2 will measure the height of our changing Earth, one laser pulse at a time, 10,000 laser pulses per second. The satellite will carry a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), which measures the travel times of laser pulses to calculate the distance between the spacecraft and Earth's surface. ICESat-2 will provide scientists with height measurements that create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, forests and more.

NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages development of the ICESat-2 mission, including mission systems engineering and mission operations on behalf of the agency's Earth Science Division. Goddard also built and tested the ATLAS instrument. The ICESat-2 spacecraft was built and tested by Northrop Grumman (http://www.northropgrumman.com/Pages/default.aspx) in Gilbert, Arizona. United Launch Alliance (https://www.ulalaunch.com/) of Centennial, Colorado, is providing the Delta II launch service. NASA's Launch Services Program (https://www.nasa.gov/centers/kennedy/launchingrockets/index.html), based at Kennedy, is responsible for launch service acquisition, integration, analysis and launch management.

For more information about the ICESat-2 mission, visit https://www.nasa.gov/icesat-2.

Join the conversation on social media by following on Twitter at https://twitter.com/NASA_ICE.

Photo and video content for ICESat-2 is available at http://images.nasa.gov/.

https://svs.gsfc.nasa.gov/Gallery/icesat2.html

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ЦитироватьPhotos: Final Delta 2 rocket assembled for launch in California
August 16, 2018 (https://spaceflightnow.com/2018/08/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

The step-by-step stacking of United Launch Alliance's final Delta 2 rocket was completed in June at Vandenberg Air Force Base in California for liftoff Sept. 15 with an Earth science satellite for NASA.

Workers at Vandenberg lifted the Delta 2's first stage on its launch mount June 8, then added an interstage connector June 12. Ground crews mated four solid-fueled strap-on boosters in mid-June, and hoisted the Delta 2's second stage into position June 21.

These photos show the pieces of the Delta 2 rocket arriving at Space Launch Complex 2-West at Vandenberg ahead of liftoff Sept. 15 with NASA's ICESat 2 satellite, designed to measure changes in ice sheets, and the height of vegetation, land and ocean surfaces, and clouds from an orbit around 300 miles (500 kilometers) above Earth.

The launch window Sept. 15 opens at 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT).

The ICESat 2 mission will be the 155th and final launch of a Delta 2 rocket since February 1989. Of the 154 Delta 2 flights completed to date, 152 have been successful.

Спойлер

Read our full story (https://spaceflightnow.com/2018/08/16/fueling-test-marks-resumption-of-delta-2-rockets-final-launch-campaign/) for details on the Delta 2 launch campaign. The photos posted below show the Delta 2's launch preparations at Vandenberg Air Force Base.

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The Delta 2 rocket is removed from its shipping container after arriving at Vandenberg Air Force Base. Credit: USAF 30th Space Wing/Vanessa Valentine

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Credit: NASA/Randy Beaudoin

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Credit: NASA/Randy Beaudoin

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Credit: NASA/Randy Beaudoin

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Technicians clean and take samples from one-half of the Delta 2's payload fairing. Credit: NASA/Randy Beaudoin

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The Delta 2's first stage arrives at Space Launch Complex 2-West. Credit: USAF 30th Space Wing/Pedro Carrillo

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The Delta 2's first stage is raised off its transport trailer. Credit: USAF 30th Space Wing/Pedro Carrillo

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The Delta 2 rocket's first stage RS-27A main engine. Credit: USAF 30th Space Wing/Pedro Carrillo

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Credit: USAF 30th Space Wing/Pedro Carrillo

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The Delta 2's first stage is raised into the mobile service tower. Credit: USAF 30th Space Wing/Pedro Carrillo

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The Delta 2's interstage is lifted at Space Launch Complex 2-West. Credit: USAF 30th Space Wing/Mark Mackley

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Credit: USAF 30th Space Wing/Mark Mackley

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The Delta 2's interstage is lowered onto the rocket's first stage. Credit: USAF 30th Space Wing/Mark Mackley

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One of the Delta 2's four solid rocket boosters arrives at the launch pad. Credit: USAF 30th Space Wing/Mark Mackley

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Credit: USAF 30th Space Wing/Mark Mackley

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Technicians position one of the Delta 2's four solid rocket boosters onto the first stage. Credit: USAF 30th Space Wing/Mark Mackley

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Credit: USAF 30th Space Wing/Mark Mackley

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Credit: USAF 30th Space Wing/Mark Mackley

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A member of the Delta 2 team assists in the placement of a solid rocket booster on the first stage of the Delta 2 rocket at Vandenberg Air Force Base on June 15. Credit: USAF 30th Space Wing/Mark Mackley

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Workers prepare the Delta 2's second stage for its attachment to the rocket. Credit: NASA/Randy Beaudoin

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The Delta 2's second stage is raised into the mobile service tower. Credit: NASA/Randy Beaudoin

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Ground crews lift the second stage of a Delta 2 rocket into the mobile gantry at Space Launch Complex 2-West at Vandenberg Air Force Base. The second stage was stacked atop the Delta 2 rocket June 21. Credit: NASA/Randy Beaudoin

(https://img.novosti-kosmonavtiki.ru/144791.jpg)
Credit: NASA/Randy Beaudoin

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ЦитироватьTanking test marks resumption of Delta 2 rocket's final launch campaign
August 16, 2018 (https://spaceflightnow.com/2018/08/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

(https://img.novosti-kosmonavtiki.ru/144790.jpg)
Ground crews lift the second stage of a Delta 2 rocket into the mobile gantry at Space Launch Complex 2-West at Vandenberg Air Force Base. The second stage was stacked atop the Delta 2 rocket June 21. Credit: NASA/Randy Beaudoin

With each day, another milestone passes like clockwork for engineers and technicians preparing a United Launch Alliance Delta 2 rocket for liftoff next month fr om California's Central Coast. With 154 missions in the books — that's a lot for a space launcher — you might be right to say getting a rocket ready to fly is just another day at the office for the Delta 2 team.

But this summer's launch campaign at Vandenberg Air Force Base, overlooking the Pacific Ocean between Los Angeles and San Francisco, is the last for the Delta 2 program after a run of launches spanning more than 29-and-a-half years.

The payload for the last Delta 2 flight is NASA's ICESat 2 satellite, an orbiting platform that will use a laser to chart the melting of ice brought on by climate change.

"In a lot of ways, the Delta 2 launch of ICESat 2 is truly going to be the end of an era," said Tim Dunn, NASA's launch director for the ICESat 2 mission, in a recent interview. "It's a little melancholy, but at the same time what a great history to celebrate."

On Wednesday, controllers loaded super-cold liquid oxygen propellant into the Delta 2's first stage on its launch pad at Vandenberg during a practice countdown — known as a wet dress rehearsal — that exercised ground teams and provided a checkout of the launch vehicle.

The successful wet dress rehearsal came three days after ULA and NASA relocated critical members of the Delta launch team fr om Cape Canaveral to Vandenberg after Sunday's liftoff of a Delta 4-Heavy rocket with the Parker Solar Probe from Florida's Space Coast.

With the practice countdown accomplished, crews at Space Launch Complex 2-West at Vandenberg will ready the Delta 2 rocket for attachment of the ICESat 2 spacecraft next week.

ICESat 2 — short for Ice, Cloud and land Elevation Satellite — arrived at the Vandenberg launch base in June from a Northrop Grumman Innovation Systems factory in Gilbert, Arizona. Since then, the satellite has been fueled with its own supply of maneuvering propellant, and technicians have verified ICESat 2 is ready for liftoff.

Liftoff is scheduled for a launch window opening at 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT) on Sept. 15.

On its final flight, the Delta 2 will be propelled by a kerosene-burning first stage Aerojet Rocketdyne RS-27A main engine, four strap-on solid rocket boosters, and a restartable second stage AJ10-118K engine. The target for the Sept. 15 mission: A roughly circular polar orbit around 300 miles (500 kilometers) above Earth.

Спойлер

(https://img.novosti-kosmonavtiki.ru/144777.jpg)
A technician opens and checks the flight door of ICESat's laser altimeter instrument during pre-launch processing inside an Astrotech clean room at Vandenberg Air Force Base. Credit: USAF 30th Space Wing/Timothy Trenkle

During its planned three-year mission, ICESat 2 will fire a downward-facing on-board laser with 10,000 pulses per second, precisely measuring the time it takes for the laser signals to bounce off Earth's surface and back to the satellite. The measurements will yield information about the height of ice caps, vegetation, land and water surfaces, and clouds.

Scientists will use data from ICESat 2 — a replacement for NASA's ICESat satellite which operated from 2003 until 2009 — to see wh ere ice is melting and flowing, helping quantify and identify the impacts of warming global temperatures.

Once bolted to the adapter cone that will connect it to the Delta 2 second stage, ICESat 2 will be placed in a transport container for the short road trip from the Astrotech payload processing facility to the SLC-2W launch pad. Cranes will hoist the spacecraft — weighing around one-and-a-half tons — into the launch pad's mobile gantry.

The moving service structure will roll back around the Delta 2, allowing workers to install the ICESat 2 spacecraft on the rocket and encapsulate it inside the launcher's composite nose shroud, capping assembly of the 128-foot-tall (39-meter) vehicle. Then comes a sequence of testing to ensure the satellite is properly connected to the Delta 2, fueling of the rocket's second stage with storable Aerozine 50 and nitrogen tetroxide propellants, and multiple readiness reviews to clear the mission for takeoff.

Workers at Vandenberg lifted the Delta 2's first stage on its launch mount June 8, then added an interstage connector June 12. Ground crews mated four solid-fueled strap-on boosters in mid-June, and hoisted the Delta 2's second stage into position June 21.

ULA's Delta team powered up the Delta 2 in late June for several weeks of avionics and propulsion checkouts, then suspended the launch campaign to focus on the Delta 4-Heavy launch from Florida with NASA's Parker Solar Probe.

(https://img.novosti-kosmonavtiki.ru/144775.jpg)
A member of the Delta 2 team assists in the placement of a solid rocket booster on the first stage of the Delta 2 rocket at Vandenberg Air Force Base on June 15. Credit: USAF 30th Space Wing/Mark Mackley

The Parker Solar Probe launch was delayed several times before it lifted off early Sunday, prompting NASA and ULA to push back ICESat 2's launch by three days, giving teams time to transition from the East Coast to the West Coast.

The upcoming mission will be the 155th flight of a Delta 2 rocket since the launcher family debuted with the deployment of a GPS navigation satellite on Valentine's Day 1989.

...

Ensuring a graceful end to the Delta 2 program

...

(https://img.novosti-kosmonavtiki.ru/143822.jpg)
The penultimate Delta 2 launch last November carried NOAA's JPSS 1 weather satellite into orbit from Vandenberg Air Force Base, California. Credit: ULA/Walter Scriptunas II

...

The space agency booked the ICESat 2 launch on a Delta 2 rocket in 2013, adding a fourth flight to the Delta 2 program's final chapter. ULA has components for one additional Delta 2 launcher, but that rocket will not fly, and is likely bound for a museum display.

As with any long-lived flight program nearing retirement, NASA and ULA had to meticulously ensure they had enough spare parts to replace components that might be damaged during the final Delta 2 launch campaigns, according to Dunn.

In the final years of the program, officials kept an inventory spare parts for the launch vehicles and ground support equipment, and they faced concerns that Delta 2 personnel might want to leave the program because of its impending retirement, Dunn said.

"It's been incredibly successful for us in managing spare parts," Dunn said. "There were certain parts wh ere the vendor went out of business, or quit making the parts many years ago. So while the vendor was still in business, ULA ensured that at least one spare was made for every critical component on the rocket, and then an evaluation of the entire rocket was made.

"To pick a term out of fairy tails, the 'golden egg' process was put in place," Dunn said. "Certain components on the rocket, or its one-of-a-kind spare, were deemed 'golden eggs' and handled as such since the 2011 or 2012 timeframe. You would walk through the factory ... and you would see certain items with a big 'golden egg' placard on them."

"Here we are at the end of that process, we are still in very good shape in having at least one spare for all critical components," Dunn said.

Over the last six decades, the builders of the Delta rocket family changed names through multiple corporate mergers and acquisitions, beginning with the Douglas Aircraft Company, then succeeded by McDonnell Douglas, Boeing and United Launch Alliance, formed in 2006 by the marriage of Boeing and Lockheed Martin rocket programs.

The more powerful Delta 4 rocket built by ULA is a new design, incorporating different hydrogen-fueled engines, and wider propellant tanks than the Delta 2. Counting the Delta 4 family, the launch of ICESat 2 next month will be the 381st flight of a rocket carrying the Delta name since 1960.

NASA launch director shares his Delta 2 memories

"Delta has such a rich history, starting back in 1960," Dunn told Spaceflight Now. "If you talk to real gray-beards on the program, it was on death's door step probably at least three, maybe four times, when everyone thought for sure that was the last launch ever, and they were all out of jobs, and somehow it kept getting new life.

"For this version of Delta, we are certain that this one will not fly after ICESat 2," he said.

After stints as an Air Force as a GPS satellite analysis officer and a Titan 4 launch controller, Dunn joined the Delta 2 program at Boeing in 1996, supporting dozens of missions as a launch-day guidance engineer. One of his first missions on the Delta 2 rocket was the launch of Mars Pathfinder in December 1996, which delivered NASA's first rover to the red planet.

"One our first missions was the Mars Pathfinder mission," Dunn said. "That was the very small rover that we sent to Mars back in the fall of '96. That one was really satisfying to me because it was super-cool deep space mission with NASA, our customer at the time ... We were sending something to crawl around on the surface of Mars.

Hot Wheels produced a toy version of Mars Pathfinder's Sojourner rover before the mission's launch.

"My son was just a couple of years old, so it something I could relate to him with toys," Dunn said. "So Pathfinder sticks out."

(https://img.novosti-kosmonavtiki.ru/144657.jpg)
NASA launch director Tim Dunn (lower right) oversees the countdown before the final Delta 2 launch from Cape Canaveral in September 2011. Credit: NASA/Kim Shiflett

Dunn joined NASA's Launch Services Program in 2000 as a Delta 2 avionics and flight controls engineer, then became NASA's Delta 2 vehicle systems engineer in 2003, leading the agency's technical team ensuring Delta 2 rockets were ready to loft science probes into the solar system.

"From a constellation build-up point of view, the Globalstar sequence of launches that we did back in the summer of '99 timeframe," Dunn said. "Those were really fun because of the repetition. I want to say we were launching every couple of weeks there, at least for a few of them, fire to fire.

"Supporting the Air Force through all those years, that's a special memory with GPS," Dunn said. "From 1989 when GPS 2-1 first launched, as you progressed through the '90s, that was the time when GPS went from this military system that only the military used, to essentially a common everyday person's utility. That was really fun to be supporting and sustaining the constellation that everyone was beginning to use. Fast forward to 2018, and (when) you talk to younger kids today about GPS, they can't imagine life without GPS, on your phone, on your watch, in your car."

Other Delta 2 launches high on Dunn's favorites list include the back-to-back liftoffs in June and July 2003 with NASA's Spirit and Opportunity Mars rovers. Opportunity, which took off second in 2003's interplanetary launch window, had to use a version of the rocket known as the Delta 2-Heavy, the first Delta 2 to fly with uprated, more powerful solid rocket boosters.

"We launched them both in the summer, so we were able to hit the Mars window with two different launches from Complex 17 (at Cape Canaveral)," Dunn said. "One was a standard Delta 2-7900 series, and the other with the Heavy. That was a huge development effort, bringing the Heavy online, a real challenge because of the planetary window we had to hit."

Dunn's first mission as launch director was the last Delta 2 flight from Cape Canaveral in 2011.

"That one was very special," he told Spaceflight Now in an interview.

Dunn said his move from the Air Force's Titan 4 program, which primarily launched one-of-a-kind, costly U.S. military satellites, to the workhorse Delta 2 was a major change. The Titan 4 team vastly outnumbered the Delta 2 workforce, despite the Delta 2's higher launch rate.

"I really enjoyed those Titan 4 launches, but it was hard to identify with the whole team, and the rocket was kind of a fairly complex rocket, especially with the Centaur second stage, just big and fun," Dunn said. "Then I went to the Delta 2, and it was a little smaller. You could get your hands around the systems, and you could walk the tower a lot more easily, and the team that you were working with was kind of an order of magnitude smaller, so that made it feel more like family.

"That's one of the things that I'll miss," Dunn said. "That may be replicated on some of the newer providers, especially the smaller providers that have smaller teams ... Just my knowledge of the hardware systems on Delta 2, when you grow up and you invest so many years in a particular rocket, you really feel like you know it inside and out."

The Delta 2's iconic color will also become a part of space history with the rocket's retirement.

"And of course that baby blue paint scheme," Dunn said. "I'm going to miss that because I don't see another rocket out there painted in baby blue just yet, but maybe there will be one coming."

[свернуть]

ЦитироватьDELTA II TO LAUNCH ICESAT-2

• Rocket: Delta II
• Mission: ICESat-2
• Launch Date: Saturday, Sept. 15, 2018
• Launch Time: To be announced
• Launch Broadcast: To be announced
• Launch Location: Space Launch Complex-2, Vandenberg Air Force Base, California

(https://img.novosti-kosmonavtiki.ru/220057.jpg)

Mission Information: United Launch Alliance will use the final Delta II rocket to launch the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) for NASA to measure the thickness of Earth's polar ice sheets. The satellite's primary instrument will pulse its laser at Earth 10,000 times a second and precisely measure the time it takes the beams to bounce off the ground and return to ICESat-2 to deduce the elevation below within the accuracy of 4 millimeters.

The satellite advances the capabilities of its predecessor, ICESat-1, launched by a Delta II rocket and operated from 2003 to 2009.

Launch Notes: This will be the final flight of the venerable Delta II rocket, which has been in use since 1989.

Launch Updates: To keep up to speed with updates to the launch countdown, dial the ULA launch hotline at 1-877-852-4321 or join the conversation at www.facebook.com/ulalaunch, (https://www.facebook.com/ulalaunch) twitter.com/ulalaunch  (https://twitter.com/ulalaunch)and instagram.com/ulalaunch (https://instagram.com/ulalaunch); hashtags #deltaii #icesat2
 
Go Delta! Go ICESat-2!

ЦитироватьAug. 17, 2018
MEDIA ADVISORY M18-122

NASA to Host Media Briefing on New Ice-Monitoring Mission

(https://img.novosti-kosmonavtiki.ru/207769.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat2_astrotech.jpg)
NASA's ICESat-2 spacecraft undergoing final testing at Vandenberg Air Force Base in California in preparation for launch on Sept. 15.
Credits: USAF 30th Space Wing/Timonthy Trenkle

NASA will host a media teleconference at 1 p.m. EDT Wednesday, Aug. 22, to discuss the upcoming launch of the Ice, Cloud and land Elevation Satellite (ICESat-2), which will fly NASA's most advanced laser altimeter to measure Earth's changing ice. The teleconference will stream live on NASA's website (https://www.nasa.gov/live).

ICESat-2 is scheduled to launch Sept. 15 on a mission to provide critical, precision measurements of Earth's ice sheets, glaciers and sea ice, which will help scientists better understand how changes at the poles will affect people around the world.

The briefing participants are:

[/li]
• Tom Wagner, cryosphere program scientist in the Science Mission Directorate (SMD) at NASA Headquarters
• Richard Slonaker, ICESat-2 program executive in SMD
• Doug McLennan, ICESat-2 project manager at NASA's Goddard Space Flight Center
• Donya Douglas-Bradshaw, Advanced Topographic Laser Altimeter System (ATLAS) instrument manager at Goddard
• Tom Neumann, ICESat-2 deputy project scientist at Goddard
  

At the time of the briefing, associated graphics will be available online at: 

http://svs.gsfc.nasa.gov/13044

...
The teleconference will be followed at 2:30 p.m. by a live, televised discussion with social media followers and mission experts at Goddard, which manages the ICESat-2 mission for SMD. It will be carried on NASA Television, the agency's website (https://www.nasa.gov/live) and NASA's Facebook (https://www.facebook.com/ICEatNASA/videos/1904810493146066/?__xts__%5b0%5d=68.ARBPVBnQOOEUYfzhsPr6yrTjuk23g3CZljOUPM7GqI1eWlz7YzxOJehS44dhbtS1Sh92ihF_TM2O8qGYQUpiBBJPMLxPKq92LTclb1afOl74G7AWVT_iqaX8nZd9EeP4NwKsv6vBAic2&__tn__=-R) Live, Periscope (https://periscope.tv/nasa), Twitter (http://twitter.com/nasa), Twitch (https://www.twitch.tv/nasa/), YouTube (http://www.youtube.com/NASA), and UStream (http://www.ustream.tv/nasahdtv) channels. Members of the public can ask questions with the hashtag #askNASA on Twitter or in the comment section of the NASA Ice Facebook page (https://www.facebook.com/ICEatNASA).

ICESat-2 will launch from Vandenberg Air Force Base in California aboard United Launch Alliance's final Delta II rocket. For more information on the mission, visit:

https://nasa.gov/icesat-2

Last Updated: Aug. 17, 2018
Editor: Sean Potter

ЦитироватьICESat-2 L-30 Science Briefing Graphics
Released on August 22, 2018

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/icesat2_orbit_short_720p30.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/icesat2_orbit_short_720p30.mp4) (1:24)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/icesat2_orbit_short_720p30.mp4)
ICESat-2 will complete all 1,387 of its orbits every 91 days.

Спойлер

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/ICESat2__deploy_beauty_ipod_lg.m4v (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/ICESat2__deploy_beauty_ipod_lg.m4v) (0:53)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/ICESat2__deploy_beauty_ipod_lg.m4v)
Animation showing deployment of the ICESat-2 spacecraft and the laser turning on.

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Build.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Build.mp4) (0:47)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Build.mp4)
Footage of the Advanced Topographic Laser Altimeter System (ATLAS) under construction at NASA's Goddard Space Flight Center.

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/TVAC.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/TVAC.mp4) (0:28 )
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/TVAC.mp4)
Footage of the ATLAS instrument entering the Thermal Vacuum Chamber at NASA Goddard.

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Laser.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Laser.mp4) (0:26)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Laser.mp4)
Animation showing the ATLAS laser firing and how its six beams will cover ground tracks across Earth's surface.

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/SEA_ICE_V06_1.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/SEA_ICE_V06_1.mp4) (0:49)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/SEA_ICE_V06_1.mp4)
Animation showing how ICESat-2 will measure the height of sea ice freeboard (hf) – the portion of sea ice floating above the water – to estimate sea ice thickness (hi).

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Rink.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Rink.mp4) (1:03)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Rink.mp4)
This data visualization shows swaths of ice elevation data gathered over the Rink Glacier in Greenland by NASA's Airborne Topographic Mapper, an airborne lidar flown over Greenland regularly since 1993 and on NASA's Operation IceBridge since 2009. The end of the animation compares the scale of the airborne data to the global coverage ICESat-2 will provide.

https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Tom_orbit.mp4 (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Tom_orbit.mp4) (0:37)
Download (https://svs.gsfc.nasa.gov/vis/a010000/a013000/a013044/Tom_orbit.mp4)
Animation showing how ICESat-2's orbit tracks converge at latitudes of 88 N and 88 S around the North and South poles, providing dense data coverage at those locations.

[свернуть]

ЦитироватьICESat-2 Adds the Third Dimension to Earth
Доступ по ссылке

NASA Goddard (https://www.youtube.com/channel/UCAY-SMFNfynqz1bdoaV8BeQ)

Дата загрузки: 21 авг. 2018 г.

ICESat-2 will provide scientists with height measurements that create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, forests and more. The single instrument on ICESat-2 is ATLAS, the Advanced Topographic Laser Altimeter System, will measure melting ice sheets and investigate how this effects sea level rise, investigate changes in the mass of ice sheets and glaciers, estimate and study sea ice thickness, and measure the height of vegetation in forests and other ecosystems worldwide. "Eternal Circle," Laurent Dury, Koka Media SACEM Complete transcript available.

ЦитироватьAug. 22, 2018
RELEASE 18-074

NASA Launching Advanced Laser to Measure Earth's Changing Ice

(https://img.novosti-kosmonavtiki.ru/207773.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesatphoto.jpg)
NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) spacecraft arrives at the Astrotech Space Operations facility at Vandenberg Air Force Base in California ahead of its scheduled launch on Sept. 15, 2018.
Credits: U.S. Air Force/Vanessa Valentine

Next month, NASA will launch into space the most advanced laser instrument of its kind, beginning a mission to measure – in unprecedented detail – changes in the heights of Earth's polar ice.

NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, capturing 60,000 measurements every second.

"The new observational technologies of ICESat-2 – a top recommendation of the scientific community in NASA's first Earth science decadal survey – will advance our knowledge of how the ice sheets of Greenland and Antarctica contribute to sea level rise," said Michael Freilich, director of the Earth Science Division in NASA's Science Mission Directorate.

ICESat-2 will extend and improve upon NASA's 15-year record of monitoring the change in polar ice heights, which started in 2003 with the first ICESat mission and continued in 2009 with NASA's Operation IceBridge, an airborne research campaign that kept track of the accelerating rate of change.

Спойлер

(https://img.novosti-kosmonavtiki.ru/208374.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat-2-infographic.jpg)
NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will measure height with a laser instrument that features components designed to provide precise data.
Credits: NASA/Adriana Manrique Gutierrez

A Technological Leap

ICESat-2 represents a major technological leap in our ability to measure changes in ice height. Its Advanced Topographic Laser Altimeter System (ATLAS) measures height by timing how long it takes individual light photons to travel from the spacecraft to Earth and back.

"ATLAS required us to develop new technologies to get the measurements needed by scientists to advance the research," said Doug McLennan, ICESat-2 project manager at NASA's Goddard Space Flight Center. "That meant we had to engineer a satellite instrument that not only will collect incredibly precise data, but also will collect more than 250 times as many height measurements as its predecessor."

ATLAS will fire 10,000 times each second, sending hundreds of trillions of photons to the ground in six beams of green light. The roundtrip of individual laser photons from ICESat-2 to Earth's surface and back is timed to the billionth of a second to precisely measure elevation.

With so many photons returning from multiple beams, ICESat-2 will get a much more detailed view of the ice surface than its predecessor, ICESat. In fact, if the two satellites were flown over a football field, ICESat would take only two measurements – one in each end zone – whereas ICESat-2 would collect 130 measurements between each end zone.

As it circles Earth from pole to pole, ICESat-2 will measure ice heights along the same path in the polar regions four times a year, providing seasonal and annual monitoring of ice elevation changes.

https://www.youtube.com/watch?v=rOXjuiQ3R_o (https://www.youtube.com/watch?v=rOXjuiQ3R_o)
NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will provide scientists with height measurements that create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, and forests.
Credits: NASA/Ryan Fitzgibbons
Watch this video on YouTube. (https://www.youtube.com/watch?v=rOXjuiQ3R_o)

Tracking Ice Melt

Hundreds of billions of tons of land ice melt or flow into the oceans annually, contributing to sea level rise worldwide. In recent years, contributions of melt from the ice sheets of Greenland and Antarctica alone have raised global sea level by more than a millimeter a year, accounting for approximately one-third of observed sea level rise, and the rate is increasing.

ICESat-2 data documenting the ongoing height change of ice sheets will help researchers narrow the range of uncertainty in forecasts of future sea level rise and connect those changes to climate drivers.

ICESat-2 also will make the most precise polar-wide measurements to date of sea ice freeboard, which is the height of sea ice above the adjacent sea surface. This measurement is used to determine the thickness and volume of sea ice. Satellites routinely measure the area covered by sea ice and have observed an Arctic sea ice area decline of about 40 percent since 1980, but precise, region-wide sea ice thickness measurements will improve our understanding of the drivers of sea ice retreat and loss.

Although floating sea ice doesn't change sea level when it melts, its loss has different consequences. The bright Arctic ice cap reflects the Sun's heat back into space. When that ice melts away, the dark water below absorbs that heat. This alters wind and ocean circulation patterns, potentially affecting Earth's global weather and climate.

Beyond the poles, ICESat-2 will measure the height of ocean and land surfaces, including forests. ATLAS is designed to measure both the tops of trees and the ground below, which – combined with existing datasets on forest extent – will help researchers estimate the amount of carbon stored in the world's forests. Researchers also will investigate the height data collected on ocean waves, reservoir levels, and urban areas.

Potential data users have been working with ICESat-2 scientists to connect the mission science to societal needs. For example, ICESat-2 measurements of snow and river heights could help local governments plan for floods and droughts. Forest height maps, showing tree density and structure, could improve computer models that firefighters use to forecast wildfire behavior. Sea ice thickness measurements could be integrated into forecasts the U.S. Navy issues for navigation and sea ice conditions.

"Because ICESat-2 will provide measurements of unprecedented precision with global coverage, it will yield not only new insight into the polar regions, but also unanticipated findings across the globe," said Thorsten Markus, an ICESat-2 project scientist at Goddard. "The capacity and opportunity for true exploration is immense."

[свернуть]

​ICESat-2 is scheduled to launch Sept. 15 from Vandenberg Air Force Base in California.

Last Updated: Aug. 22, 2018
Editor: Karen Northon

Цитироватьhttps://scontent-arn2-1.xx.fbcdn.net/v/t42.9040-29/10000000_1972880349485482_3132814768507715584_n.mp4?_nc_cat=0&efg=eyJ2ZW5jb2RlX3RhZyI6InNkIn0%3D&oh=e9809a86530408171eaa57343da6d778&oe=5B7DE2F8 (https://scontent-arn2-1.xx.fbcdn.net/v/t42.9040-29/10000000_1972880349485482_3132814768507715584_n.mp4?_nc_cat=0&efg=eyJ2ZW5jb2RlX3RhZyI6InNkIn0%3D&oh=e9809a86530408171eaa57343da6d778&oe=5B7DE2F8) (28:44)

ЦитироватьInstallation of ice-measuring satellite caps assembly of last Delta 2 rocket
August 28, 2018 (https://spaceflightnow.com/2018/08/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

(https://img.novosti-kosmonavtiki.ru/144735.jpg)
Technicians open and inspect the flight door to ICESat 2's laser instrument shortly after the spacecraft arrived at Vandenberg Air Force Base, California, in June. Credit: USAF 30th Space Wing/Timothy Trenkle

NASA's ICESat 2 satellite has been bolted atop a United Launch Alliance Delta 2 rocket at Vandenberg Air Force Base in California as ground teams prepare for the workhorse launcher's final liftoff Sept. 15.

Equipped with a six-beam laser altimeter, the spacecraft will monitor changes in Earth's land and sea ice, continuing a series of measurements which have shown ice is melting around the edges of Greenland and Antarctica, and is thinning in the oceans.

ICESat 2 — short for Ice, Cloud and land Elevation Satellite 2 — was raised atop the Delta 2 rocket early Sunday at Vandenberg after a short road trip inside a shipping container fr om a nearby Astrotech satellite processing facility. A crane hoisted the spacecraft — about the size of a small camper trailer — into the mobile gantry at Vandenberg's Space Launch Complex 2-West, the Delta 2's West Coast launch pad.

Ground crews lowered the spacecraft atop the Delta 2's second stage, then began preparations to install the rocket's clamshell-like payload fairing around the satellite, the final step in assembly of the 128-foot-tall (39-meter) launch vehicle.

The spacecraft's transfer to the launch pad occurred two days later than planned to resolve an issue with a piece of ground support equipment, but the the schedule hiccup is not expected to delay the launch.

Liftoff is scheduled for Sept. 15 at 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT) on the 155th and final flight of ULA's venerable Delta 2 rocket.

Heading south from Vandenberg, the Delta 2 will shed its four solid rocket boosters and kerosene-fueled first stage. Two firings of the Delta 2's second stage engine will maneuver the ICESat 2 satellite into an orbit around 300 miles (500 kilometers).

Separation of ICESat 2 from the Delta 2 rocket is expected nearly 53 minutes after liftoff, followed by a third burn of the Delta 2 upper stage engine to set up for deployment of four tiny CubeSats developed by students at UCLA, Cal Poly and the University of Central Florida.

A fourth burn by the Delta 2's second stage engine will de-orbit the rocket for a fiery, destructive re-entry to avoid creating space junk.

The launch next month will mark the retirement of the Delta 2 rocket after a storied record of missions since its debut in 1989. Delta 2 rockets have launched NASA probes to the moon, Mars, Mercury, comets and asteroids, plus all of the U.S. Air Force's Global Positioning System navigation satellites in the 1990s and 2000s.

Спойлер

(https://img.novosti-kosmonavtiki.ru/144792.jpg)
The Delta 2 rocket set to launch NASA's ICESat 2 satellite is pictured on its launch pad in June. Credit: NASA/Randy Beaudoin

The ICESat 2 satellite was built by Northrop Grumman Innovation Systems, and its single instrument — the Advanced Topographic Laser Altimeter System, or ATLAS — was developed at NASA's Goddard Space Flight Center.

The ATLAS laser will split into six beams once it leaves the instrument. ICESat 2 will measure the time it takes for the laser beams to bounce off of Earth's surface and return to the satellite, giving scientists information about the height of ice sheets and forest canopies.

"ATLAS essentially acts like a stop watch," said Donya Douglas-Bradshaw, ATLAS instrument manager at Goddard. "The ATLAS laser fires 10,000 pulses per second with a trillion photons in each shot. Each time the laser fires, it starts the stop watch. It takes about 3.3 milliseconds for the beam to exit the instrument, reach the surface and return back to the telescope."

The laser package "has the ability to time tag a single photon to billionth of a second accuracy," Douglas-Bradshaw said in a briefing with reporters last week. "This precision allows the instrument to detect annual changes in ice elevation on the order of half of a centimeter (0.2 inches)."

The ICESat 2 satellite weighs around 3,340 pounds (1,515 kilograms) at launch, according to Doug McLennan, ICESat 2's project manager at Goddard.

McLennan said the spacecraft has enough fuel to operate more than 10 years. ICESat 2's primary mission is scheduled for three years, but could be extended.

ICESat 2 is a more advanced replacement for NASA's ICESat satellite, which measured ice coverage and thickness from 2003 through 2009. ICESat carried a laser producing a single beam, while ICESat 2's upgraded laser instrument will generate six beams to better see wh ere ice is melting and flowing, helping quantify and identify the impacts of warming global temperatures.

The ICESat 2 mission is expected to cost NASA more than $1.05 billion, including expenditures during design, development, launch and operations of the satellite.

NASA mounted airborne ice research campaigns since ICESat's laser instrument failed in 2009, continuing observations of certain ice flows to bridge the gap between ICESat and the launch of ICESat 2. But global coverage will only resume with the launch and commissioning of the new satellite.

"Since the end of the first ICESat mission, NASA has not had the ability to measure ice sheet surface elevation and sea ice thickness on a global scale," Richard Slonaker, ICESat 2 program executive at NASA Headquarters. "That all changes with the launch of ICESat 2."

"What we are hopeful for is that we are going to be able to tie changes in the land ice and sea ice to other specific changes in the Earth system," said Tom Wagner, cryosphere program scientist at NASA Headquarters.

"Ultimately, what we're trying to understand are the processes and the climate drivers that are guiding this change," Wagner said.

[свернуть]

ЦитироватьAug. 28, 2018

Counting on NASA's ICESat-2

NASA is about to launch the agency's most advanced laser instrument of its kind into space. The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, will provide critical observations of how ice sheets, glaciers and sea ice are changing, leading to insights into how those changes impact people where they live.

Launch is scheduled for Sept. 15, and as we count down the days, we're counting up 10 things you should know about ICESat-2:

Спойлер

(https://img.novosti-kosmonavtiki.ru/207537.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/28785111927_a5343ae894_k.jpg)
The ICESat-2 satellite undergoes tests one last time before it is placed in the rocket. ICESat-2, scheduled to launch Sept. 15, will precisely measure the height of Earth's ice and monitor change.
Credits: USAF 30th Space Wing/Timothy Trenkle

1 Space Laser

There's only one scientific instrument on ICESat-2, but it is a marvel. The Advanced Topographic Laser Altimeter System, or ATLAS, measures height by precisely timing how long it takes individual photons of light fr om a laser to leave the satellite, bounce off Earth, and return to the satellite. Hundreds of people at NASA's Goddard Space Flight Center in Greenbelt, Maryland, worked to build this smart-car-sized instrument to exacting requirements so that scientists can measure minute changes in our planet's ice.

2 Types of Ice

Not all ice is the same. Land ice, like the ice sheets in Greenland and Antarctica, or glaciers dotting the Himalaya, builds up as snow falls over centuries and forms compacted layers. When it melts, it can flow into the ocean and raise sea level. Sea ice, on the other hand, forms when ocean water freezes. It can last for years, or a single winter. When sea ice disappears, there is no effect on sea level (think of a melting ice cube in your drink), but it can change climate and weather patterns far beyond the poles.

3-Dimensional Earth

ICESat-2 will measure elevation to see how much glaciers, sea ice and ice sheets are rising or falling. NASA's fleet of satellites collect detailed images of our planet that show the changing extent of features like ice sheets and forests, and with ICESat-2's data, scientists can add the third dimension – height – to those portraits of Earth.

4 Seasons, 4 Measurements

ICESat-2's orbit will make 1,387 unique ground tracks around Earth in 91 days – and then start the same ground pattern again at the beginning. This allows the mission to measure the same ground tracks four times a year and scientists to see how glaciers and other frozen features change with the seasons – including over winter.

532 Nanometer Wavelength

https://www.youtube.com/watch?v=agmmr5XvgMM (https://www.youtube.com/watch?v=agmmr5XvgMM)
(video (https://www.youtube.com/watch?v=agmmr5XvgMM) 0:35)
The lasers on ATLAS, ICESat-2's instrument, shine at a wavelength of 532 nanometers – a bright green on the visible spectrum.
Credits: NASA's Goddard Space Flight Center/Ryan Fitzgibbons
Download this video in HD formats from NASA Goddard's Scientific Visualization Studio (https://svs.gsfc.nasa.gov/12768)

The ATLAS instrument will measure ice with a laser that shines at 532 nanometers – a bright green on the visible spectrum. When these laser photons return to the satellite, they pass through a series of filters that block any light that's not exactly at this wavelength. This helps the instrument from being swamped with all the other shades of sunlight naturally reflected from Earth.

6 Laser Beams

While the first ICESat satellite (2003-2009) measured ice with a single laser beam, ICESat-2 splits its laser light into six beams – the better to cover more ground (or ice). The arrangement of the beams into three pairs will also allow scientists to assess the slope of the surface they're measuring.

7 Kilometers per Second

ICESat-2 will zoom above the planet at 7 km per second (4.3 miles per second), completing an orbit around Earth in 90 minutes. The orbits have been set to converge at the 88-degree latitude lines around the poles, to focus the data coverage in the region wh ere scientists expect to see the most change.

800-Picosecond Precision

All of those height measurements result from timing the individual laser photons on their 600-mile roundtrip between the satellite and Earth's surface – a journey that is timed to within 800 picoseconds. That's a precision of less than a billionth of a second. NASA engineers had to custom build a stopwatch-like device, since no existing timers fit the strict requirements.

9 Years of Operation IceBridge

(https://img.novosti-kosmonavtiki.ru/207768.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icebridgeak18.jpg)
Icy Bay, in the Wrangell-Saint Elias Wilderness, as seen from an Operation IceBridge flight in August 2018. Operation IceBridge flights have measured changing ice in the Arctic and Antarctic since 2009.
Credits: NASA

As ICESat-2 measures the poles, it adds to NASA's record of ice heights that started with the first ICESat and continued with Operation IceBridge, an airborne mission that has been flying over the Arctic and Antarctic for nine years. The campaign, which bridges the gap between the two satellite missions, has flown since 2009, taking height measurements and documenting the changing ice.

10,000 pulses a second

ICESat-2's laser will fire 10,000 times in one second. The original ICESat fired 40 times a second. More pulses mean more height data. If ICESat-2 flew over a football field, it would take 130 measurements between end zones; its predecessor, on the other hand, would have taken one measurement in each end zone.

ICESat-2's fast-firing laser, combined with the instrument's timing precision, sensitive photon-detection technology and other features will allow the ICESat-2 mission to measure the average annual change in vast ice sheets down to the width of a pencil.

By: Kate Ramsayer (mailto:kate.d.ramsayer@nasa.gov?subject=Re)
NASA's Goddard Space Flight Center (http://www.nasa.gov/goddard), Greenbelt, Md.

[свернуть]

Last Updated: Aug. 28, 2018
Editor: Sara Blumberg

Цитировать(https://img.novosti-kosmonavtiki.ru/185409.jpg)The GLOBE Program‏Подлинная учетная запись @GLOBEProgram (https://twitter.com/GLOBEProgram) 2 ч. назад (https://twitter.com/GLOBEProgram/status/1037401476887244800)

Get ready to #DoScience (https://twitter.com/hashtag/DoScience?src=hash)! The "Trees Around the GLOBE" student research campaign will launch with NASA #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) satellite on 15 September. This campaign will create a community to compare your observations to @NASA_ICE (https://twitter.com/NASA_ICE) #SatelliteData (https://twitter.com/hashtag/SatelliteData?src=hash)

(https://img.novosti-kosmonavtiki.ru/169272.png)

ЦитироватьSept. 4, 2018
MEDIA ADVISORY M18-015

ICESat-2 Launch Briefings and Events from California

(https://img.novosti-kosmonavtiki.ru/207771.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat-2_image_above_earth.jpg)
An artist illustration of NASA's ICESat-2 satellite above Earth. Image credit: NASA/Goddard Space Flight Center

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2 (https://www.nasa.gov/content/goddard/icesat-2), a mission to measure the changing height of Earth's ice, is scheduled to launch Saturday, Sept. 15, with a 40-minute window opening at 8:46 a.m. EDT (5:46 a.m. PDT). The spacecraft will lift off from Space Launch Complex 2 (SLC-2) at Vandenberg Air Force Base in California on the final launch of a United Launch Alliance Delta II rocket. The deadline for media to apply for accreditation for this launch has passed.

Launch coverage will begin on NASA Television and the agency's website (http://www.nasa.gov/live) at 8:10 a.m. EDT (5:10 a.m. PDT).

ICESat-2 will measure the height of our changing Earth, one laser pulse at a time, 10,000 laser pulses per second. The satellite will carry a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), which measures the travel times of laser pulses to calculate the distance between the spacecraft and Earth's surface. ICESat-2 will provide scientists with height measurements that create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain, including glaciers, sea ice and forests.

NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages development of the ICESat-2 mission, including mission systems engineering and mission operations on behalf of the agency's Science Mission directorate. Goddard also built and tested the ATLAS instrument. The ICESat-2 spacecraft was built and tested by Northrop Grumman (http://www.northropgrumman.com/Pages/default.aspx) in Gilbert, Arizona. United Launch Alliance (https://www.ulalaunch.com/) of Centennial, Colorado, is providing the Delta II launch service. NASA's Launch Services Program (https://www.nasa.gov/centers/kennedy/launchingrockets/index.html), based at Kennedy Space Center in Florida, is responsible for launch service acquisition, integration, analysis and launch management.

The following is a complete schedule of mission coverage, including opportunities for media participation at Vandenberg.

L-2 Day (Thursday, Sept. 13)

Prelaunch Mission Briefing

A prelaunch mission briefing will be held at 4 p.m. EDT (1 p.m. PDT) at NASA Building 836 and will be broadcast live on NASA Television and the agency's website (http://www.nasa.gov/live).

Participants:

[/li]
• Tom Wagner, ICESat-2 program scientist, NASA Headquarters
• Doug McLennan, ICESat-2 project manager, NASA Goddard Space Flight Center
• Donya Douglas-Bradshaw, ATLAS instrument project manager, NASA Goddard Space Flight Center
• Tom Neumann, ICESat-2 deputy project scientist, NASA Goddard Space Flight Center
• Lori Magruder, University of Texas at Austin, ICESat-2 science definition team lead
• Helen Fricker, Scripps Institution of Oceanography, La Jolla, Calif., ICESat-2 science definition team member
• Bill Barnhart, ICESat-2 program manager, Northrop Grumman
• Tim Dunn, launch director, NASA Kennedy Space Center
• Scott Messer, program manager, NASA Programs, United Launch Alliance
• 1st Lt. Daniel Smith, launch weather officer, 30th Space Wing, Vandenberg Air Force Base
  

...

L-0 Launch Day (Saturday, Sept. 15)

NASA TV Launch Coverage

NASA TV live launch coverage will begin at 8:10 a.m. EDT (5:10 a.m. PDT). For NASA TV downlink information, schedules and links to streaming video, visit http://www.nasa.gov/ntv.
...

NASA Web Prelaunch and Launch Coverage

Prelaunch and launch day coverage of ICESat-2 will be available on the NASA website (https://www.nasa.gov/content/goddard/icesat-2). Coverage will include live streaming and blog updates beginning at 8:10 a.m. EDT (5:10 a.m. PDT) as the countdown milestones occur. ... You can follow countdown coverage on our launch blog at https://blogs.nasa.gov/icesat2/.

Last Updated: Sept. 4, 2018
Editor: Linda Herridge

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 7 сент. (https://twitter.com/ulalaunch/status/1038159658563919874)

Heads up! @NASA_LSP (https://twitter.com/NASA_LSP) @NASA_ICE (https://twitter.com/NASA_ICE) and @ulalaunch (https://twitter.com/ulalaunch) are holding a tweet chat about the #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) mission. Join us Sept. 10 at 3:30pmET/12:30pmPT. Have a question? Use #AskNASA (https://twitter.com/hashtag/AskNASA?src=hash) to get it into the mix.

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ЦитироватьNASA missions study Earth's frozen water: GRACE-FO & ICESat-2

SciNews (https://www.youtube.com/channel/UCjU6ZwoTQtKWfz1urL7XcbA)

Опубликовано: 8 сент. 2018 г.

GRACE-FO and ICESat-2 are the latest NASA missions that help scientists study the cryosphere, Earth's frozen water. The GRACE-FO mission was launched on 22 May 2018 aboard a SpaceX Falcon 9 rocket, while ICESat-2 is scheduled to launch on 15 September 2018.

ЦитироватьDELTA II TO LAUNCH ICESAT-2

(https://img.novosti-kosmonavtiki.ru/220057.jpg)

• Rocket: Delta II
• Mission: ICESat-2
• Launch Date: Saturday, Sept. 15, 2018
• Launch Time: Launch is planned for 5:46 a.m. PDT
• Launch Broadcast: Tune in live beginning at 5:10 a.m. PDT
• Launch Location: Space Launch Complex-2, Vandenberg Air Force Base, California 

Mission Information: United Launch Alliance will use the final Delta II rocket to launch the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) for NASA to measure the thickness of Earth's polar ice sheets. The satellite's primary instrument will pulse its laser at Earth 10,000 times a second and precisely measure the time it takes the beams to bounce off the ground and return to ICESat-2 to deduce the elevation below within the accuracy of 4 millimeters.

The satellite advances the capabilities of its predecessor, ICESat-1, launched by a Delta II rocket and operated from 2003 to 2009.

Launch Notes: This will be the final flight of the venerable Delta II rocket, which has been in use since 1989.

Launch Updates: To keep up to speed with updates to the launch countdown, dial the ULA launch hotline at 1-877-852-4321 or join the conversation at www.facebook.com/ulalaunch, (https://www.facebook.com/ulalaunch) twitter.com/ulalaunch  (https://twitter.com/ulalaunch)and instagram.com/ulalaunch (https://instagram.com/ulalaunch); hashtags #deltaii #icesat2
 
Go Delta! Go ICESat-2!

Цитировать(https://img.novosti-kosmonavtiki.ru/185703.jpg)Northrop Grumman‏Подлинная учетная запись @northropgrumman (https://twitter.com/northropgrumman) 4 ч. назад (https://twitter.com/northropgrumman/status/1039185505143988224)

We are just 5 days away from the launch of the #NorthropGrumman (https://twitter.com/hashtag/NorthropGrumman?src=hash)-built #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) spacecraft, scheduled to launch aboard a @ulalaunch (https://twitter.com/ulalaunch) #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) on September 15 from @30thSpaceWing (https://twitter.com/30thSpaceWing). Stay tuned here for more info and live launch coverage!
@NASA_ICE (https://twitter.com/NASA_ICE)

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Цитировать(https://img.novosti-kosmonavtiki.ru/185703.jpg)Northrop Grumman‏Подлинная учетная запись @northropgrumman (https://twitter.com/northropgrumman) 4 ч. назад (https://twitter.com/northropgrumman/status/1039186743243755521)

In addition to designing and building the #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) spacecraft, we are also providing 4 Graphite Epoxy Motors (GEM 40) that will give the @ulalaunch (https://twitter.com/ulalaunch) #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) the initial thrust needed to escape Earth's gravity! Learn more: http://ms.spr.ly/6018rAk0r  (https://t.co/0xKMTKctEa)
#NorthropGrumman (https://twitter.com/hashtag/NorthropGrumman?src=hash)

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ЦитироватьLaunch Week Arrives for ICESat-2

Anna Heiney (https://blogs.nasa.gov/icesat2/author/aheiney/)
Posted Sep 11, 2018 at 3:47 pm

(https://img.novosti-kosmonavtiki.ru/130826.jpg) (https://img.novosti-kosmonavtiki.ru/130826.jpg)
The ICESat-2 mission will measure the changing height of Earth's glaciers, ice sheets and sea ice, one laser pulse at a time, 10,000 laser pulses per second. Image credit: NASA

NASA and United Launch Alliance launch and mission partners are gathered at Vandenberg Air Force Base in California for the final week of final prelaunch activities for the agency's Ice, Cloud and land Elevation Satellite-2, or ICESat-2. The three-year mission is scheduled to launch at 8:46 a.m. EDT (5:46 a.m. PDT) on Saturday, Sept. 15, with liftoff aboard a ULA Delta II rocket fr om Space Launch Complex-2 (SLC-2).

Launch of the ICESat-2 spacecraft also will mark the final flight of the Delta II, which has served as a workhorse for NASA, the U.S. military and other customers since its 1989 debut.

Several significant prelaunch milestones are complete. The ICESat-2 spacecraft has been transported from the Astrotech payload processing facility to SLC-2, wh ere it has since been lifted, mated atop the rocket, and encapsulated inside the payload fairing that will protect it during the first minutes of flight.

Tune in Thursday for the prelaunch briefing at 4 p.m. EDT (1 p.m. PDT) on NASA TV (https://www.nasa.gov/live), and be sure to join us here on NASA's Launch Blog or on NASA TV for countdown coverage beginning Saturday at 8:10 a.m. EDT (5:10 a.m. PDT).

ЦитироватьCountdown to ICESat-2 Launch

NASA Goddard (https://www.youtube.com/channel/UCAY-SMFNfynqz1bdoaV8BeQ)

Опубликовано: 12 сент. 2018 г.

NASA is about to launch the agency's most advanced laser instrument of its kind into space. The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, will provide critical observations of how ice sheets, glaciers and sea ice are changing, leading to insights into how those changes impact people where they live.

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 19 ч. назад (https://twitter.com/ulalaunch/status/1039682043351916544)

ULA's #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) rocket will launch NASA's #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) mission from Vandenberg Air Force Base, California, on Saturday, Sept. 15, at 5:46 a.m. PDT. In the area? Check out the launch visibility. Not in the area? The live broadcast begins at 5:10 a.m. PDT.
http://bit.ly/dii_icesat2  (https://t.co/h5G3VkAmnV)

(https://img.novosti-kosmonavtiki.ru/168987.jpg)

ЦитироватьNAVAREA XII 380/2018 (83)

EASTERN NORTH PACIFIC.
1. HAZARDOUS OPERATIONS 151212Z TO 151547Z SEP,
   ALTERNATE 1212Z TO 1547Z DAILY 16 THRU 18 SEP
   IN AREA BOUND BY
   11-15N 123-14W, 11-22N 124-23W,
   16-18N 123-52W, 16-11N 122-42W.
2. CANCEL THIS MSG 181647Z SEP 18.

( 100729Z SEP 2018 )


HYDROPAC 3304/2018 (83)

SOUTH PACIFIC.
DNC 06.
1. SATELLITE RE-ENTRY 151443Z TO 151742Z SEP,
   ALTERNATE 1443Z TO 1742Z DAILY 16 THRU 18 SEP
   IN AREA BOUND BY
   43-30S 153-12W, 43-30S 152-42W,
   57-30S 155-30W, 57-30S 156-00W.
2. CANCEL THIS MSG 181842Z SEP 18.

( 100739Z SEP 2018 )

ЦитироватьUnited Launch Alliance to Launch Final Delta II with NASA's ICESat-2

Delta II ICESat-2 Launch Information Page (https://www.ulalaunch.com/missions/delta-ii-icesat-2)

Vandenberg Air Force Base, Calif., (Sept. 12, 2018 ) – A United Launch Alliance (ULA) Delta II rocket is in final preparations to launch NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) spacecraft from Space Launch Complex-2 on Sept. 15. This marks the final launch of the Delta II rocket, which first launched on Feb. 14, 1989.

"This is the end of an era, as we prepare to launch the final Delta II rocket," said Gary Wentz, ULA vice president of Government and Commercial Programs. "This vehicle has truly created a legacy throughout its history launching NASA, critical U.S. military satellites and commercial clients."

From its origin as the launch vehicle for the first Global Positioning System (GPS) satellites to NASA's Earth observing, science and interplanetary satellites – including Mars rovers Spirit and Opportunity – to vital commercial communication and imaging satellites, the Delta II rocket has justly earned its place in space history.

ICESat-2, with its single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), will provide scientists with height measurements to create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, forests and more. Northrop Grumman built the spacecraft. In addition to ICESat-2, this mission includes four CubeSats which will launch from dispensers mounted to the Delta II second stage.

This mission will launch aboard a Delta II 7420-10 configuration rocket, which includes a 10-foot-diameter payload fairing (PLF). The booster for this mission is powered by the RS-27A engine and the second stage is powered by the AJ10-118K engine.

To date ULA has a track record of 100% mission success with 129 successful launches.

With more than a century of combined heritage, United Launch Alliance is the nation's most experienced and reliable launch service provider. ULA has successfully delivered more than 125 satellites to orbit that aid meteorologists in tracking severe weather, unlock the mysteries of our solar system, provide critical capabilities for troops in the field and enable personal device-based GPS navigation.

ЦитироватьICESat-2 explained

SciNews (https://www.youtube.com/channel/UCjU6ZwoTQtKWfz1urL7XcbA)

Опубликовано: 12 сент. 2018 г.

NASA's ICESat-2, the Ice, Cloud and land Elevation Satellite-2, will provide critical observations of how ice sheets, glaciers and sea ice are changing. ATLAS (Advanced Topographic Laser Altimeter System), the single instrument on ICESat-2, will measure melting ice sheets and investigate how this effects sea level rise, investigate changes in the mass of ice sheets and glaciers, estimate and study sea ice thickness, and measure the height of vegetation in forests and other ecosystems worldwide.

ЦитироватьICESat-2 orbit

SciNews (https://www.youtube.com/channel/UCjU6ZwoTQtKWfz1urL7XcbA)

Опубликовано: 12 сент. 2018 г.

NASA's ICESat-2 spacecraft is designed to accurately measure land and ice elevations on Earth. ICESat-2 will be in a polar orbit which will provide high coverage near the poles where ice elevations are changing relatively quickly.

Цитировать(https://img.novosti-kosmonavtiki.ru/185344.jpg)NASA_LSP‏Подлинная учетная запись @NASA_LSP (https://twitter.com/NASA_LSP) 40 мин. назад (https://twitter.com/NASA_LSP/status/1040259293608599552)

We are L-2 days until #ICESAT2 (https://twitter.com/hashtag/ICESAT2?src=hash) launches from Vandenberg Air Force Base, Calif. Weather forecast sits @ 100% "go" on launch day. The 40-min launch window begins Sept. 15 @ 5:46am PT (8:46am ET). Watch our prelaunch briefing today @ 1pm PT (4pm ET):
http://nasa.gov/live  (https://t.co/i3n05KPOjU)
#AskNASA (https://twitter.com/hashtag/AskNASA?src=hash)

(https://img.novosti-kosmonavtiki.ru/169330.jpg)

ЦитироватьAbout the ICESat-2 Launch Window

Anna Heiney (https://blogs.nasa.gov/kennedy/author/aheiney/)
Posted Sep 13, 2018 at 11:52 am

(https://img.novosti-kosmonavtiki.ru/130826.jpg) (https://img.novosti-kosmonavtiki.ru/130826.jpg)
The ICESat-2 mission will measure the changing height of Earth's glaciers, ice sheets and sea ice, one laser pulse at a time, 10,000 laser pulses per second. Image credit: NASA

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, is scheduled to launch Saturday, Sept. 15, at 5:46 a.m. PDT (8:46 a.m. EDT). There is a 40-minute launch opportunity within the spacecraft launch window, which extends for 2 hours, 34 minutes. The 40-minute window is determined by super-cold liquid oxygen temperature (cryogenic propellant) effects on the Delta II rocket. The team is targeting the earliest opportunity within the spacecraft window, which could shift based on launch operations.

ЦитироватьICESat-2 Prelaunch Mission Briefing Today

Anna Heiney (https://blogs.nasa.gov/icesat2/author/aheiney/)
Posted Sep 13, 2018 at 1:01 pm

(https://img.novosti-kosmonavtiki.ru/130826.jpg) (https://img.novosti-kosmonavtiki.ru/130826.jpg)
The ICESat-2 mission will measure the changing height of Earth's glaciers, ice sheets and sea ice, one laser pulse at a time, 10,000 laser pulses per second. Image credit: NASA

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2 (https://www.nasa.gov/icesat2), is being prepared for liftoff Saturday aboard a United Launch Alliance Delta II rocket from Space Launch Complex-2 at Vandenberg Air Force Base in California. The launch window opens at 8:46 a.m. EDT (5:46 a.m. PDT).

NASA will host a prelaunch mission briefing today at 4 p.m. EDT (1 p.m. PDT). The briefing will be broadcast on NASA TV (https://www.nasa.gov/live). Scheduled participants are:

[/li]
• Tom Wagner, ICESat-2 program scientist at NASA Headquarters
• Doug McLennan, ICESat-2 project manager at NASA's Goddard Space Flight Center
• Cathy Richardson, Deputy Program Manager, Earth Science Projects Division, NASA Goddard Space Flight Center
• Tom Neumann, ICESat-2 deputy project scientist at Goddard
• Lori Magruder, ICESat-2 science definition team lead at the University of Texas at Austin
• Helen Fricker, ICESat-2 science definition team member at the Scripps Institution of Oceanography
• Bill Barnhart, ICESat-2 program manager at Northrop Grumman
• Tim Dunn, launch director at NASA's Kennedy Space Center
• Scott Messer, program manager for NASA Programs at United Launch Alliance
• 1st Lt. Daniel Smith, launch weather officer with the 30th Space Wing at Vandenberg
  

ЦитироватьICESat-2 Proceeds Toward Launch Sept. 15

Anna Heiney (https://blogs.nasa.gov/icesat2/author/aheiney/)
Posted Sep 13, 2018 at 2:13 pm

(https://img.novosti-kosmonavtiki.ru/130828.jpg) (https://blogs.nasa.gov/icesat2/wp-content/uploads/sites/283/2018/09/ICESat2Logo2017_horiz.jpg)

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, mission and launch teams today concluded a successful Launch Readiness Review. There are no technical issues being worked at this time. Teams are proceeding toward liftoff from California's Vandenberg Air Force Base on Saturday, Sept. 15, at 5:46 a.m. PDT (8:46 a.m. EDT) on a United Launch Alliance Delta II, the rocket's final mission.

ICESat-2 will measure the height of our changing Earth, one laser pulse at a time, 10,000 laser pulses per second. The satellite will carry a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), which measures the travel times of laser pulses to calculate the distance between the spacecraft and Earth's surface. ICESat-2 will provide scientists with height measurements that create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain, including glaciers, sea ice and forests.

The U.S. Air Force 30th Space Wing weather officer indicated that they are predicting a 100 percent chance of favorable weather on launch day.

Цитировать(https://img.novosti-kosmonavtiki.ru/29925.jpg)Michael Baylor‏ @nextspaceflight (https://twitter.com/nextspaceflight) 29 мин. назад (https://twitter.com/nextspaceflight/status/1040345252727586819)

Weather is 100% go for the ICESat-2 launch on Saturday morning. In the event of a scrub, weather remains 100% go for Sunday. However, "patchy fog" will reduce visibility for spectators.

ЦитироватьSpaceX competitor ULA readies for final launch of 30-year-old Delta II rocket

By Eric Ralph (https://www.teslarati.com/author/eric-ralph/)
Posted on September 13, 2018

Long-time SpaceX competitor United Launch Alliance (ULA) is nearly ready for the final launch of its Boeing subsidiary's Delta II family of rockets, culminating a nearly 30-year history mostly dominated by routine success.

If completed without failure, the launch of NASA's ICESat-2 satellite – built to track global ice-sheet variation with a huge space-based laser – will mark Delta II's 100th consecutive success and the rocket's 153rd fully successful launch overall, an immensely impressive and laudable achievement regardless of the vehicle's lack of competitive advantage in the modern launch industry.

Спойлер

Цитировать(https://img.novosti-kosmonavtiki.ru/186040.jpg)Chris B - NSF‏ @NASASpaceflight (https://twitter.com/NASASpaceflight)

A teary farewell to Delta II this weekend, so in the run up we're going to give her a send off with a trip down memory lane per the vehicle's evolution from Thor.

Standby for a 7,000 word (yep!) feature article from William Graham on Thursday, with a ton of cool info/old photos.

(https://img.novosti-kosmonavtiki.ru/169036.jpg)

19:43 (https://twitter.com/NASASpaceflight/status/1040068365082083328) - 12 сент. 2018 г.

Shockingly tiny when compared with modern launch vehicles like Delta IV, Atlas V, and Falcon 9, Delta II measures roughly 39 meters (~128 ft) tall, 2.4 meters (8 ft) in diameter, and weighs 160 metric tons (~350,000 lb) when fully fueled, just over half as tall and significantly less than 30% as heavy as SpaceX's Falcon 9.

[свернуть]

Contracted by NASA in 2013, Delta II's ICESat-2 launch cost the agency roughly $97 million (2013 USD), although the cost of launch has shrunk in relation to the satellite, which suffered at least $200 million of overruns and 12+ months of delays due to difficulties developing the spacecraft's impressive space-based LIDAR system. For comparison, NASA contracted a Falcon 9 launch (for the TESS exoplanet observatory, launched in April 2018 ) from SpaceX for $87 million in 2016, while the USAF has secured several launch contracts with SpaceX for far more complex GPS satellite launches at a cost of almost exactly $97 million apiece.

Спойлер

(https://img.novosti-kosmonavtiki.ru/218903.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-icesat-2-prep-nasa-5/)
The final Delta II rocket is awaiting its last launch from Vandenberg Air Force Base this Saturday. (NASA/Randy Beaudoin)

(https://img.novosti-kosmonavtiki.ru/218905.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-nasa-themis-launch-2007-nasa/)
A Delta II Heavy rocket seen launching NASA's THEMIS satellite in 2007. (NASA)

(https://img.novosti-kosmonavtiki.ru/218908.jpg) (https://www.teslarati.com/spacex-falcon-9-block-5-booster-port-return-fleet-growth/falcon-9-b1049-ocisly-return-091218-tom-cross-8c/)
Falcon 9 Block 5 booster B1049 returned to Port Canaveral today, ~60 hours after launch. Falcon 9 is dramatically cheaper than the aging Delta II. (Tom Cross)

AGING ROCKETS, CHANGING MARKETS

Put simply, the contrast in capabilities offered for equivalent prices soundly demonstrates exactly why Delta II is being phased out. Although capable of better performance with a third upper stage and nine much larger solid rocket boosters (SRBs), that 'Heavy' variant of Delta II cost NASA an incredible $150 million per launch in 2009. For the versions of Delta II closer to $100 million per launch, the rocket is able to place 2500-3200 kg (5500-7000 lb) in low Earth orbit and not much at all to any higher energy destinations, which demand a third stage or a heavier rocket. At a comparable price (or much lower in SpaceX's case), Atlas V and Falcon 9 are able to launch far larger payloads to far higher orbits.

This was by no means the case when Delta II debuted in 1989, and the McDonnell Douglas-built rocket readily earned its impressive reputation as a relatively reliable, capable, and (more or less) affordable launch vehicle compared alongside other rockets available in the '90s. Delta II wound up as a ULA rocket (sort of) thanks to Boeing and McDonnell Douglas' 1997 corporate merger, followed in 2006 by Lockheed Martin and Boeing's cooperative formation of the United Launch Alliance. ULA thus operates Delta II, Delta IV, and Atlas V, all featuring multiple variants and very few distinguishing capabilities when compared amongst themselves.

(https://img.novosti-kosmonavtiki.ru/218902.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-icesat-2-prep-nasa-3/)
Delta II is trucked to the launch pad ahead prior to launch. (NASA)

(https://img.novosti-kosmonavtiki.ru/218904.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-icesat-2-prep-ula-2/)
The business end of Delta II. (ULA)

(https://img.novosti-kosmonavtiki.ru/218900.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-icesat-2-prep-nasa-1/)
ULA technicians install one of four solid rocket boosters on ICESat-2's Delta II launch vehicle. (NASA)

(https://img.novosti-kosmonavtiki.ru/218901.jpg) (https://www.teslarati.com/spacex-competitor-ula-final-launch-30-year-old-rocket/delta-ii-icesat-2-prep-nasa-2/)
ULA technicians install one of four solid rocket boosters on ICESat-2's Delta II launch vehicle. (NASA)
 
The cost of maintaining all those highly duplicative rockets and unique factories and engineering expertise is fundamentally unnatural and reliant upon some sort of noncompetitive market forces (i.e. launch monopolies assured through "block buys" of multiple rockets from NASA and the US military), forces that have been mortally challenged by SpaceX's reintroduction of competition to the American launch industry.

[свернуть]

ICESat-2 is scheduled to launch on Delta II on Saturday, September 15th at 5:46 AM PDT/12:46 UTC. Stay tuned for more information on ICESat-2's giant space LIDAR payload and mission goals, as well as Teslarati photographer Pauline Acalin's photos of the fairly historic rocket launch.

ЦитироватьDelta II ICESat-2 Mission Profile

United Launch Alliance (https://www.youtube.com/channel/UCnrGPRKAg1PgvuSHrRIl3jg)

Опубликовано: 13 сент. 2018 г.

A United Launch Alliance Delta II Heavy rocket will launch NASA's Ice, Cloud and land Elevation-2 (ICESat-2) mission from Vandenberg Air Force Base, California. The ICESat-2 mission will be the final for the workhorse Delta II rocket, which has launched 154 times, including missions for the U.S. Air Force, NASA, the National Reconnaissance Office and commercial customers. Go Delta! Go ICESat-2!

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 17 ч. назад (https://twitter.com/ulalaunch/status/1040308515032711168)

NASA's #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) mission will launch to space aboard a ULA #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) 7420-10 rocket. This 2-stage rocket has 4 solid rocket motors and a 10-foot-diameter composite fairing.

(https://img.novosti-kosmonavtiki.ru/169269.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/29920.jpg)D. Stamos/Helodriver‏ @SpacecoastPix (https://twitter.com/SpacecoastPix) 3 ч. назад (https://twitter.com/SpacecoastPix/status/1040536365107236868)

В ответ @NASASpaceflight (https://twitter.com/NASASpaceflight) @ulalaunch (https://twitter.com/ulalaunch)

A shot that closes the entire Thor Delta circle.

(https://img.novosti-kosmonavtiki.ru/169492.jpg)

ЦитироватьTower Rollback Friday, Live Launch Coverage Saturday

Anna Heiney (https://blogs.nasa.gov/icesat2/author/aheiney/)
Posted Sep 14, 2018 at 9:04 am

(https://img.novosti-kosmonavtiki.ru/130829.jpg) (https://blogs.nasa.gov/icesat2/wp-content/uploads/sites/283/2018/09/ICESat2Logo2017sm_vert.jpg)

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2 (https://www.nasa.gov/content/goddard/icesat-2), a mission to measure the changing height of Earth's ice, is scheduled to launch Saturday, Sept. 15, with a 40-minute window opening at 5:46 a.m. PDT (8:46 a.m. EDT). The spacecraft will lift off from Space Launch Complex 2 (SLC-2) at Vandenberg Air Force Base in California on the final launch of a United Launch Alliance Delta II rocket. The U.S. Air Force 30th Space Wing weather officer reported they are predicting a 100 percent chance of favorable weather on launch day.

Be sure to follow along during the live coverage events below.

NASA EDGE Tower Rollback Show, Friday, Sept. 14, at 6 p.m. PDT (9 p.m. EDT)
Watch live at:
NASA TV: www.nasa.gov/nasalive (http://www.nasa.gov/nasalive)
NASA EDGE Facebook: www.facebook.com/nasaedgefan (http://www.facebook.com/nasaedgefan)
NASA LSP Facebook: www.facebook.com/NASALSP (http://www.facebook.com/NASALSP)
NASA EDGE YouTube: www.youtube.com/NASAedge (http://www.youtube.com/NASAedge)
NASA EDGE Ustream: www.usream.tv/nasaedge (http://www.usream.tv/nasaedge)

Guests:
Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate in Washington
Doug McLennan, ICESat-2 project manager, NASA Goddard Space Flight Center
Kelly Brunt, ICESat-2 science team member, NASA Goddard Space Flight Center
Rex Engelhardt, mission manager, NASA's Launch Services Program
Mic Woltman, chief, Fleet Systems Integration Branch, NASA's Launch Services Program
Tim Dunn, launch director, NASA Kennedy Space Center
Tom Neumann, ICESat-2 deputy project scientist, NASA Goddard Space Flight Center
Donya Douglas-Bradshaw, ATLAS instrument project manager, NASA Goddard Space Flight Center
Dana VanDersaral, mission assurance team, United Launch Alliance

Live Launch Coverage, Saturday, Sept. 15, 5:10 a.m. PDT (8:10 a.m. EDT)
Join us for updates from the countdown, here on the blog and on NASA TV (http://www.nasa.gov/nasalive).

ЦитироватьScientists eager to renew global ice measurements with ICESat 2 mission
September 14, 2018 (https://spaceflightnow.com/2018/09/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

(https://img.novosti-kosmonavtiki.ru/144945.jpg)
Artist's illustration of the ICESat 2 satellite and its six green laser beams designed to measure the height of ice sheets. Credit: NASA

The satellite awaiting launch early Saturday from California aboard the final flight of the venerable Delta 2 rocket should allow scientists to more precisely track changes in our planet's ice sheets, using six green laser beams to chart the height and slope of polar ice and glaciers, providing a key input into climate change research.

Researchers who plan to analyze data from the new satellite say a better understanding of Earth's ice will help them learn about our planet's changing climate, and help predict how melting ice will contribute to rising sea levels.

NASA's $1 billion ICESat 2 mission is set for liftoff at 5:46 a.m. EDT (8:46 a.m. EDT; 1246 GMT) from Vandenberg Air Force Base, a military-run spaceport on California's Central Coast between Los Angeles and San Francisco.

The satellite will ride into an orbit that flies pole-to-pole aboard the final flight of United Launch Alliance's Delta 2 rocket, a workhorse launcher with 154 missions in its pedigree that is now on the verge of retirement.

ICESat 2 stands for Ice, Cloud and land Elevation Satellite 2, a follow-on to NASA's ICESat mission which measured global ice sheets from 2003 until 2009. Equipped with a laser split into six beams, ICESat 2 will fly around 300 miles (500 kilometers) above the planet in an orbit tilted at a 92-degree angle to the equator, giving the mission coverage up to 88 degrees north and south latitude.

Featuring an improved laser instrument designed to provide more precise measurements than its predecessor, ICESat 2 will extend a data series which has shown ice is melting around the edges of Greenland and Antarctica, and is thinning in the oceans.

Спойлер

(https://img.novosti-kosmonavtiki.ru/144735.jpg)
Technicians open and inspect the flight door to ICESat 2's laser instrument shortly after the spacecraft arrived at Vandenberg Air Force Base, California, in June. Credit: USAF 30th Space Wing/Timothy Trenkle

NASA in recent years has continued surveying ice heights with an airborne campaign called Operation Ice Bridge, showing some trends of melting ice detected by the ICESat satellite continued after that mission ended in 2009. But satellites like ICESat provide more uniform coverage.

"What we learned from ICESat about the ice sheets of Greenland and Antarctica is that they are particularly losing ice around coastal areas, which means, one, that they were losing ice, and also two, it was probably tied to changes occuring in the ocean," said Tom Wagner, NASA's cryosphere program scientist.

"With an aircraft, you can't make the same amount of measurements that you can by satellite," Wagner said. "What we found with Ice Bridge is that the changes observed by ICESat are not only continuing, but they appear to be accelerating in some cases."

That's important because ice conditions are linked to other factors that drive Earth's climate, such as currents and temperatures in the oceans. And rising sea levels could threaten cities along coastlines.

"In Antarctica and Greenland, we have about two-thirds of the Earth's fresh water," said Helen Fricker, a member of ICESat's science definition team at the Scripps Institution of Oceanography. "If all of that ice melted, we would raise global sea level on average by about 180 feet (54 feet), which is very significant."

Altimetry data collected by by the U.S.-French TOPEX/Poseidon and Jason series of satellites show the average global sea level rose by 77 millimeters (3 inches) from 1993 through 2017.

(https://img.novosti-kosmonavtiki.ru/144970.jpg)
Artist's illustration of the ICESat 2 satellite. Credit: NASA

"ICESat 2 really is a revolutionary new tool for both land ice and sea ice research," said Tom Neumann, ICESat 2's deputy project scientist at NASA's Goddard Space Flight Center.

NASA has used satellites to look at ice for decades, but tracking ice coverage is easier than measuring the height, and estimating the thickness, of floating sea ice and ice caps covering land masses like Antarctica and Greenland.

Rather than relying on a single laser beam, as ICESat did, the new mission will fire six laser beams down to Earth and measure the time it takes for the light to bounce off the surface and back to a telescope on-board the spacecraft.

"To measure, or to estimate, the thickness of sea ice, ICESat 2 measures the height of the sea ice floating in the ocean and compares it with the height of the ocean water in cracks in the sea ice," Neumann said. "By comparing these two elevations, we can calculate the height of the sea ice sticking up out of the ocean water."

Only about a tenth of total sea ice sticks out above the ocean water line, so scientists can use ICESat 2's raw measurements to get a handle on the total thickness of the ice floating in the seas. Then scientists will use the ice height information in concert with gravity measurements from space using the GRACE Follow-On mission, which launched in May and helps scientists estimate the mass of the ice.

The ICESat 2 satellite was built by Northrop Grumman Innovation Systems, and its single instrument — the Advanced Topographic Laser Altimeter System, or ATLAS — was developed at NASA's Goddard Space Flight Center.

"ATLAS essentially acts like a stop watch," said Donya Douglas-Bradshaw, ATLAS instrument manager at Goddard. "The ATLAS laser fires 10,000 pulses per second with a trillion photons in each shot. Each time the laser fires, it starts the stop watch. It takes about 3.3 milliseconds for the beam to exit the instrument, reach the surface and return back to the telescope."

Only about a dozen or so photons will make it back to ICESat 2's receiving telescope, with the rest of the light scattering in the atmosphere or back into space.

The laser package "has the ability to time tag a single photon to billionth of a second accuracy," Douglas-Bradshaw said in a briefing with reporters. "This precision allows the instrument to detect annual changes in ice elevation on the order of half of a centimeter (0.2 inches)."

The photon-counting method is new, and development the ATLAS laser proved to be a challenge, delaying ICESat 2's launch more than two years, and adding several hundred million dollars to the mission's cost.

"The original ICESat mission went up, and the scientists looked at the data. They were very excited about that, and they came forward, and they said this mission has to do a lot of better things," said Doug McLennan, ICESat 2's project manager at Goddard. "This put the challenge to the engineering team to design a mission that could accmoplish those things. It was a very challenging mission to come up with the ATLAS instrument. It took longer than we thought, but now everything is buttoned up and sitting on top of that rocket and ready to go."

ICESat 2's ATLAS instrument actually includes two lasers, with a primary and a redundant emitter, and the pulses go through a diffractive optics element that splits the light into six green beams — each at a wavelength of 532 nanometers — spread across a swath of about 4 miles (6 kilometers) along the satellite's ground track.

The lasers will travel from the spacecraft down to Earth in pairs, each separated by about 300 feet (90 meters) to provide measurements of the average slope of ice. With 10,000 pulses per second — up from the 40 laser shots per second on the original ICESat mission, the ATLAS instrument will take a height measurement along its track at intervals of every 2.3 feet (70 centimeters) as the satellite travels at approximately 17,000 mph (27,000 kilometers per hour).

As ICESat 2 flies around the planet every hour-and-a-half, the Earth will rotate underneath the satellite's orbit, allowing the mission to measure global ice heights.

"We have an orbit that is an exact repeat of itself every 91 days," McLennan said. "That means we see the same piece of ice every three months. Every season, we get to measure what's happening on that piece of ice, and that allows us to accumulate a dataset year-over-year, from each season to the next."

The ICESat 2 satellite weighs around 3,340 pounds (1,515 kilograms) at launch, according to McLennan.

McLennan said the spacecraft has enough fuel to operate more than 10 years. ICESat 2's primary mission is scheduled for three years, but could be extended.

Scientists working in other Earth science disciplines will also get results from ICESat 2.

"ICESat 2 never turns off," said Lori Magruder from University of Texas at Austin, who led the mission's science definition team. "It operates all the time, so you get measurements over every single surface.

"We get measurements over the open ocean, and we also get measurements over inland water bodies," she said. "This is important because we don't have global measurements that can tell us about our Earth's reservoirs, so that informs certainly our knowledge of our planet's water storage."

The laser ranging instrument on ICESat 2 will also reveal new information about cloud structure as laser photons reflect back to the satellite, and the mission should also provide estimates of the heights of forests.

"From the vantage point of space, we'll get a global tree height measurement," Magruder said. "That allows us to create a global biomass estimate. Biomass is important becaause that informs our knowledge of the carbon cycle, and how that contributes to our environment and the climate."

[свернуть]

ЦитироватьNASA EDGE Live Stream

NASA EDGE (https://www.youtube.com/channel/UCEPgFeclBHqZp80D14J5kfA)

Трансляция началась 16 минут назад

ЦитироватьLive coverage: Final Delta 2 rocket set for launch from California
September 14, 2018 (https://spaceflightnow.com/2018/09/) / Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

Updated: 09/15/2018 01:07 Stephen Clark

Launch preparations this week have gone like clockwork, according to NASA and United Launch Alliance Officials preparing for the Delta 2's final flight.

Last Friday, officials convened for a flight readiness review and agreed to proceed with the mission as scheduled. On Monday and Tuesday, ground crews working at Space Launch Complex 2-West, the Delta 2's launch pad at Vandenberg Air Force Base, loaded the rocket's second stage with its propellant supply of Aerozone 50 fuel, made by mixing hydrazine and unsymmetrical dimethyl-hydrazine, and nitrogen tetroxide oxidizer.

The toxic propellants will feed the second stage's Aerojet Rocketdyne AJ10 engine during four burns planned on Saturday's mission to carry NASA's ICESat 2 satellite and four tiny CubeSats into orbit.

The launch team also conducted a mission dress rehearsal Tuesday to practice countdown procedures, followed by final closeouts of the Delta 2 rocket, final conditioning of the ICESat 2 satellite's battery, and preparations for rollback of the launch pad's mobile gantry this evening.

Officials met again Thursday for a launch readiness review and determined all systems are "go" to begin the final countdown.

The mobile gantry at the SLC-2W launch pad overlooking the Pacific Ocean is scheduled around 6:45 p.m. PDT (9:45 p.m. EDT).

Цитировать09/15/2018 01:20 Stephen Clark

Weather forecasters don't expect conditions along California's Central Coast will stand in the way of the Delta 2 rocket's climb into orbit early Saturday, but spectators in the area hoping to glimpse the launch might be thwarted by clouds and fog.

The marine layer that typically blankets the coastline at Vandenberg Air Force Base is forecast to be in the area during Saturday's launch window, which opens at 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT) and extends until 8:20 a.m. PDT (11:20 a.m. EDT; 1320 GMT).

Forecasters predict overcast clouds at about 1,000 feet, patchy fog with visibility around 2 or 3 miles, northerly winds of 10 to 15 knots, and a temperature between 52 and 57 degrees Fahrenheit.

There is a 0 percent chance weather will violate any the Delta 2's launch criteria, according to the official Air Force launch weather forecast.

Цитировать(https://img.novosti-kosmonavtiki.ru/29931.jpg)Tory Bruno‏Подлинная учетная запись @torybruno (https://twitter.com/torybruno) 3 ч. назад (https://twitter.com/torybruno/status/1040681713658200064)

Weather still looks good. Let's go to space.
#ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)

(https://img.novosti-kosmonavtiki.ru/169557.jpg)

ЦитироватьICESat-2 Weather Remains Favorable for Launch

Stephanie Martin (https://blogs.nasa.gov/icesat2/author/samarti9/)
Posted Sep 14, 2018 at 8:58 pm

Weather remains favorable for the Sept. 15 launch of NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) from Vandenberg Air Force Base in California on a United Launch Alliance Delta II rocket. The latest forecast from the U.S. Air Force 30th Space Wing predicts a 100 percent chance of favorable weather on launch day with patchy fog and visibility of 2-3 miles.

The spacecraft window opens at 5:46 a.m. PDT (8:46 a.m. EDT) and extends for 2 hours, 34 minutes.

The launch vehicle window is now approximately 50 minutes based on the launch team's decision to load RP-1 fuel during the countdown, approximately 2 hours and 40 minutes prior to the beginning of the launch window.

Цитировать(https://img.novosti-kosmonavtiki.ru/184891.jpg)April Smith‏ @performinginedu (https://twitter.com/performinginedu) 17 мин. назад (https://twitter.com/performinginedu/status/1040780508680994816)

What a beautiful sight! #icesat2 (https://twitter.com/hashtag/icesat2?src=hash) #delta2 (https://twitter.com/hashtag/delta2?src=hash) #NASAsocial (https://twitter.com/hashtag/NASAsocial?src=hash)

(https://img.novosti-kosmonavtiki.ru/170057.jpg)


(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 1 мин. назад (https://twitter.com/ulalaunch/status/1040783674369662976)

Sun setting behind Space Complex-2 at Vandenberg AFB as we prepare to roll the tower back from the #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) with #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)

(https://img.novosti-kosmonavtiki.ru/170043.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/67516.jpg)Jonathan McDowell‏Подлинная учетная запись @planet4589 (https://twitter.com/planet4589) 9 мин. назад (https://twitter.com/planet4589/status/1040781153622470656)

NASA's ICESAT-2 is scheduled for launch tomorrow morning on the final Delta 2 rocket, a Delta 7420-10 model to be launched by @ulalaunch (https://twitter.com/ulalaunch) from Space Launch Complex 2-West at Vandenberg AFB


5 мин. назад (https://twitter.com/planet4589/status/1040782492645699584)

Delta flight 381 will also deploy four cubesats: @UCLA (https://twitter.com/UCLA)'s ELFIN and ELFIN-STAR; @PolySat (https://twitter.com/PolySat)'s CP7 DAVE; and @ucf (https://twitter.com/UCF)'s confusingly named SurfSat (no relation to the SurfSat launched by NASA/JPL/CalTech in 1995)

ЦитироватьUCLA sends student-built satellite into space

UCLA (https://www.youtube.com/channel/UCPpw6jRIL1B9nU0k7-GujOQ)

Опубликовано: 11 сент. 2018 г.

During the last five years nearly 250 students have spent thousands of hours designing and building ELFIN, more formally the Electron Losses and Fields Investigation CubeSat.

ЦитироватьSept. 14, 2018

NASA-funded ELFIN To Study How Electrons Get Lost

Three hundred and ten miles above our planet's surface, near-Earth space is abuzz with action. Here begin the Van Allen Belts, a pair of concentric rings of fast-moving particles and intense radiation that extends more than 30,000 miles farther into space. For the most part these particles are confined to this special region, spiraling along Earth's magnetic field lines. But sometimes they come too close and crash into our atmosphere — creating the eye-catching diffuse red aurora, but also potentially interfering with critical communications and GPS satellites that we depend on every day.

(https://img.novosti-kosmonavtiki.ru/207717.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/elfinscienceradiationbeltparticles.jpg)
An artist's depiction of the Van Allen Belts, showing Earth's magnetic field lines and the trajectories of charged particles trapped by them. The twin ELFIN spacecraft are shown following their inclined polar orbit, traced in yellow.
Credits: UCLA EPSS/NASA SVS

A new CubeSat mission called The Electron Losses and Fields Investigation, or ELFIN, will study one of the processes that allows energetic electrons to escape the Van Allen Belts and fall into Earth. ELFIN is set to launch from the Vandenburg Air Force Base in California on Sept. 15, 2018.

Спойлер

When magnetic storms form in near-Earth space, they create waves that jiggle Earth's magnetic field lines, kicking electrons out of the Van Allen Belts and down into our atmosphere. ELFIN aims to be the first to simultaneously observe this electron precipitation while also verifying the causal mechanism, measuring the magnetic waves and the resulting "lost" electrons.

https://www.youtube.com/watch?v=686ouucfzVw (https://www.youtube.com/watch?v=686ouucfzVw)
(video (https://www.youtube.com/watch?v=686ouucfzVw) 4:46)
During the last five years nearly 250 students have spent thousands of hours designing and building ELFIN, more formally the Electron Losses and Fields Investigation CubeSat.
Credits: UCLA

(https://img.novosti-kosmonavtiki.ru/208338.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/elfin2xflightunits.jpg)
The twin ELFIN CubeSats.
Credits: UCLA EPSS

Funded by NASA, The National Science Foundation, and industry partners, ELFIN is a CubeSat mission. CubeSats are small and lightweight satellites, measured in standardized 10-by-10-by-10 cubic centimeter units, that are comparatively quick to develop and come with a price tag at a fraction of larger satellite missions. ELFIN uses two identical 3U, or 3 cubic unit, CubeSats — both about the size of a loaf of bread. By using two satellites instead of one, ELFIN will be able to measure how the precipitated electrons vary across space and time. Designed, built and tested by a team of 250 UCLA students over five years, ELFIN will be the first satellite developed, managed and operated entirely by UCLA. A key advantage of CubeSats is that they allow an inexpensive means to engage students in all phases of satellite development, operation and exploitation through real-world, hands-on research and development experience.

Small satellites, including CubeSats, are playing an increasingly larger role in exploration, technology demonstration, scientific research and educational investigations at NASA. These miniature satellites provide a low-cost platform for NASA missions, including planetary space exploration; Earth observations; fundamental Earth and space science; and developing precursor science instruments like cutting-edge laser communications, satellite-to-satellite communications and autonomous movement capabilities.

On launch day, ELFIN will hitch a ride as a secondary payload on a Delta II rocket with NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2 mission. ICESat-2 will measure the thickness of ice sheets, glaciers, sea ice and more to document how Earth's cryosphere — the frozen water part of the Earth system — is changing over time.

By Miles Hatfield (mailto:miles.s.hatfield@nasa.gov)
NASA's Goddard Space Flight Center (http://nasa.gov/goddard), Greenbelt, Md.

[свернуть]

Last Updated: Sept. 14, 2018
Editor: Rob Garner

ЦитироватьSept. 13 -- LRR completed

Preparations are underway for the United Launch Alliance Delta II rocket's sentimental sendoff into retirement after 29 years of service to the U.S. Air Force, NASA, the National Reconnaissance Office and commercial customers.

Saturday's launch is scheduled for 5:46 a.m. PDT (8:46 a.m. EDT; 1246 UTC) from Space Launch Complex-2 at Vandenberg Air Force Base in California. The mission will deliver NASA's second Ice, Cloud and land Elevation Satellite, or ICESat-2, environmental spacecraft into a polar orbit to precisely measure the changing height of Earth's ice sheets in unprecedented detail.

We will provide live updates throughout the countdown and flight on this page starting at 2:30 a.m. PDT (5:30 a.m. EDT; 0930 UTC).

The Launch Readiness Review was completed earlier today. The meeting, chaired by NASA Launch Manager Tim Dunn, confirmed the readiness of the launch vehicle, payload and mission assets for entering the countdown.

The launch weather forecast, according the 30th Weather Squadron at Vandenberg, calls for a deck of low stratus clouds at 1,000 feet and high cirrus at 30,000 feet, visibility of 2-3 miles with fog, northerly winds of 10 to 15 knots and a temperature of 52 degrees F. There is a zero percent chance of a weather rule violation.

This will be the 155th flight by the Delta II rocket since its debut on Feb. 14, 1989. The lasting legacy of the Delta II extends from the Global Positioning System that revolutionized modern navigation on Earth to the exploration of the Martian surface with the Mars rovers Spirit and Opportunity.
...

ЦитироватьSept. 14 -- Coverage begins early tomorrow!

Welcome to our Live Launch Updates Blog, bringing you official and timely information during countdowns to liftoff.

Join us early tomorrow morning for live reports throughout the Delta II rocket's countdown to the ICESat-2 launch from Vandenberg Air Force Base in California. Our automatically-refreshing blog -- coming to you from Vandenberg's launch control center -- will begin on this page at 2:30 a.m. PDT (5:30 a.m. EDT; 0930 UTC) prior to the countdown starting.

Liftoff of the final Delta II rocket is scheduled for 5:46 a.m. PDT (8:46 a.m. EDT; 1246 UTC).

For a preview of what to expect after liftoff, see our Mission Profile video (https://youtu.be/QmdXxLlF3Os).

Цитировать(https://img.novosti-kosmonavtiki.ru/29925.jpg)Michael Baylor‏ @nextspaceflight (https://twitter.com/nextspaceflight) 9 мин. назад (https://twitter.com/nextspaceflight/status/1040788815001145350)

MST rollback for #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) with #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) is running 45 minutes behind schedule. This will not impact tomorrow's launch. (via @KSpaceAcademy (https://twitter.com/KSpaceAcademy))


28 мин. назад (https://twitter.com/nextspaceflight/status/1040790670049460225)

@DaneDrefke (https://twitter.com/DaneDrefke) explains that a ground equipment issue was the cause of the delay. The problem has been resolved and will not affect the launch.

Цитировать(https://img.novosti-kosmonavtiki.ru/186263.jpg)Marina Jurica‏ @MJuricaCBS47 (https://twitter.com/MJuricaCBS47) 34 мин. назад (https://twitter.com/MJuricaCBS47/status/1040796293474340864)

Incredible sunset of ⁦@ulalaunch (https://twitter.com/ulalaunch)⁩ #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) carrying ⁦@NASAGoddard (https://twitter.com/NASAGoddard)⁩ #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) satellite into orbit tomorrow morning! Watch for my coverage ⁦@CBS47 (https://twitter.com/CBS47)⁩ at 11pm tonight!
#GoICESat2 (https://twitter.com/hashtag/GoICESat2?src=hash)

(https://img.novosti-kosmonavtiki.ru/170049.jpg)

Цитировать11:35 p.m. PDT (0635 UTC)

Retraction of the Mobile Service Tower from around the Delta II rocket began at 11:34 p.m. PDT (2:34 a.m. EDT; 0634 UTC).

Цитировать11:48 p.m. PDT (0648 UTC)

The 177-foot-tall Mobile Service Tower at Space Launch Complex-2 has been retracted to its launch position, revealing the United Launch Alliance Delta II rocket for its morning liftoff to deliver NASA's ICESat-2 laser altimetry spacecraft into orbit to measure the ebbs and flows of Earth's polar ice.

The MST is a critical part of the launch complex, proving the primary access and weather protection to the rocket during its stay on the launch pad, and the overhead crane system serves a vital role in vertical integration of the rocket elements and payload.

Rollback of the MST signals a major milestone in the early portion of launch day operations. Configuring launch pad systems and securing equipment will be completed over the next few hours before all personnel clear the site for fueling.

Цитировать(https://img.novosti-kosmonavtiki.ru/185967.jpg)NASA_EDGE‏ @NASA_EDGE (https://twitter.com/NASA_EDGE) 3 ч. назад (https://twitter.com/NASA_EDGE/status/1040852630459826176)

We have Tower Rollback!

(https://img.novosti-kosmonavtiki.ru/170062.jpg)

Цитировать2:30 a.m. PDT (0930 UTC)

Fr om Vandenberg Air Force Base in California, this is Delta Launch Control at T-minus 2 hours, 30 minutes and holding.

We are just over three hours away from liftoff of the final United Launch Alliance Delta II rocket, a venerable industry workhorse for nearly 30 years. This will be the 155th and last flight of the beloved rocket that was developed to launch the Global Positioning System, enabled exploration of Mars and served the medium-class space launch market with distinction.

Today's liftoff is scheduled for 5:46 a.m. PDT (8:46 a.m. EDT; 1246 UTC) from Space Launch Complex-2 at Vandenberg Air Force Base on a 53-minute ascent to deploy NASA's ICESat-2 environmental satellite into polar orbit to observe the changes of planet Earth.

The countdown is being orchestrated from the Remote Launch Control Center, located about six miles from the pad, wh ere ULA Launch Conductor Scott Barney and his team will soon initiate the countdown sequence for the Delta II rocket's bittersweet flight into retirement.

Down the hall in the Mission Director's Center, senior managers, including ULA Launch Director Tom Heter and NASA Launch Manager Tim Dunn, provide guidance to the team throughout today's operation.

Activities began last evening when the Mobile Service Tower at the SLC-2 pad was rolled back to the launch position, revealing the 132-foot-tall Delta II for its flight into space. The gantry-like structure was integral in the assembly of the rocket elements and hoisting the ICESat-2 spacecraft into position atop the launcher.

Hands-on work to prepare pad systems, put the infrastructure into the proper configuration and arm the vehicle was completed over the last several hours, leading to a pad-clear status for all personnel...minutes ago.

We are standing by to enter into the count at 2:46 a.m. from the T-minus 2 hour, 30 minute mark. There are two built-in holds at T-minus 15 minutes and T-minus 4 minutes, with durations of 20 minutes and 10 minutes, respectively.

At T-minus 2 hours, 30 minutes and holding, this is Delta Launch Control.

Цитировать(https://img.novosti-kosmonavtiki.ru/186040.jpg)Chris B - NSF‏ @NASASpaceflight (https://twitter.com/NASASpaceflight) 6 ч. назад (https://twitter.com/NASASpaceflight/status/1040806153373069312)

FEATURE ARTICLE:
Delta II to conclude an amazing legacy with ICESat-2 launch

https://www.nasaspaceflight.com/2018/09/delta-end-legacy-icesat-2-launch/ ... (https://t.co/NgRSfTs9SX)

- By William Graham. Current lead photo by Jay L. DeShetler (@jdeshetler (https://twitter.com/jdeshetler))

(https://img.novosti-kosmonavtiki.ru/170053.jpg)

Спойлер

(https://img.novosti-kosmonavtiki.ru/170054.jpg)
(https://img.novosti-kosmonavtiki.ru/170055.jpg)
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[свернуть]

ЦитироватьEngineers say goodbye to society-changing Delta 2 rocket
September 14, 2018 (https://spaceflightnow.com/2018/09/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

(https://img.novosti-kosmonavtiki.ru/144953.jpg)
Michael Freilich, head of NASA's Earth science division, signs a star decal on the side of the Delta 2 rocket. ULA added 167 stars to the rocket, each containing up to five signatures from engineers, retirees and customers who worked on the Delta 2 rocket. Credit: NASA

When the first Delta 2 rocket took off on Valentine's Day 1989, ideas like navigating by smartphone and driving robots on Mars were science fiction. More than 150 launches over the last 30 years helped change all that.

The Delta 2 era is set to close Saturday with the launch of NASA's ICESat 2 Earth-observing satellite from Vandenberg Air Force Base, California, ending a program that was conceived in the Cold War and traces its technological lineage to the dawn of the Space Age.

Liftoff is scheduled for 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT) Saturday, and the launch window extends until 8:20 a.m. PDT (11:20 a.m. EDT; 1520 GMT).

Спойлер

Hundreds of Delta team members and retirees from United Launch Alliance, NASA and other companies involved in the rocket's storied history gathered Thursday evening for a feast of Santa Maria style tri-tip barbecue, reuniting a group that has helped launch many of the Delta 2 flights since 1989.

Many engineers in recent weeks have counted up how many Delta 2 missions they've worked on. Many of the senior managers now at ULA and NASA's Launch Services Program, which oversees the agency's robotic satellite launches, can trace their Delta 2 careers back to the 1980s and 1990s.

Chuck Dovale, deputy manager of the Launch Services Program, says the Delta 177 mission in 1984 was one of his first missions at Hangar AE, home to the mission director's center at Cape Canaveral. That predates the Delta 2 program, which continued the tradition of number flights sequentially..

"That was back back when (NASA) still owned the launch pads," Dovale said. "So it didn't necessarily have to be a NASA satellite flying. We still owned the rockets and the launch pad. We launched for the Navy. We launched many of the commercial missions. One of my first ones was NATO 3D — Delta 177.

"Unfortunately, shortly after that, there was a GOES (weather satellite) on a Delta in May of '86 that failed," Dovale said. "That was a bad year for launches. I probably never learned more in a shorter period of time than after that failure."

The loss of a GOES weather satellite in May 1986 came less than four months after the Challenger accident, which grounded the space shuttle fleet just as the U.S. government began shifting more military launches to the NASA space plane. In the aftermath of the Challenger accident, the Air Force funded development of an upgraded version of the Delta rocket, which became the Delta 2, to ensure military satellites like GPS navigation craft had a ride into space.

(https://img.novosti-kosmonavtiki.ru/143823.jpg)
The penultimate flight of a Delta 2 rocket last year launched NOAA's JPSS 1 weather satellite. Credit: Alex Polimeni/Spaceflight Now

Dovale later became a NASA launch director, managing numerous Delta 2 flights carrying the agency's science probes before moving into a leadership role at the Launch Services Program.

Tim Dunn will serve as NASA's launch director for Saturday's mission, 22 years after joining the Delta 2 program with Boeing, which merged its launcher division with Lockheed Martin's in 2006 to form ULA. The builders of the Delta rocket family changed names through multiple corporate mergers and acquisitions, beginning with the Douglas Aircraft Company, then succeeded by McDonnell Douglas and Boeing before ULA.

The first launch of a Delta rocket occurred in May 1960, debuting a derivative of the Thor intermediate range ballistic missile capable of putting a satellite into orbit. Engineers have lengthened the Thor's original 8-foot-diameter (2.4-meter) first stage several times, expanding the Delta's propellant capacity, while adding a new upper stage engine and strap-on slid rocket boosters to haul heavier payloads into space.

The Delta rocket line has been on the brink of retirement several times, perhaps most notably in the 1980s, when the U.S. government sought to transition all of its satellite launches to the space shuttle. That policy changed in the aftermath of the Challenger accident in 1986, resulting in the creation of the Delta 2 and the restart of the Delta production line.

"Delta has such a rich history, starting back in 1960," Dunn told Spaceflight Now. "If you talk to real gray-beards on the program, it was on death's door step probably at least three, maybe four times, when everyone thought for sure that was the last launch ever, and they were all out of jobs, and somehow it kept getting new life.

"For this version of Delta, we are certain that this one will not fly after ICESat 2," he said.

After stints as an Air Force as a GPS satellite analysis officer and a Titan 4 launch controller, Dunn joined the Delta 2 program supporting dozens of missions as a launch-day guidance engineer. One of his first missions on the Delta 2 rocket was the launch of Mars Pathfinder in December 1996, which delivered NASA's first rover to the red planet.

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A Delta rocket launches from Cape Canaveral in 1962 with the Telstar 1 satellite. Credit: NASA

"One of our first missions was the Mars Pathfinder mission," Dunn said. "That was the very small rover that we sent to Mars back in the fall of '96. That one was really satisfying to me because it was super-cool deep space mission with NASA, our customer at the time ... We were sending something to crawl around on the surface of Mars."

Hot Wheels produced a toy version of Mars Pathfinder's Sojourner rover before the mission's launch.

"My son was just a couple of years old, so it something I could relate to him with toys," Dunn said. "So Pathfinder sticks out."

Dunn joined NASA in 2000, rising in the ranks to be assigned his first mission as launch director in 2011, the final flight of a Delta 2 from Cape Canaveral.

"Just like Tim, I grew up with Delta 2," Dovale said. "It's always been a favorite of mine. It's sad to see it go. It'll be nice to see ICESat 2 successfully launched, but it's going to be bittersweet."

Some engineers go even further back with Delta, which has launched 380 times in its multiple variants.

One 82-year-old avionics advisor who participated in the launch readiness review Thursday worked his first Delta mission — Delta 33 — in 1965, Dunn said.

The more powerful Delta 4 rocket will continue flying for ULA, taking the Delta name into the 2020s, but it is also due for retirement in the early-to-mid-2020s.

The Delta 4 is a new design, incorporating different hydrogen-fueled engines, and wider propellant tanks than the Delta 2. Boeing, which ran the Delta program in the late 1990s, designed the Delta 3 rocket as a bridge between the older a new members of the Delta family, utilizing the Delta 2's Thor-based first stage and the Delta 4's new upper stage.

Delta 2s, which sometimes lifted off two or three times per month in the 1990s and 2000s, have been replaced by a fleet of bigger launchers. ULA moved on to focus on the Atlas 5 and Delta 4 boosters, and SpaceX's Falcon 9 rocket now carries up many of the same types of payloads that were once tailored for the Delta 2.

Many commercial and military missions once served by satellites sized to fly on the medium-lift Delta 2 launcher are now accomplished by smaller spacecraft, taking advantage of the miniaturization trend in technology. At the opposite end of the mass spectrum, many commercial communications satellites outgrew the Delta 2's capabilities in the 1990s and 2000s.

In its configuration with nine solid rocket boosters, a Delta 2 could put more than 6,600 pounds (3,000 kilograms) of payload to an orbit 517 miles (833 kilometers) above Earth.

Delta 2 rockets successfully launched 48 satellites for the U.S. Air Force's Global Positioning System from 1989 through 2009, a two-decade span during which the satellite network became a part of the everyday lives of billions of people worldwide.

"Supporting the Air Force through all those years, that's a special memory with GPS," Dunn said. "From 1989 when GPS 2-1 first launched, as you progressed through the '90s, that was the time when GPS went from this military system that only the military used, to essentially a common everyday person's utility. That was really fun to be supporting and sustaining the constellation that everyone was beginning to use. Fast forward to 2018, and (when) you talk to younger kids today about GPS, they can't imagine life without GPS, on your phone, on your watch, in your car."

The GPS fleet consists of more than 30 satellites, and more than half of the GPS spacecraft currently in orbit were launched by Delta 2s. The network is vital for civilian navigation, from families on road trips, to hikers, to airliners landing in low visibility.

"Every single person who turns on their map on their telephone to get around, that GPS constellation is pretty amazing," said Scott Messer, ULA's Delta 2 program manager. "The constellation itself is super-amazing, but it's certainly been a thrill from the Delta 2's standpoint to launch that and be part of what enabled that."

Messer's first mission with the Delta 2 program was Delta 230

"The Delta 2 vehicle has touched the life of probably every single person in America in the technoloy that it's enabled over its 30 years," Messer said. "It's been a very, very prominent part of space history."

Other Delta 2s dispatched NASA's first three Mars rovers — Sojourner, Spirit and Opportunity — toward the red planet, along with the MESSENGER mission to orbit Mercury, the Dawn mission to the asteroid belt, the Spitzer Space Telescope, the planet-hunting Kepler observatory, weather satellites, and dozens of commercial and military communications spacecraft.

From Vandenberg, Delta 2 rockets hauled the bulk of Iridium's first-generation fleet of voice and data relay satellites into low Earth orbit on 12 launches from 1997 through 2002. Those satellites are now being replaced by an upgraded Iridium fleet launching on SpaceX Falcon 9 rockets.

The Globalstar satellite network, also designed for mobile communications, was deployed by a series of Delta 2 rockets launched from Cape Canaveral.

Of the 154 Delta 2 missions launched to date, 44 have originated from Vandenberg, a spaceport situated on California's Central Coast northwest of Los Angeles suited for launches into polar orbits, a perch preferred by many Earth-observing satellites.

"A number that's even more exciting for me is when you consider the number of successful launches we've had on Delta 2, we've had 99 consecutive successful launches, and ICESat 2 will be No. 100," Messer said.

The streak of successful missions dates back to 1997, when a Delta 2 rocket suffered one of the more memorable launch accidents of the last quarter-century, exploding 13 seconds after liftoff from Cape Canaveral.

The Delta 2 set to launch ICESat 2 will be propelled by a kerosene-burning first stage Aerojet Rocketdyne RS-27A main engine, four strap-on solid rocket boosters supplied by Northrop Grumman, and a restartable second stage AJ10-118K engine, also from Aerojet Rocketdyne The target for the ICESat 2 mission: A roughly circular polar orbit around 300 miles (500 kilometers) above Earth.

"The Delta 2 will go down in history as one of the world's most successful launch vehicles, and we're proud to be part of that legacy," said Eileen Drake, Aerojet Rocketdyne's CEO and president.

The RS-27A main engine, which generates 200,000 pounds of thrust at sea level, is a descendant of the H-1 engine used on the main stages of NASA's Saturn 1 and Saturn 1B rockets, the predecessors of the Saturn 5 moon rocket in the Apollo program. In addition to a main thrust chamber, the RS-27A has two vernier engines for roll control during flight.

The second stage's AJ-118K engine has its roots in the ballistic missile programs of the 1950s, according to Aerojet Rocketdyne. It a combination of Aerozine 50, a fuel cocktail made by mixing hydrazine and unsymmetrical dimethyl-hydrazine, and nitrogen tetroxide oxidizer to provide 9,850 pounds of thrust at altitude.

"This final Delta 2 launch will mark the 241st flight of the RS-27 and the 277th flight of the AJ10; all delivering 100 percent reliability to ensure mission success for our customers," Drake said in a statement. "This outstanding track record represents the hard work and dedication of generations of Aerojet Rocketdyne employees over the decades."

Elizabeth Jones, Aerojet Rocketdyne's RS-27 and AJ10 program manager, said Friday that the Delta 2's engines went through several upgrades over the decades, adding thrust and performance as the rocket's size crew larger. Both types of engines will not fly again after Saturday's mission, but a similar engine to the AJ10 will continue launching with NASA's Orion crew capsule.

"We've been saying at some of our meetings, who's going be the first one to crack? Is anybody going to tear up? It's an emotional time, there's a long legacy to be proud of," Jones said.

"I'll miss the work, I'll miss the people," said Latanjia Robinson, Aerojet Rocketdyne's AJ10 chief engineer. "I'll miss traveling to the launch sites to support the various tasks prior to launch, and the launches themselves. But it'll be rewarding. I look forward to a successful mission.

"I'm getting emotional here thinking about it, but it'll be kind of bittersweet to see the end of such a tremendous program that had such a big impact on our society as a whole," Robinson said in an interview.

Robinson counts Delta 228 — a Delta 2 launch from Florida in 1995 with the Koreasat 1 communications satellite — as her first mission in the launch control center. She will be in the control again during Saturday's countdown, tracking temperatures and pressures in the AJ10 engine before liftoff.

Jones said her first Delta 2 launch in the control center was Delta 305, launch from Florida in 2004 with a GPS navigation payload.

The Delta 2 could fly with three, four or nine solid rocket motors built by Northrop Grumman Innovation Systems, formerly known as Orbital ATK. Over the history of the program, more than 1,000 of the solid motors have launched with Delta 2 rockets.

[свернуть]

Цитировать2:46 a.m. PDT (0946 UTC) – Countdown begins

The countdown has been initiated for today's Delta II rocket launch of NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) mission that will track the changing Earth below.

The next three hours will see the rocket's guidance system activated and tested, the helium and nitrogen systems on the vehicle pressurized, kerosene and super-cold liquid oxygen loaded into the first stage and engine nozzle steering checks conducted. Those are the key highlights leading to our target liftoff time of 5:46 a.m. PDT (8:46 a.m. EDT; 1246 UTC).

ЦитироватьNASA EDGE: ICESat-2 Tower Rollback Show

NASA EDGE (https://www.youtube.com/channel/UCEPgFeclBHqZp80D14J5kfA)

Трансляция началась 9 часов назад

NASA EDGE provides live coverage of the scheduled Tower Rollback for the historic Delta II carrying ICESat-2 and ELaNa 18.

ЦитироватьComing Up at 8:10 a.m. Eastern: Live Coverage of the ICESat-2 Launch

NASA (https://www.youtube.com/channel/UCLA_DiR1FfKNvjuUpBHmylQ)

Опубликовано: 14 сент. 2018 г.

It's the night before launch, so set your alarms! Watch NASA TV Sat., Sept. 15 at 8:10 a.m. EDT (5:10 a.m. Pacific, 12:10 p.m. UTC) for live coverage of the liftoff of NASA's ICESat-2 mission aboard a United Launch Alliance Delta II rocket.

Цитировать3:10 a.m. PDT (1010 UTC)

Hands-on work to prepare pad systems, put the infrastructure into the proper configuration and arm the vehicle has been completed, leading to a pad-clear status for all personnel at this time

ЦитироватьThe final Delta II rocket ready to launch ICESat-2

SciNews (https://www.youtube.com/channel/UCjU6ZwoTQtKWfz1urL7XcbA)

Опубликовано: 15 сент. 2018 г.

United Launch Alliance's final Delta II rocket will launch the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) for NASA from Space Launch Complex-2, Vandenberg Air Force Base, California, on 15 September 2018, at 12:46 UTC (05:46 PDT).

Credits: NASA/Bill Ingalls/ULA/USAF 30th Space Wing/Daniel Herrera/Mark Mackley/Alex Valdez/Tony Vauclin/Rodney Speed

Цитировать3:26 a.m. PDT (1026 UTC)

Procedures are underway to turn on RIFCA, the Delta II rocket's Redundant Inertial Flight Control Assembly computer, that will guide the vehicle to its intended destination in space today.

Цитировать3:27 a.m. PDT (1027 UTC)

With the launch pad clear of all personnel, hazardous operations are commencing for today's launch. The helium bottles and nitrogen tanks on the first and second stages are being brought to high-pressure levels, and the second stage fuel and oxidizer tanks, which were loaded earlier this week with storable hypergolic propellants, are being pressurized for flight.

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 19 сек. назад (https://twitter.com/ulalaunch/status/1040914977593466880)

The latest weather forecast shows a 100% chance of favorable weather for the #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) launch at 5:46amPDT. Thanks @30thSpaceWing (https://twitter.com/30thSpaceWing)!

Цитировать3:44 a.m. PDT (1044 UTC) -- RP-1 fueling begins

About 10,000 gallons of the kerosene propellant, called RP-1, are pumping into the base of the rocket from a ground storage tank as the fueling of Delta II's first stage begins for today's launch.

Цитировать(https://img.novosti-kosmonavtiki.ru/185344.jpg)NASA_LSP‏Подлинная учетная запись @NASA_LSP (https://twitter.com/NASA_LSP) 4 мин. назад (https://twitter.com/NASA_LSP/status/1040918403148591109)

Currently, liquid oxygen (LO2) is being loaded onto the #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) vehicle. #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)

Цитировать(https://img.novosti-kosmonavtiki.ru/185344.jpg)NASA_LSP‏Подлинная учетная запись @NASA_LSP (https://twitter.com/NASA_LSP) 6 мин. назад (https://twitter.com/NASA_LSP/status/1040918913222144000)

The #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) 7420-10 configuration was chosen as the perfect match for #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash). This means that it is one of the 7000-series Deltas, it has 4 solid rocket boosters (SRBs), the 2nd stage is powered by an AJ10 engine, and the payload fairing holding #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) is 10ft in diameter.

Цитировать4:01 a.m. PDT (1104 UTC)

T-minus 1 hour, 15 minutes (L-1 hour, 45 minutes) and holding. The count has entered a 15-minute hold to give the team time to finish with tasks prior to liquid oxygen loading. These 15 minutes will be borrowed from the T-minus 15 minute planned hold, which will be shortened from 20 minutes to 5 minutes in duration.

Цитировать4:04 a.m. PDT (1104 UTC) – RP-1 loading is complete

The first stage fuel tank of the Delta II rocket has been fully loaded for today's launch. The tank was filled with a highly refined kerosene during a 20-minute, 23-second process.

Цитировать4:16 a.m. PDT (1116 UTC) -- GO for LOX loading

A successful readiness poll of the launch team by ULA Launch Conductor Scott Barney, with final approval by Launch Director Tom Heter, has given clearance to proceed with liquid oxygen loading into the Delta II rocket's first stage.

Цитировать4:19 a.m. PDT (1119 UTC)

Confirmation has been received that the rocket's guidance and control system has been powered and brought online.

Цитировать4:21 a.m. PDT (1121 UTC) -- LOX loading begins

This is Delta Launch Control at T-minus 1 hour, 10 minutes (L-1 hour, 25 minutes) and counting. Flow valves have opened and liquid oxygen is streaming into the base of the Delta II rocket at Vandenberg Air Force Base's Space Launch Complex-2.

Цитировать4:25 a.m. PDT (1125 UTC) – Launch window update

With LOX load now underway, today's usable launch window has narrowed from two hours, 34 minutes to a total duration of 69 minutes, extending from 5:46 to 6:55 a.m. PDT (8:46-9:55 a.m. EDT; 1246-1355 UTC).

This narrowing ensures that the kerosene fuel on the first stage remains at an optimal temperature and does not become too cold from the cryogenic liquid oxygen during a prolonged launch window.

The kerosene and LOX are consumed by the Aerojet Rocketdyne RS-27A main eying during the initial four-and-a-half minutes of flight to propel the vehicle to the edge of space before staging.

Цитировать09/15/2018 14:46 Stephen Clark

One hour until launch. No problems are being discussed by the ULA launch team at this time. Here are some statistics on today's launch:

[/li]
• 381st Delta rocket launch since 1960
• 237th Delta launch with NASA involvement
• 155th Delta 2 rocket mission since 1989
• 14th Delta 2 to fly in the 7420 configuration
• 241st flight of an RS-27 engine
• 277th flight of an AJ10 engine
• 54th Delta 2 mission overseen by NASA
• 45th Delta 2 rocket launch from Vandenberg Air Force Base
• 3rd launch of the Delta family in 2018
• 7th United Launch Alliance flight this year
• 130th ULA launch overall
• 7th launch from Vandenberg Air Force Base in 2018
  

Цитировать4:48 a.m. PDT (1148 UTC)

Liquid oxygen loading has been accomplished for today's countdown, completing in 26 minutes and 38 seconds. The rocket's tank will be replenished through the remainder of the count to replace the super-cold LOX that warms and naturally boils away.

Цитировать09/15/2018 14:58 Stephen Clark

The liquid oxygen tank on the Delta 2 rocket's first stage is now full. Liquid oxygen will continue flowing into the tank throughout the countdown to replace the super-cold oxidizer as it boils away. The liquid oxygen loading operation in today's countdown took 26 minutes, 38 seconds.

With the completion of liquid oxygen tanking, the Delta 2 rocket now stands fully fueled for launch with the ICESat 2 satellite at 5:46 a.m. PDT (8:46 a.m. EDT; 1246 GMT) from Vandenberg Air Force Base, California. RP-1 fuel was loaded into the first stage earlier in the countdown, and the second stage received its blend of Aerozine 50 and nitrogen tetroxide hypergolic propellants earlier in the launch campaign. The four solid rocket boosters came with their propellants pre-packed.

Цитировать(https://img.novosti-kosmonavtiki.ru/185344.jpg)NASA_LSP‏Подлинная учетная запись @NASA_LSP (https://twitter.com/NASA_LSP) 4 мин. назад (https://twitter.com/NASA_LSP/status/1040934227313913856)

The Electron Losses and Fields Investigation (ELFIN), the Damping and Vibrations Experiment (DAVE), and SurfSat will be doing a variety of space weather and microgravity experiments in orbit.

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 7 мин. назад (https://twitter.com/ulalaunch/status/1040937475991068672)

We have just entered the final planned hold - a 5-minute hold - in the countdown. #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) http://bit.ly/dii_icesat2  (https://t.co/h5G3VkAmnV)

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 11 мин. назад (https://twitter.com/ulalaunch/status/1040943526958297088)

New launch time for #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash): 6:02 a.m. PDT. The shift gives the team additional time to resolve a temperature issue on the second stage.

ЦитироватьICESat-2 launched by the final Delta II rocket

SciNews (https://www.youtube.com/channel/UCjU6ZwoTQtKWfz1urL7XcbA)

Опубликовано: 15 сент. 2018 г.

United Launch Alliance's final Delta II rocket (7420-10C) launched ICESat-2 from Space Launch Complex-2, Vandenberg Air Force Base, California, on 15 September 2018, at 13:02 UTC (06:02 PDT; 09:02 EDT). The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, has a single instrument, the Advanced Topographic Laser Altimeter System, or ATLAS, to measure the elevation of ice sheets, sea ice, forests and more in unprecedented detail. The official designation of the two-stage launch vehicle for the mission is Delta 7420-10C. It had a kerosene and liquid oxygen first stage powered by an Aerojet Rocketdyne RS-27A main engine, four ground-lit, side-mounted Northrop Grumman Graphite Epoxy Motors (GEM-40) solid rocket motors and a hypergolic second stage that burns nitrogen tetroxide and a hydrazine blend called Aerozine 50 in its restartable Aerojet Rocketdyne AJ10-118K engine.

Цитировать09/15/2018 16:57 Stephen Clark

Four CubeSats carried aboard the Delta 2 rocket's second stage will be deployed next, after another restart of the AJ10-118K engine at approximately T+plus 1 hour, 11 minutes.

Meanwhile, deployment of the ICESat 2 satellite's power-generating solar panels is expected shortly.

Цитировать(https://img.novosti-kosmonavtiki.ru/29931.jpg)Tory Bruno‏Подлинная учетная запись @torybruno (https://twitter.com/torybruno) 23 мин. назад (https://twitter.com/torybruno/status/1040966766686560256)

Historic day. Retired the shark, Delta II and the mighty Thor...

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 19 мин. назад (https://twitter.com/ulalaunch/status/1040968115599958016)

ELFIN A CubeSat away!
#DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)


18 мин. назад (https://twitter.com/ulalaunch/status/1040968548393398274)

ELFIN B CubeSay away!
#DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)


16 мин. назад (https://twitter.com/ulalaunch/status/1040969001613045761)

SURFSat and DAVE CubeSats away!
#DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 17 мин. назад (https://twitter.com/ulalaunch/status/1040969576593469443)

"Godspeed #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash)" A final toast from the ULA team to commemorate ULA's final mission.
#ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)

ЦитироватьCountdown Underway for NASA's ICESat-2

NASAKennedy (https://www.youtube.com/channel/UCjJtr2fFcUp6yljzJOzpHUg)

Опубликовано: 15 сент. 2018 г.

The countdown is underway for the liftoff of NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) atop a United Launch Alliance Delta II rocket. Liftoff from Space Launch Complex 2 at Vandenberg Air Force Base in California is scheduled for 5:46 a.m. PDT (8:46 a.m. EDT). ICESat-2 will measure the height of a changing Earth, one laser pulse at a time, 10,000 laser pulses a second. The satellite will carry a single instrument, the Advanced Topographic Laser Altimeter System. ICESat-2 will help scientists investigate why, and how much Earth's frozen and icy areas, called the cryosphere, is changing.

ЦитироватьICESat-2, Delta II Countdown Poll

NASAKennedy (https://www.youtube.com/channel/UCjJtr2fFcUp6yljzJOzpHUg)

Опубликовано: 15 сент. 2018 г.

In the launch control at Vandenberg Air Force Base in California, NASA and contractor managers and engineers monitor progress in the countdown to launch the agency's Ice, Cloud and land Elevation Satellite-2 (ICESat-2). The poll is designed to verify that all is ready for liftoff, now targeted for 6:02 a.m. PDT (9:02 a.m. EDT). The satellite will carry the Advanced Topographic Laser Altimeter System to help scientists better understand why and how much Earth's frozen and icy areas, called the cryosphere, is changing.

ЦитироватьLiftoff of NASA's ICESat-2

NASAKennedy (https://www.youtube.com/channel/UCjJtr2fFcUp6yljzJOzpHUg)

Опубликовано: 15 сент. 2018 г.

A United Launch Alliance Delta II rocket lifts off at 6:02 a.m. PDT (9:02 a.m. EDT) from Space Launch Complex 2 at Vandenberg Air Force Base in California carrying NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2). The spacecraft will measure the height of a changing Earth, one laser pulse at a time, 10,000 laser pulses a second. The satellite will carry a single instrument, the Advanced Topographic Laser Altimeter System. ICESat-2 will help scientists investigate why, and how much Earth's frozen and icy areas, called the cryosphere, is changing.

ЦитироватьNASA's ICESat-2 Separates from Upper Stage

NASAKennedy (https://www.youtube.com/channel/UCjJtr2fFcUp6yljzJOzpHUg)

Опубликовано: 15 сент. 2018 г.

A camera on the upper stage shows NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) as it is deployed into orbit above the Earth. Immediately following separation, agency and industry managers celebrate the successful launch.

Цитировать(https://img.novosti-kosmonavtiki.ru/67516.jpg)Jonathan McDowell‏Подлинная учетная запись @planet4589 (https://twitter.com/planet4589) 32 мин. назад (https://twitter.com/planet4589/status/1040968547353157632)

ELFIN deployed from the Delta at 1418 UTC. A 3U cubesat to study ionospheric electrons, from UCLA


31 мин. назад (https://twitter.com/planet4589/status/1040968742740606977)

ELFIN-B (aka ELFIN-STAR) deployed at 1420 UTC


31 мин. назад (https://twitter.com/planet4589/status/1040969078775734272)

CalPoly's DAVE and UCF's Surface Charging Satellite released at 1421 UTC

ЦитироватьInterview with NASA Launch Director

NASAKennedy (https://www.youtube.com/channel/UCjJtr2fFcUp6yljzJOzpHUg)

Опубликовано: 15 сент. 2018 г.

Following the successful liftoff of a United Launch Alliance Delta II rocket orbiting NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2), Launch Director Tim Dunn speaks with Joshua Santora of NASA Communications and Mic Woltman, a Launch Services Program engineer.

ЦитироватьICESat-2 Spacecraft Healthy after Arriving in Orbit



NASA's ICESat-2 spacecraft deployed its four solar panels and is drawing power, indicating it is healthy upon its arrival in orbit. The spacecraft launched on the final flight of the United Launch Alliance Delta II rocket, lifting off from Space Launch Complex-2 at California's Vandenberg Air Force Base at 6:02 a.m. PDT (9:02 a.m. EDT).
Ground stations in Svalbard, Norway, have acquired signals from the spacecraft. It is performing as expected and orbiting the globe, pole to pole, at 17,069 mph from an average altitude of 290 miles.

Цитировать(https://img.novosti-kosmonavtiki.ru/29931.jpg)Tory Bruno‏Подлинная учетная запись @torybruno (https://twitter.com/torybruno) 6 мин. назад (https://twitter.com/torybruno/status/1040978105299599360)

130

Цитировать(https://img.novosti-kosmonavtiki.ru/185339.jpg)NASA‏Подлинная учетная запись @NASA (https://twitter.com/NASA) 11 мин. назад (https://twitter.com/NASA/status/1040977044098764801)

Lifting off at 9:02am ET Saturday atop a @ULALaunch (https://twitter.com/ulalaunch) #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) rocket, @NASA_ICE (https://twitter.com/NASA_ICE)'s #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) is safely on orbit and ready to embark on its mission to measure the ice of Earth's frozen reaches with unprecedented accuracy. Learn more: https://go.nasa.gov/2MyquF9  (https://t.co/wbdhliMBZK)

(https://img.novosti-kosmonavtiki.ru/170091.jpg)

Цитировать09/15/2018 17:36 Stephen Clark

One more burn by the second stage's AJ10 engine is planned at 7:52 a.m. PDT (10:52 a.m. EDT; 1452 GMT). The braking maneuver will last around 37 seconds, steering the rocket back into Earth's atmosphere for a destructive re-entry over the Pacific Ocean.

Any small debris from the second stage that survives the fiery re-entry will impact in the remote Pacific Ocean at 8:12 a.m. PDT (11:12 a.m. EDT; 1512 GMT).

ЦитироватьUnited Launch Alliance Selects NASA's Kennedy Space Center Visitor Complex as the Future Home of the Last Delta II Rocket

Centennial, Colo., Sept. 15, 2018 – United Launch Alliance (ULA) announced today that the last Delta II rocket will join a lineup of historic rockets in the Rocket Garden on display at NASA's Kennedy Space Center Visitor Complex in Cape Canaveral, Florida. 

"The Delta II rocket has been a venerable workhorse for NASA and civilian scientists, the U.S. military, and commercial clients throughout its almost 30 years of service," said Tory Bruno, ULA president and CEO. "This program comes to a close with the final launch of NASA's ICESat-2, but its legacy will continue and the Visitor Complex will help us keep the story of the success of this much-revered rocket in the hearts and minds of the public."

Спойлер

The maiden Delta II took flight on Valentine's Day in 1989, successfully delivering the first operational GPS satellite into space. Since that first launch, Delta II rockets have launched 154 successful missions. Its resume includes several trips to Mars as well as the planet-hunting Kepler, the twin lunar-orbiting GRAIL spacecraft, 48 GPS satellites and numerous commercial imaging and communications satellites.

With more than a century of combined heritage, United Launch Alliance is the nation's most experienced and reliable launch service provider. ULA has successfully delivered more than 125 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

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Цитировать09/15/2018 18:36 Stephen Clark

NASA has confirmed the power-generating solar array on the ICESat 2 satellite has fully deployed to begin charging the spacecraft's batteries. This is a major step in the satellite's post-launch activation and commissioning phase.

Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 34 мин. (https://twitter.com/ulalaunch/status/1040987450800332801)

Check out this and other amazing photos of today's #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) mission in our Flickr album

https://flic.kr/s/aHsmm8NzF7  (https://t.co/UvEts3YrsI)

(https://img.novosti-kosmonavtiki.ru/170102.jpg)

ЦитироватьAdvanced technologies from Northrop Grumman support launch of ULA's Delta II rocket and deployment of NASA's satellite

September 15, 2018

DULLES, Va. – Sept. 15, 2018 – Northrop Grumman Corporation (NYSE: NOC) today announced the Ice, Cloud and Land Elevation spacecraft (ICESat-2), built by the company for NASA, successfully launched aboard a United Launch Alliance (ULA) Delta II rocket from Vandenberg Air Force Base, California. In addition to manufacturing the spacecraft, Northrop Grumman also provided propulsion, key composite structures, a space navigation system and other components on the Delta II launch vehicle. This event marks the final launch of the Delta II rocket.

Спойлер

(https://img.novosti-kosmonavtiki.ru/190727.jpg)
NASA's ICESat-2 satellite built by Northrop Grumman successfully launched September 15, 2018, from Vandenberg Air Force Base in California.

ICESat-2 will provide precise measurements of the changing height of Earth's glaciers, ice sheets and sea ice. The satellite is carrying the Advanced Topographic Laser Altimeter System (ATLAS), built at NASA's Goddard Space Flight Center, which will measure the height of a changing Earth one laser pulse at a time. The instrument will enable scientists to measure the topography of the Greenland and Antarctic ice sheets in unprecedented detail. With 10,000 laser pulses per second, the fast-shooting laser technology allows ATLAS to take measurements every 28 inches along the satellite's path.

"ICESat-2 demonstrates the company's expertise in delivering high-quality Earth science satellites that help scientists gain a better understanding of the changes that can affect the planet's frozen and icy areas," said Steve Krein, vice president, science, environmental and weather programs, Northrop Grumman. "As a key focus of NASA's Earth science research, ICESat-2 paves the way for scientific discoveries that will yield new data on the potential effects of a changing Earth."

Northrop Grumman designed and manufactured the ICESat-2 spacecraft at its Gilbert, Arizona, satellite manufacturing facility and will provide mission operations at its Dulles, Virginia, site. The company built the satellite on its flight-proven LEOStar-3™ platform, which will be also used for the upcoming Landsat-9 and JPSS spacecraft. Company facilities in California and Maryland provided numerous subsystems, including the satellite's diaphragm propellant tank, pressurant tank, solar arrays and heat pipes for two components on the spacecraft. Northrop Grumman also supplied its Scalable Space Inertial Reference Unit (Scalable SIRU™) navigation system for the satellite to enable spacecraft attitude control and sensor pointing/stabilization. The Scalable SIRU is the industry standard for high-precision, long-life attitude control solutions supporting commercial, government and civil space missions.

Northrop Grumman also manufactured the Delta II rocket's four Graphite Epoxy Motors 40 (GEM 40), which provided an additional 460,000 pounds of maximum thrust during today's launch. Northrop Grumman has been supplying solid propulsion motors to ULA and its predecessor companies for a variety of launch vehicles since 1964 and is ULA's largest legacy supplier of solid propulsion.

"As the Delta II program finishes its long, successful run, we note that 1,003 GEM 40 strap-on boosters have helped launch 132 Delta II missions, including today's," said Charlie Precourt, vice president and general manager, propulsion systems, Northrop Grumman. "The Delta II rocket enjoys the longest consecutive success record in commercial rocket motor history."

Northrop Grumman manufactured the GEM 40 motors in Utah, the Delta II rocket's 10-foot diameter composite fairing in Mississippi and the rocket's second stage helium and nitrogen pressurization bottles in California.

Northrop Grumman is a leading global security company providing innovative systems, products and solutions in autonomous systems, cyber, C4ISR, space, strike, and logistics and modernization to customers worldwide. Please visit news.northropgrumman.com (http://news.northropgrumman.com/) and follow us on Twitter, @NGCNews (http://www.twitter.com/ngcnews), for more information.

[свернуть]

ЦитироватьSept. 15, 2018
RELEASE 18-078

NASA, ULA Launch Mission to Track Earth's Changing Ice

NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2 (https://www.nasa.gov/content/goddard/icesat-2)) successfully launched fr om California at 9:02 a.m. EDT Saturday, embarking on its mission to measure the ice of Earth's frozen reaches with unprecedented accuracy.

ICESat-2 lifted off from Space Launch Complex-2 at Vandenberg Air Force Base on United Launch Alliance's final Delta II rocket. Ground stations in Svalbard, Norway, acquired signals from the spacecraft about 75 minutes after launch. It's performing as expected and orbiting the globe, from pole to pole, at 17,069 mph from an average altitude of 290 miles.

Спойлер

(https://img.novosti-kosmonavtiki.ru/207772.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat2.jpg)
The United Launch Alliance (ULA) Delta II rocket with the NASA Ice, Cloud and land Elevation Satellite-2 (ICESat-2) onboard is seen shortly after the mobile service tower at SLC-2 was rolled back, Saturday, Sept. 15, 2018, at Vandenberg Air Force Base in California. The ICESat-2 mission will measure the changing height of Earth's ice.
Credits: NASA/ Bill Ingalls

"With this mission we continue humankind's exploration of the remote polar regions of our planet and advance our understanding of how ongoing changes of Earth's ice cover at the poles and elsewh ere will affect lives around the world, now and in the future," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate.

ICESat-2 carries a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS (https://icesat.gsfc.nasa.gov/icesat2/instrument.php)). ATLAS will be activated approximately two weeks after the mission operations team completes initial testing of the spacecraft. Then ICESat-2 will begin work on its science objective, gathering enough data to estimate the annual height change of the Greenland and Antarctic ice sheets to within four millimeters – the width of a pencil.

"While the launch today was incredibly exciting, for us scientists the most anticipated part of the mission starts when we switch on the laser and get our first data," said Thorsten Markus, ICESat-2 project scientist at NASA's Goddard Space Flight Center. "We are really looking forward to making those data available to the science community as quickly as possible so we can begin to explore what ICESat-2 can tell us about our complex home planet."

The high-resolution data will document changes in the Earth's polar ice caps, improve forecasts of sea level rise bolstered by ice sheet melt in Greenland and Antarctica, and help scientists understand the mechanisms that are decreasing floating ice and assess how that sea ice loss affects the ocean and atmosphere.

ICESat-2 continues the record of ice height measurements started by NASA's original ICESat mission, which operated from 2003 to 2009, that were continued by the agency's annual Operation IceBridge airborne flights over the Arctic and Antarctic, which began in 2009. Data from ICESat-2 will be available to the public through the National Snow and Ice Data Center (https://nsidc.org/).

Goddard built and tested the ATLAS instrument, and manages the ICESat-2 mission for NASA's Science Mission Directorate. Northrop Grumman designed and built the spacecraft bus, installed the instrument and tested the completed satellite. NASA's Launch Services Program, based at Kennedy Space Center in Florida, is responsible for launch service acquisition, integration, analysis and launch management.

[свернуть]

Last Updated: Sept. 15, 2018
Editor: Katherine Brown

Цитировать(https://pbs.twimg.com/profile_images/981105707402477570/ClqZBljg_bigger.jpg)Jack Beyer‏ @thejackbeyer (https://twitter.com/thejackbeyer) 10 мин. назад (https://twitter.com/thejackbeyer/status/1040998497527390209)

The last #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) lifting #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) into orbit. Shot from a 4300' mountain top in California.
@ulalaunch (https://twitter.com/ulalaunch) @torybruno (https://twitter.com/torybruno) @NASA (https://twitter.com/NASA) @NASASpaceflight (https://twitter.com/NASASpaceflight)

(https://img.novosti-kosmonavtiki.ru/170088.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/31566.jpg)Brady Kenniston‏ @TheFavoritist (https://twitter.com/TheFavoritist) 1 ч. назад (https://twitter.com/TheFavoritist/status/1040984517069041664)

Liftoff of the final @ULAlaunch (https://twitter.com/ulalaunch) Delta II flying NASA's #IceSat2 (https://twitter.com/hashtag/IceSat2?src=hash) into a polar orbit! This rocket is incredibly photogenic! Check out the full launch gallery later on http://NASAspaceflight.com/l2  (https://t.co/bmjXsHet2J)

(https://img.novosti-kosmonavtiki.ru/170100.jpg)

Спойлер

(https://img.novosti-kosmonavtiki.ru/170098.jpg)(https://img.novosti-kosmonavtiki.ru/170099.jpg)

[свернуть]

ЦитироватьUnited Launch Alliance Successfully Launches Final Delta II Rocket with NASA's ICESat-2

Delta II ICESat-2 Launch Information Page (https://www.ulalaunch.com/missions/delta-ii-icesat-2)
Delta II ICESat-2 Mission Booklet (https://www.ulalaunch.com/docs/default-source/launch-booklets/MOB_ICESat2.pdf)
Photos: Delta II ICESat-2  (https://flic.kr/s/aHsmm8NzF7)

The end of an era for the industry workhorse

Vandenberg Air Force Base, Calif., (Sept. 15, 2018) – A United Launch Alliance (ULA) Delta II rocket carrying NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) spacecraft lifted off from Space Launch Complex-2 on Sept. 15 at 6:02 a.m. PDT. This marks the final mission of the Delta II rocket, which first launched on Feb. 14, 1989, and launched 155 times including ICESat-2.

From its origin as the launch vehicle for the first Global Positioning System (GPS) satellites to NASA's Earth observing, science and interplanetary satellites – including Mars rovers Spirit and Opportunity – to vital commercial communication and imaging satellites, the Delta II rocket has truly earned its place in space history.

"ULA is proud that the Delta II rocket has been a significant piece of history, launching more than 50 missions for NASA," said Gary Wentz, ULA vice president of Government and Commercial Programs. "I sincerely thank the entire ULA team, NASA, U.S. Air Force, and all of our partners and suppliers who have worked diligently to launch the final Delta II rocket, as well as the dedication of the teams throughout the past 29 years of the program."

Спойлер

ICESat-2 will provide scientists with height measurements to create a global portrait of Earth's third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, forests and more. Northrop Grumman built the spacecraft. In addition to ICESat-2, this mission included four CubeSats which launched from dispensers mounted to the Delta II second stage.

This mission launched aboard a Delta II 7420-10 configuration rocket, which included a 10-foot-diameter payload fairing (PLF). The booster for this mission was powered by the RS-27A engine and the second stage was powered by the AJ10-118K engine.

This is ULA's seventh launch in 2018 and the 130th successful launch since the company was formed in December 2006.

ULA's next launch is the AEHF-4 mission for the U.S. Air Force on an Atlas V rocket from Space Launch Complex-41 at Cape Canaveral Air Force Station, Florida.

With more than a century of combined heritage, United Launch Alliance is the nation's most experienced and reliable launch service provider. ULA has successfully delivered 130 satellites to orbit that aid meteorologists in tracking severe weather, unlock the mysteries of our solar system, provide critical capabilities for troops in the field and enable personal device-based GPS navigation.

[свернуть]

Цитировать(https://img.novosti-kosmonavtiki.ru/186305.jpg)Tactical Sky Guy‏ @tacticalskyguy (https://twitter.com/tacticalskyguy) 2 ч. назад (https://twitter.com/tacticalskyguy/status/1040980817923592194)

В ответ @SpaceflightNow (https://twitter.com/SpaceflightNow)

@ulalaunch (https://twitter.com/ulalaunch) @Erdayastronaut (https://twitter.com/Erdayastronaut) @DJSnM (https://twitter.com/DJSnM) @earthskyscience (https://twitter.com/earthskyscience) @SpaceflightIns (https://twitter.com/SpaceflightIns) @Marine_layer (https://twitter.com/Marine_layer)

(https://img.novosti-kosmonavtiki.ru/170094.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/186134.jpg)Glenn Beltz‏ @gb0n (https://twitter.com/gb0n) 2 ч. назад (https://twitter.com/gb0n/status/1040981417939787776)

Another view of the #IceSat2 (https://twitter.com/hashtag/IceSat2?src=hash) launch from Goleta, showing the exhaust plume nicely illuminated by the about-to-rise Sun.

(https://img.novosti-kosmonavtiki.ru/170095.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/186319.jpg)Pauline Acalin‏ @w00ki33 (https://twitter.com/w00ki33) 4 ч. назад (https://twitter.com/w00ki33/status/1040946993407832064)

At the press site awaiting launch of NASA's ICESat-2. Crisp and clear view of the Delta II. #nasa (https://twitter.com/hashtag/nasa?src=hash) #IceSat2 (https://twitter.com/hashtag/IceSat2?src=hash)

(https://img.novosti-kosmonavtiki.ru/170076.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/186406.jpg)John Kraus‏ @johnkrausphotos (https://twitter.com/johnkrausphotos) 1 ч. назад (https://twitter.com/johnkrausphotos/status/1040989679057657856)

Ignition! United Launch Alliance's #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) rocket begins its final journey to space, delivering the #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) satellite to orbit.

(https://img.novosti-kosmonavtiki.ru/170104.jpg)

ЦитироватьVandenberg launches Delta II ICESat-2
30th Space Wing Public Affairs / Published September 15, 2018

(https://img.novosti-kosmonavtiki.ru/143369.webp) (https://media.defense.gov/2018/Sep/15/2001966668/-1/-1/0/180915-F-XJ735-023.JPG)

VANDENBERG AIR FORCE BASE, Calif. -- Team Vandenberg successfully launched a Delta II rocket carrying NASAs ICESat-2 payload from Space Launch Complex-2 here, Saturday, September 15, at 6:02 a.m. PDT.

Цитировать(https://img.novosti-kosmonavtiki.ru/186406.jpg)John Kraus‏ @johnkrausphotos (https://twitter.com/johnkrausphotos) 2 ч. назад (https://twitter.com/johnkrausphotos/status/1040983602933096449)

#DeltaII (https://twitter.com/hashtag/DeltaII?src=hash)'s GEM-40 solid rocket motors and RS-27A engine put on a breathtaking display of ferocity during the launch of #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) this morning — What an amazing sendoff for the incredible United Launch Alliance vehicle!

(https://img.novosti-kosmonavtiki.ru/170097.jpg)

ЦитироватьICESat-2 Successfully Launched on Final Flight of Delta II Rocket

Anna Heiney (https://blogs.nasa.gov/kennedy/author/aheiney/)
Posted Sep 15, 2018 at 12:17 pm

(https://img.novosti-kosmonavtiki.ru/130830.jpg) (https://img.novosti-kosmonavtiki.ru/130830.jpg)
The final United Launch Alliance Delta II rocket lifts off fr om Space Launch Complex 2 at Vandenberg Air Force Base in California, on Sept. 15, 2018, carrying NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2). Liftoff was at 9:02 a.m. EDT (6:02 a.m. PDT). Photo credit: NASA/Kim Shiflett

NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2 (https://www.nasa.gov/icesat2)) is embarking on a three-year mission to measure the ice of Earth's frozen and icy areas after a successful liftoff today at 6:02 a.m. PDT (9:02 a.m. EDT) from Space Launch Complex-2 at Vandenberg Air Force Base in California. The spacecraft was delivered to Earth orbit by the United Launch Alliance Delta II rocket, which completed its final launch after 29 years in service.

Спойлер

"With this mission we continue humankind's exploration of the remote polar regions of our planet and advance our understanding of how ongoing changes of Earth's ice cover at the poles and elsewh ere will affect lives around the world, now and in the future," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate.

Using its only onboard instrument, the Advanced Topographic Laser Altimeter System (ATLAS (https://icesat.gsfc.nasa.gov/icesat2/instrument.php)), ICESat-2 will gather enough data to estimate the annual height change of the Greenland and Antarctic ice sheets to within four millimeters — the width of a pencil.

The high-resolution data will document changes in the Earth's polar ice caps and improve forecasts of sea level rise bolstered by ice sheet melt in Greenland and Antarctica. It also will help scientists understand the mechanisms that are decreasing floating ice and assess how that sea ice loss affects the ocean and atmosphere.

(https://img.novosti-kosmonavtiki.ru/130827.jpg) (https://blogs.nasa.gov/icesat2/wp-content/uploads/sites/283/2018/09/DeltaII_ICESat2_2.jpg)
Signs at Vandenberg Air Force Base's Space Launch Complex-2 bear dedications to all the employees, suppliers, customers and Air Force Range personnel who designed, built and launched the Delta II between 1989 and today, as well as ICESat-2 professionals and family members no longer with us, whose contributions live on. Photo courtesy of United Launch Alliance

ICESat-2 builds upon the record of ice height measurements started by NASA's original ICESat mission, which operated from 2003 to 2009. These measurements were continued by the agency's annual Operation IceBridge airborne flights over the Arctic and Antarctic, which began in 2009. Data from ICESat-2 will be available to the public through the National Snow and Ice Data Center (https://nsidc.org/).

The first ICESat mission launched in January 2003, also on a Delta II from Vandenberg.

"I'm thrilled that we were able to close the chapter on Delta II with a huge success for an incredibly important science payload," said NASA Launch Manager Tim Dunn.

"ICESat-2 is going to do cutting-edge scientific data gathering; the precision measurements it's going to make from space are going to be incredible. So to be able to say we launched this very important science mission on the final flight of the industry workhorse is just a huge accomplishment for the entire team," he added.

A host of small satellites, known as CubeSats, also were carried into space aboard the Delta II. The Educational Launch of Nanosatellites (ELaNa (https://www.nasa.gov/mission_pages/smallsats/elana/index.html)) XVIII payload included University of Central Florida's  SurfSat; California Polytechnic State University's DAVE (Damping and Vibration Experiment); and UCLA's ELFIN (Electron Losses and Fields Investigation (ELFIN) and ELFIN-STAR (Spatio-Temporal Ambiguity Resolution). The CubeSats, which flew inside Poly Picosatellite Orbital Deployers (P-PODs) mounted to the rocket's second stage, were successfully deployed on time, more than an hour after liftoff.

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Цитировать(https://img.novosti-kosmonavtiki.ru/67516.jpg)Jonathan McDowell‏Подлинная учетная запись @planet4589 (https://twitter.com/planet4589) 29 мин. назад (https://twitter.com/planet4589/status/1041035411982835712)

ICESAT launch: five objects cataloged as expected, in 455 x 469 km x 93.0 deg orbits. Presumably ICESAT and 4 cubesats; Delta stage not cataloged despite completing a full orbit before deorbiting.

ЦитироватьDelta II ICESat-2 Launch Highlights

United Launch Alliance (https://www.youtube.com/channel/UCnrGPRKAg1PgvuSHrRIl3jg)

Опубликовано: 15 сент. 2018 г.

A United Launch Alliance (ULA) Delta II rocket carrying launch NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) mission lifts off from Space Launch Complex-2 at Vandenberg Air Force Base, California, on Sept. 15, 2018. ICESat-2 is the 155th and final launch of the Delta II rocket. From its origin as the launch vehicle for the first Global Positioning System (GPS) satellites to NASA's Earth observing, science and interplanetary satellites including Mars rovers Spirit and Opportunity to vital commercial communication and imaging satellites, the Delta II rocket has truly earned its place in space history.

ЦитироватьСтарый пишет:
Прощай, Дельта-2!

ЦитироватьАлександр Хороших пишет:

ЦитироватьСтарый пишет:
Прощай, Дельта-2!

И мотор, разработанный в середине 50-х.

ЦитироватьСтарый пишет:
Мотор на ней от Сатурна-1.

ЦитироватьСтарый пишет:
Вторая ступень - AJ-10 - тоже неслабый музейный экспонат. Надо же, до наших дней пролетала ракета с вытеснительной подачей на второй ступени.

ЦитироватьСтарый пишет:
Флакон-9 будет достойным наследником славных традиций Дельты и Титана.

ЦитироватьАлександр Хороших пишет:

ЦитироватьСтарый пишет:
Флакон-9 будет достойным наследником славных традиций Дельты и Титана.

Флакон попытался обзавестись бустерами, как Титан-3. Но пока как-то неуверенно и даже неохотно.

ЦитироватьСтарый пишет:
Флакон это прежде всего "открытая схема и без водорода" то есть продолжение идеологии Дельты и Титана.

ЦитироватьАлександр Хороших пишет: 
На "Атласе" и "Титане" на верхних ступенях часто ставили "Центавр"  :oops:

ЦитироватьСтарый пишет:
Атлас-Центавр без Центавра не летал

ЦитироватьСтарый пишет:
А на Титане Центавр ставился факультативно.

ЦитироватьАлександр Хороших пишет:

ЦитироватьСтарый пишет:
Атлас-Центавр без Центавра не летал

Были же вроде модификации без него?.. С "Адженой"?.. Или я чего путаю?

ЦитироватьАлександр Хороших пишет:
Как в анекдоте: "И всё же".  :)
ИМХО, тенденция заметная: отказ в США от двигунов открытой схемы. Мерлин у Маска, БЕ-4 у Безоса, АР-1 у Рокитдайна. Именно в них в США увидели перспективу  :)

ЦитироватьСтарый пишет:
Атлас-Аджена это не Атлас-Центавр.  :)

ЦитироватьСтарый пишет:
Я бы не был столь смел чтобы обозвать Мерлины двигателями НЕ открытой схемы.  :)

ЦитироватьСтарый пишет:
Мерлины это и есть второе пришествие открытой схемы. В которых США и увидели перспективу.

ЦитироватьАлександр Хороших пишет:

ЦитироватьСтарый пишет:
Мерлины это и есть второе пришествие открытой схемы. В которых США и увидели перспективу.

А я вот "щитаю", что наоборот. США повернулись в сторону замкнутой схемы. И Китай туда же.  :)

ЦитироватьАлександр Хороших пишет:
И Китай туда же.

ЦитироватьСтарый пишет:
Это где и когда ж США повернулись в сторону замкнутой схемы? Когда отдались Маску или раньше?  ;)

ЦитироватьСтарый пишет:
С Китаем та же история что и с США - за еду прикупил у хохлов наш движок.

Цитировать(https://img.novosti-kosmonavtiki.ru/67516.jpg)Jonathan McDowell‏Подлинная учетная запись @planet4589 (https://twitter.com/planet4589) 58 мин. назад (https://twitter.com/planet4589/status/1041203215382061056)

First two TLE sets for ICESAT-2 have a different inclination and probably refer to the post-SECO-3 Delta second stage, not to ICESAT. Later TLE sets have the correct 92.0 deg inclination

ЦитироватьEarly morning launch closes book on Delta 2 legacy spanning nearly 30 years
September 15, 2018 (https://spaceflightnow.com/2018/09/) | Stephen Clark (https://spaceflightnow.com/author/stephen-clark/)

(https://img.novosti-kosmonavtiki.ru/144971.jpg)
A United Launch Alliance Delta 2 rocket lifted off at 6:02 a.m. PDT (9:02 a.m. EDT; 1302 GMT) Saturday fr om Vandenberg Air Force Base, California. Credit: Alex Polimeni/Spaceflight Now

A United Launch Alliance Delta 2 rocket fired away from a California military base and disappeared into an overcast cloud deck Saturday on its final flight, carrying a NASA research satellite into orbit and closing the book on a nearly 30-year legacy of launches.

The 128-foot-tall (39-meter) rocket lit its kerosene-fueled Aerojet Rocketdyne RS-27A main engine at 6:02 a.m. PDT (9:02 a.m. EDT; 1302 GMT), then ignited four Northrop Grumman-built strap-on solid rocket boosters a few seconds later to propel the Delta 2 off its launch pedestal at Vandenberg Air Force Base, California.

Riding roughly 650,000 pounds of thrust, the Delta 2 rocket — emblazoned in its iconic bluish-green paint scheme — disappeared into low clouds, but long-range infrared tracking cameras followed the launcher's progress as it pitched to the south from Vandenberg, a military-run spaceport on California's Central Coast northwest of Los Angeles.

The four solid rocket boosters burned out and jettisoned to fall into the Pacific Ocean less than 90 seconds after liftoff, and the first stage's RS-27A main engine — tracing its design heritage to NASA's Saturn 1 and 1B rocket programs of the 1960s — shut down for the final time at T+plus 4 minutes, 24 seconds.

After releasing the first stage, the Delta 2's second stage Aerojet Rocketdyne AJ10-118K engine fired for the first of four burns on Saturday's mission, then shut down at around the 11-minue point of the flight. The Delta 2 coasted over Antarctica, then headed north over the Indian Ocean before reigniting the upper stage engine for less than 7 seconds to circularize its orbit.

NASA's ICESat 2 satellite, kicking off a $1 billion mission using lasers to measure global ice sheet changes from space, deployed from the rocket's upper stage around 53 minutes after liftoff. A live video view beamed down from the Delta 2 showed the 3,340-pound (1,515-kilogram) NASA research craft flying away from the rocket against the inky black backdrop of space.

ULA programmed the rocket to release ICESat 2 in an orbit nearly 300 miles, or about 474 kilometers, above Earth. Delta 2 flight commentator Patrick Moore confirmed the rocket achieved an orbit very close to pre-flight predictions.

ICESat 2, built by Northrop Grumman Innovation Systems, unfurled its solar panel shortly after separating from the Delta 2, commencing a 60-day commissioning schedule before starting regular scientific observations of land and sea ice in November.

Спойлер

(https://img.novosti-kosmonavtiki.ru/144944.jpg)
The Delta 2 rocket climbs away from Space Launch Complex 2-West at Vandenberg Air Foce Base, California. Credit: NASA/Bill Ingalls

Another burn by the Delta 2's AJ10 second stage engine slightly adjusted its orbit to set up for the separation of four CubeSats developed by university students. The CubeSats launched on Saturday's mission were:

[/li]
• ELFIN, or the Electron Losses and Fields Investigation, a space weather mission developed at UCLA using three scientific instruments in a 3U+ CubeSat form factor.
• ELFIN-STAR, also from UCLA,, an identical 3U+ CubeSat that will allow scientists to more precisely measure the radiation environment in low Earth orbit.
• DAVE, or the Damping and Vibrations Experiment,, a 1U CubeSat developed at Cal Poly with a payload to evaluate a mechanical damping technology in microgravity.
• SurfSat, a 2U CubeSat developed at the University of Central Florida to measure static charging on spacecraft surfaces in orbit.
  

Meanwhile, the Delta 2 upper stage fired once more for a braking burn to drop out of orbit and re-enter Earth's atmosphere over the Pacific Ocean, wh ere the rocket was expected to break apart and burn up. The deorbit burn was intended to ensure the mission does not add more space junk to orbital traffic lanes, and the re-entry marked the formal conclusion of the final Delta 2 flight.

"I'm a little bit sad," said Tim Dunn, NASA's launch director for the ICESat 2 mission. "I'm thrilled with mission success, and that we were able to close the chapter on Delta with a huge success of an incredibly important science payload.

"ICESat 2 is going to do cutting edge scientific data-gathering, the precision measurements it's going to do from space are just going to be incredible," said Dunn, a 22-year veteran of the Delta 2 rocket program at Boeing and NASA. "So to be able to say that we launched this very important science mission on the final flight of the industry workhorse is just a huge accomplishment for the entire team. I have a lot of personal feelings about the Delta 2, but I'm really just a very small part of the entire Delta 2 team."

While ULA's Delta 4 rocket will remain in service for several more years, the Delta 2 rocket was the last U.S. launcher flying that could trace its basic design to the dawn of the Space Age.

(https://img.novosti-kosmonavtiki.ru/144918.jpg)
The Delta 2 rocket launched Saturday featured four strap-on solid rocket boosters. Credit: United Launch Alliance

...

Here are some statistics on Saturday's launch:

[/li]
• 381st Delta rocket launch since 1960
• 724th launch of a Thor-based rocket
• 237th Delta launch with NASA involvement
• 155th Delta 2 rocket mission since 1989
• 14th Delta 2 to fly in the 7420 configuration
• 241st flight of an RS-27 engine
• 277th flight of an AJ10 engine
• 1,000th-1,003rd GEM-40 solid rocket motors launched on Delta 2s
• 54th Delta 2 mission overseen by NASA
• 45th Delta 2 rocket launch from Vandenberg Air Force Base
  

"The Delta 2 vehicle has touched the life of probably every single person in America in the technoloy that it's enabled over its 30 years," Messer said. "It's been a very, very prominent part of space history."

Other Delta 2s dispatched NASA's first three Mars rovers — Sojourner, Spirit and Opportunity — toward the red planet, along with the MESSENGER mission to orbit Mercury, the Dawn mission to the asteroid belt, the Spitzer Space Telescope, the planet-hunting Kepler observatory, weather satellites, and dozens of commercial and military communications spacecraft.

From Vandenberg, Delta 2 rockets hauled the bulk of Iridium's first-generation fleet of voice and data relay satellites into low Earth orbit on 12 launches from 1997 through 2002. Those satellites are now being replaced by an upgraded Iridium fleet launching on SpaceX Falcon 9 rockets.

The Globalstar satellite network, also designed for mobile communications, was deployed by a series of Delta 2 rockets launched from Cape Canaveral.

Saturday's launch extended the Delta 2's record to 100 successful launches in a row, a streak dating back to Jan. 17, 1997, when the workhorse suffered one of the most memorable rocket failures of the last quarter-century. A Delta 2 exploded just 13 seconds after a launch from Cape Canaveral with a GPS satellite, raining debris back down on its launch pad, leaving a cratered parking lot and destroyed cars outside the pad bunker.

No one was injured in the accident, and the Delta 2 returned to flight less than four months later with an Iridium satellite launch from California.

"The Delta 2 will go down in history as one of the world's most successful launch vehicles, and we're proud to be part of that legacy," said Eileen Drake, CEO and president of Aerojet Rocketdyne, supplier of the Delta 2's first and second stage engines.

The RS-27A main engine, which generates 200,000 pounds of thrust at sea level, is a descendant of the H-1 engine used on the main stages of NASA's Saturn 1 and Saturn 1B rockets, the predecessors of the Saturn 5 moon rocket in the Apollo program. In addition to a main thrust chamber, the RS-27A has two vernier engines for roll control during flight.

The second stage's AJ-118K engine has its roots in the ballistic missile programs of the 1950s, and was later updated to power the Transtage, an upper stage that flew on Titan rockets, according to Aerojet Rocketdyne. It burns a combination of Aerozine 50, a fuel cocktail made by mixing hydrazine and unsymmetrical dimethyl-hydrazine, and nitrogen tetroxide oxidizer to provide 9,850 pounds of thrust at altitude.

Elizabeth Jones, Aerojet Rocketdyne's RS-27 and AJ10 program manager, said Friday that the Delta 2's engines went through several upgrades over the decades, adding thrust and performance as the rocket's size crew larger. Both types of engines will not fly again after Saturday's mission, but a similar engine to the AJ10 will continue launching with NASA's Orion crew capsule.

"We've been saying at some of our meetings, who's going be the first one to crack? Is anybody going to tear up? It's an emotional time, there's a long legacy to be proud of," Jones said.

"I'll miss the work, I'll miss the people," said Latanjia Robinson, Aerojet Rocketdyne's AJ10 chief engineer. "I'll miss traveling to the launch sites to support the various tasks prior to launch, and the launches themselves.

"But it'll be rewarding. I look forward to a successful mission," Robinson said in an interview before Saturday's launch.

The Delta 2 could fly with three, four or nine solid rocket motors built by Northrop Grumman Innovation Systems, formerly known as Orbital ATK. Over the history of the program, more than 1,000 of the solid motors have launched with Delta 2 rockets.

Other holdover practices from the early Space Age that continued with the Delta 2 included a manual command from the control center to start the RS-27A main engine. Delta 2 countdowns didn't use an auto sequencer like newer rockets.

(https://img.novosti-kosmonavtiki.ru/144943.jpg)
The ICESat 2 satellite was encapsulated inside the Delta 2's clamshell-like payload fairing after it was mounted on top of the rocket. Credit: USAF 30th Space Wing/Alex Valdez

The Delta 2's payloads were encapsulated inside the rocket's nose cone on top of the launch pad's mobile gantry in a cramped clean room, whereas satellites riding newer U.S. launchers are closed up inside their fairings in more expansive offsite processing facilities, then transported to the pad.
...

ICESat 2 begins ice-surveying mission

Спойлер

ICESat 2 stands for Ice, Cloud and land Elevation Satellite 2, a follow-on to NASA's ICESat mission which measured global ice sheets from 2003 until 2009.

Featuring an improved laser instrument designed to provide more precise measurements than its predecessor, ICESat 2 will extend a data series which has shown ice is melting around the edges of Greenland and Antarctica, and is thinning in the oceans.

"What we learned from ICESat about the ice sheets of Greenland and Antarctica is that they are particularly losing ice around coastal areas, which means, one, that they were losing ice, and also two, it was probably tied to changes occuring in the ocean," said Tom Wagner, NASA's cryosphere program scientist.

That's important because ice conditions are linked to other factors that drive Earth's climate, such as currents and temperatures in the oceans. And rising sea levels could threaten cities along coastlines, according to scientists.

"In Antarctica and Greenland, we have about two-thirds of the Earth's fresh water," said Helen Fricker, a member of ICESat's science definition team at the Scripps Institution of Oceanography. "If all of that ice melted, we would raise global sea level on average by about 180 feet (54 feet), which is very significant."

Altimetry data collected by by the U.S.-French TOPEX/Poseidon and Jason series of satellites show the average global sea level rose by 77 millimeters (3 inches) from 1993 through 2017. Scientists will compare data from missions like ICESat 2 with gravity measurements from missions like GRACE-Follow On, which launched in May and is sensitive to the mass of the ice.

"ICESat 2 really is a revolutionary new tool for both land ice and sea ice research," said Tom Neumann, ICESat 2's deputy project scientist at NASA's Goddard Space Flight Center.

Read our earlier story (https://spaceflightnow.com/2018/09/14/scientists-eager-to-renew-global-ice-measurements-with-nasas-icesat-2-mission/) for a detailed report on ICESat's science objectives.

NASA has used satellites to look at ice for decades, but tracking ice coverage is easier than measuring the height, and estimating the thickness, of floating sea ice and ice caps covering land masses.

Rather than relying on a single laser beam, as ICESat did, the new mission will fire six laser beams down to Earth and measure the time it takes for the light to bounce off the surface and back to a telescope on-board the spacecraft. The results will yield information on the height and slope of the ice.

The ICESat 2 satellite was built by Northrop Grumman Innovation Systems, and its single instrument — the Advanced Topographic Laser Altimeter System, or ATLAS — was developed at NASA's Goddard Space Flight Center.

"ATLAS essentially acts like a stop watch," said Donya Douglas-Bradshaw, ATLAS instrument manager at Goddard. "The ATLAS laser fires 10,000 pulses per second with a trillion photons in each shot. Each time the laser fires, it starts the stop watch. It takes about 3.3 milliseconds for the beam to exit the instrument, reach the surface and return back to the telescope."

Only about a dozen or so photons will make it back to ICESat 2's receiving telescope, with the rest of the light scattering in the atmosphere or back into space.

The laser package "has the ability to time tag a single photon to billionth of a second accuracy," Douglas-Bradshaw said in a briefing with reporters. "This precision allows the instrument to detect annual changes in ice elevation on the order of half of a centimeter (0.2 inches)."

The photon-counting method is new, and development the ATLAS laser proved to be a challenge, delaying ICESat 2's launch more than two years, and adding several hundred million dollars to the mission's cost.

Ground controllers plan to open a protective door covering the ATLAS instrument's sensitive optics around a week after launch, followed by the switch-on of the ATLAS laser about a week after that, according to Doug McLennan, ICESat project manager at Goddard.

After around 60 days of commissioning, officials expect to declare ICESat 2 ready for science observations.

ICESat is designed for a three-year mission, but it carries enough fuel to remain useful for more than 10 years, McLennan said.

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Цитировать(https://img.novosti-kosmonavtiki.ru/29898.jpg)ULA‏Подлинная учетная запись @ulalaunch (https://twitter.com/ulalaunch) 17 сент. (https://twitter.com/ulalaunch/status/1041772732449476610)

Delta II launched its final mission on Saturday, but the memories live on. Use the #DeltaII (https://twitter.com/hashtag/DeltaII?src=hash) hashtag to share your favorite memory about this rocket for your chance to win a prize pack. We'll randomly select winners Sept 18, Sept 20 and Sept 24. (https://img.novosti-kosmonavtiki.ru/125513.png) (https://img.novosti-kosmonavtiki.ru/125513.png) (https://img.novosti-kosmonavtiki.ru/125513.png)

(https://img.novosti-kosmonavtiki.ru/170304.jpg)

ЦитироватьVandenberg launches ULA Delta II
30th Space Wing Public Affairs
Sept. 15, 2018 | 0:45

https://cdn.dvidshub.net/media/video/1809/DOD_106025638/DOD_106025638.mp4 (https://cdn.dvidshub.net/media/video/1809/DOD_106025638/DOD_106025638.mp4)
(video (https://cdn.dvidshub.net/media/video/1809/DOD_106025638/DOD_106025638.mp4) 0:45)

Цитировать(https://img.novosti-kosmonavtiki.ru/29931.jpg)Tory Bruno‏Подлинная учетная запись @torybruno (https://twitter.com/torybruno) 11 ч. назад (https://twitter.com/torybruno/status/1042350514111950848)

The Great Workhose, Delta II, ended her career with another Bullseye. #IceSat2 (https://twitter.com/hashtag/IceSat2?src=hash)

(https://img.novosti-kosmonavtiki.ru/169511.jpg)

ЦитироватьRocket Cam! Delta II ICESat-2

United Launch Alliance (https://www.youtube.com/channel/UCnrGPRKAg1PgvuSHrRIl3jg)

Опубликовано: 20 сент. 2018 г.

Rocket's eye view of NASA's Ice, Cloud and land Elevation Satellite (ICESat)-2 mission from ULA's Delta II rocket.

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 21 сент. (https://twitter.com/NASA_ICE/status/1043223751729602560)

Week 1 update: #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) is looking great! (https://img.novosti-kosmonavtiki.ru/125382.png)(https://img.novosti-kosmonavtiki.ru/125535.png) Solar array deployed, all subsystems turned on, and we're busy checking everything out. Navigation works perfectly, guiding us along our planned orbit. ~1 week until it's time to open the door & turn on the laser!

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE ‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 42 мин. назад (https://twitter.com/NASA_ICE/status/1046064573189623813)

Our door is open! (https://img.novosti-kosmonavtiki.ru/125535.png)(https://img.novosti-kosmonavtiki.ru/125527.png)(https://img.novosti-kosmonavtiki.ru/125382.png)
The ATLAS instrument on #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) was designed with a door to protect the instrument as it settles into orbit – this morning the operations team successfully issued the commands to open the door and start letting the light in!

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 12 ч. назад (https://twitter.com/NASA_ICE/status/1046458132954779649)

The #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) laser is on, and has fired its first photons! 10,000 pulses each second, hundreds of trillions of photons with each pulse- all to measure the height of (https://img.novosti-kosmonavtiki.ru/125296.png)'s surface.
#pewpewpew (https://twitter.com/hashtag/pewpewpew?src=hash)

ЦитироватьOct. 3, 2018

ICESat-2 Laser Fires for 1st Time, Measures Antarctic Height

The laser instrument that launched into orbit last month aboard NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) fired for the first time Sept. 30. With each of its 10,000 pulses per second, the instrument is sending 300 trillion green photons of light to the ground and measuring the travel time of the few that return: the method behind ICESat-2's mission to monitor Earth's changing ice. By the morning of Oct. 3, the satellite returned its first height measurements across the Antarctic ice sheet.

Спойлер

"We were all waiting with bated breath for the lasers to turn on and to see those first photons return," said Donya Douglas-Bradshaw, the project manager for ICESat-2's sole instrument, called the Advanced Topographic Laser Altimeter System, or ATLAS. "Seeing everything work together in concert is incredibly exciting. There are a lot of moving parts and this is the demonstration that it's all working together."

ICESat-2 launched on Sept. 15 to precisely measure heights and how they change over time. It does this by timing how long it takes individual photons to leave the satellite, reflect off the surface, and return to receiver telescope on the satellite. The ATLAS instrument can time photons with a precision of less than a billionth of a second, which allows the mission to detect small changes in the planet's ice sheets, glaciers and sea ice.

https://www.youtube.com/watch?v=aYRqkdYJRr0 (https://www.youtube.com/watch?v=aYRqkdYJRr0)
(video (https://www.youtube.com/watch?v=aYRqkdYJRr0) 2:48)
Pho, a plucky bright green photon of light, must travel from a NASA spacecraft down to Earth and back again to help complete a crucial science mission in this educational short film. The animation was created and produced by media art students from the Savannah College of Art in Design in Georgia, in collaboration with ICESat-2.
Credits: NASA/Goddard/Savannah College of Art and Design et al
Download this video in HD formats from NASA Goddard's Scientific Visualization Studio (http://svs.gsfc.nasa.gov/12525)

Once ICESat-2 was in space, the ATLAS team waited to turn on the lasers for about two weeks to allow any Earthly contaminants or gases to dissipate.

"It's very critical when you fire the lasers that you don't have contaminants because you could damage the optics," Douglas-Bradshaw said. "Fourteen days is well beyond the time needed for that, but we wanted to be safe."

During those two weeks, the ICESat-2 operations team turned on and tested the various systems and subsystems of the spacecraft and instrument, and fired thrusters to start placing the satellite in its final polar orbit, approximately 310 miles (500 kilometers) above Earth.

Before the laser was even turned on, however, the team eagerly awaited another milestone, Douglas-Bradshaw said. The door that protected the telescope and detector elements during launch had to be opened. The team had two chances to release one of two spring-loaded pins to open the door. This was successfully accomplished on Sept. 29.

The following day, it was the laser's turn. The engineering team had been working with the operations team that controls the instrument on orbit, so the commands were ready to go — first turning on the laser itself, waiting for it to warm up, and then issuing commands to put it in fire mode.

The laser energy levels jumped up, and the device that starts ATLAS's sophisticated stopwatch was active — two different, independent indicators that the laser was firing away.

"We were all incredibly excited and happy, everyone was taking pictures of the screens showing data plots," Douglas-Bradshaw said. "Someone noted: 'Now we have a mission, now we have an instrument.'"

(https://img.novosti-kosmonavtiki.ru/208373.png) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat2firstphotonimagemap.png)
A visualization of ICESat-2 data, called a photon cloud, shows the first set of height measurements from the satellite, taken as it orbited over the Antarctic ice sheet. Each blue dot represents a photon detected by the ATLAS instrument. This photon cloud shows the elevation measured by photons in the middle of the ice sheet, following along 6.2 miles (10 kilometers) of the satellite's ground track, from left to right. The speckled dots are background photons from sunlight, but the thick blue line is actually a concentration of dots that represent laser photons that returned to the ICESat-2 satellite.
Credits: NASA's Goddard Space Flight Center

Three days later, the ICESat-2 team had the first segment of height data, taken as the satellite flew over Antarctica.

Computer programmers were up all night analyzing the latitude, longitude and elevation represented by each photon that returned to the ATLAS instrument — and by 6 a.m., Tom Neumann, ICESat-2 deputy project scientist, was texting screenshots of the height data to the rest of the team.

"It was awesome," Neumann said. "Having it in space, and not just simulating data on the ground, is amazing. This is real light that went from ATLAS to Earth and back again."

When scientists analyze the preliminary ICESat-2 data, they examine what is called a "photon cloud," or a plot of each photon that ATLAS detects. Many of the points on a photon cloud are from background photons — natural sunlight reflected off Earth in the exact same wavelength as the laser photons. But with the help of computer programs that analyze the data, scientists can extract the signal from the noise and identify height of the ground below.

The first photon cloud generated by ICESat-2 shows a stretch of elevation measurements from East Antarctica, passing close to the South Pole at a latitude of 88 degrees south, then continuing between Thwaites Glacier and Pine Island Glacier in West Antarctica.

https://www.youtube.com/watch?time_continue=2&v=bNsOBCd7cFs (https://www.youtube.com/watch?time_continue=2&v=bNsOBCd7cFs)
(video (https://www.youtube.com/watch?time_continue=2&v=bNsOBCd7cFs) 3:23)
Opto-Mechanical Engineer Tyler Evans explains how the photons that bounce back from Earth are received and filtered by the ATLAS telescope. ATLAS is the primary instrument on board the ICESat-2 spacecraft, which measures the height of Earth's features.
Credits: NASA's Goddard Space Flight Center
Download this video in HD formats from NASA Goddard's Scientific Visualization Studio (https://svs.gsfc.nasa.gov/11726#22340)

Next up for ICESat-2 is a suite of procedures to optimize the instrument, Neumann said, including tests to ensure the laser is pointing at the precisely correct angle and lasing at the precisely correct wavelength to allow as many photons as possible to hit the detector.

"It will take a couple of additional weeks," he said, "but about one month after launch we'll hopefully start getting back some excellent science-quality data."

ICESat-2 launched from Vandenberg Air Force Base on the final United Launch Alliance Delta II rocket. The spacecraft was built by Northrop Grumman, which also controls the observatory from their Mission Operations Center in Dulles, Virginia.

By Kate Ramsayer (mailto:kate.d.ramsayer@nasa.gov?subject=RE%20ICESat%202%20Returns%20First%20Measurements)
NASA's Goddard Space Flight Center (http://www.nasa.gov/goddard), Greenbelt, Md.

[свернуть]

Last Updated: Oct. 3, 2018
Editor: Rob Garner

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 21 ч. назад (https://twitter.com/NASA_ICE/status/1047566453917044737)

Take a look (https://img.novosti-kosmonavtiki.ru/125368.png) at the first photon returns from #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash)'s six beams as it orbits over Antarctica! The green lines are number of photons detected, while the X-axis shows how long (https://img.novosti-kosmonavtiki.ru/125589.png) it took the photons to get from ICESat-2 (https://img.novosti-kosmonavtiki.ru/125535.png) to the ground and back!

https://video.twimg.com/tweet_video/Dom0EOXX0AAWIob.mp4 (https://video.twimg.com/tweet_video/Dom0EOXX0AAWIob.mp4)
(video (https://video.twimg.com/tweet_video/Dom0EOXX0AAWIob.mp4) 0:12)

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 3 мин. назад (https://twitter.com/NASA_ICE/status/1048293387550580736)

The #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) photons keep returning! A set of height measurements (https://img.novosti-kosmonavtiki.ru/125418.png) over a boreal forest in Siberia shows the laser light reflecting from both the leaves/branches of trees & the forest floor (courtesy of K.Harbeck). https://go.nasa.gov/2ybKUyt  (https://t.co/w9LmFYlOB7) (https://img.novosti-kosmonavtiki.ru/125535.png)(https://img.novosti-kosmonavtiki.ru/125319.png)(https://img.novosti-kosmonavtiki.ru/125297.png)

(https://img.novosti-kosmonavtiki.ru/170960.jpg)

Цитировать(https://img.novosti-kosmonavtiki.ru/185429.jpg)NASA ICE‏Подлинная учетная запись @NASA_ICE (https://twitter.com/NASA_ICE) 17 ч. назад (https://twitter.com/NASA_ICE/status/1050124461641555969)

Check out how #ICESat2 (https://twitter.com/hashtag/ICESat2?src=hash) (https://img.novosti-kosmonavtiki.ru/125535.png) sees sea ice! Here's a first look at photon returns over the North Atlantic and Arctic oceans near Svalbard, showing heights where open water (red arrows) breaks up chunks of floating ice (courtesy K. Harbeck)

(https://img.novosti-kosmonavtiki.ru/171241.jpg)

ЦитироватьOct. 12, 2018

Operation IceBridge, ICESat-2 Join Forces To Survey Antarctica

NASA's decade-long airborne survey of polar ice, Operation IceBridge, is once again probing Antarctica. But this year is different: it is the first time that the IceBridge team and instruments survey the frozen continent while NASA's newest satellite mission, the Ice, Cloud and land Elevation Satellite-2 (ICESat-2), studies it fr om space.

After successfully flying over the Bailey Ice Stream and Slessor Glacier in East Antarctica on Oct. 10, IceBridge will spend the next five weeks measuring changes in Antarctic sea and land ice while precisely flying under orbits of ICESat-2 to compare measurements.

Спойлер

IceBridge began flying in 2009 to maintain continuity of laser-altimetry measurements between NASA's ICESat missions. The original ICESat mission ended in 2009, and its successor, ICESat-2, was launched this past Sept. 15. Since then, ICESat-2 has successfully collected its first height measurements across the Antarctic Ice Sheet on Oct. 3.

"After a decade of flying both poles every year, we're finally bridging the two ICESat satellite missions," said Joe MacGregor, IceBridge's project scientist and a glaciologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's hugely satisfying to be part of building this key observational record of change in the polar regions."

(https://img.novosti-kosmonavtiki.ru/207604.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/6_shackleton_sunset.jpg)
The Shackleton Range in Antarctica at sunset with snow blowing off the ridges, photographed during an Operation IceBridge flight on Oct. 10, 2018.
Credits: NASA/Michael Studinger

"This campaign is our second-to-last Antarctic campaign and it is arguably the most scientifically diverse that IceBridge has ever done," MacGregor said. "We're going to be revisiting classic IceBridge targets: flights along glacier flowlines that have been surveyed since 2002, long-term sea ice flights, and new targets across West Antarctica. More than two dozen of these mission designs are relevant to both IceBridge and ICESat-2."

IceBridge and ICESat-2 both use laser altimeters that fire pulses of light toward the ground and measure how long it takes for that light to bounce off the ice and return to the instruments' sensors. Scientists can then calculate the distance between the aircraft or the satellite and the ice surface, which gives them the ice height.

When IceBridge flies along a track over Antarctica that ICESat-2 has either just or is about to pass over as it orbits in space, pilots will align the plane so that the swath fired by IceBridge's laser altimeter encompasses the tracks of two of ICESat-2's six laser beams. Researchers will then look for overlap between the IceBridge and ICESat-2 returns and compare their measurements of ice height.

(https://img.novosti-kosmonavtiki.ru/207770.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/icesat2icebridgefootprints.jpg)
IceBridge's Airborne Topographic Mapper instrument, or ATM, has two lasers that shoot thousands of pulses of light per second in a circular motion that, combined with the plane's forward motion, result in spiral patterns of height measurements over Earth's surface. At the altitude that IceBridge typically conducts polar surveys, the lasers' swaths are 650 feet and 130 feet wide, respectively. Each single measurement, or laser pulse, for either instrument has a 3-foot footprint on the ground. In contrast, ICESat-2 takes measurements following six unique lines on the ground, one for each of its laser beams. The footprint of each ICESat-2 laser pulse is about 56 feet in diameter.
Credits: NASA/Kelly Brunt, Adriana Manrique

During this year's Antarctic campaign, the IceBridge team will fly under some of ICESat-2's orbits over sea and land ice. The underflights over sea ice to collect measurements of freeboard — the total height of the snow cover and sea ice that floats above the ocean — are particularly tricky. The ice that floats over the Southern Ocean is in constant motion, so in order to survey the same patches of sea ice that ICESat-2 will have flown over a few hours earlier or later that day, the IceBridge scientists will first have to figure out where that sea ice has drifted.

(https://img.novosti-kosmonavtiki.ru/208189.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/2_filchner_polynya.jpg)
A coastal polynya, or opening in the sea ice cover, near the Filchner Ice Shelf in Antarctica, as seen during an Operation IceBridge flight on Oct. 10, 2018.
Credits: NASA/John Sonntag

"We're going to be chasing sea ice," said Linette Boisvert, IceBridge's deputy project scientist and a sea ice researcher at Goddard. "To do so, we will take the plane down to a lower altitude and remain there for a few seconds to measure wind speed and direction. We'll plug these data into a code that accounts for drift and other forces, calculating where the sea ice that ICESat-2 flew over is currently located. Then, we'll adjust our route to fly over it. On the way back to base, we'll drop lower again to measure wind speed, readjust our trajectory and chase sea ice again."

Another modification to meet ICESat-2's needs will be performing a sea ice survey at twilight. Normally, IceBridge only conducts its flights in broad daylight, but, since ICESat-2 will be taking measurements around the clock, the scientists want to check whether laser data are more accurate at low light, when there is less interference on the laser instrument's sensors from the Sun.

Over land ice, IceBridge will retrace some of ICESat-2's tracks over the ice sheet and its outlet glaciers, with a particular interest in areas of blue ice. Those are sections of the ice sheet wh ere the wind has scoured the snow off and exposed nearly pure ice. The intercomparison of measurements of blue ice, with no snow interference, will help ICESat-2 researchers understand how much the laser signal can penetrate ice.

While flying over Antarctica, IceBridge will also collaborate with satellite missions and international research groups as weather and time allow. During the sea ice surveys, the IceBridge plane may also fly under the tracks of ESA's (European Space Agency) CryoSat-2 and the European Union's Sentinel-3 satellites. During a survey flight over Thwaites Glacier, one of the fastest-changing glaciers in West Antarctica, IceBridge may collect seafloor measurements to support the International Thwaites Glacier Collaboration, a joint campaign between the United States and the United Kingdom.

This year, IceBridge flights to Antarctica will begin first from Punta Arenas, in southern Chile, and later from Ushuaia, in southern Argentina. The surveys will be conducted from NASA's DC-8 airborne science laboratory. The plane, managed by NASA's Armstrong Flight Research Center in Palmdale, California, carries IceBridge's full instrument suite.

IceBridge's main instrument is a dual-color laser altimeter from NASA's Wallops Flight Facility in Virginia that measures surface elevation by transmitting both infrared and green laser pulses. The airborne mission also uses two types of radar systems from the Center for Remote Sensing of Ice Sheets at the University of Kansas to study ice layers and Antarctica's bedrock. Wallops also contributes a high-resolution camera to collect color images of the ice surface and infrared cameras to read surface temperatures of sea and land ice. Goddard provides a hyperspectral imager to the mission that takes measurements over hundreds of wavelengths and Columbia University in New York manages a gravimeter to map the seafloor underneath the ice shelves.

[свернуть]

Last Updated: Oct. 12, 2018
Editor: Rob Garner

ЦитироватьDec. 11, 2018

ICESat-2 Reveals Profile of Ice Sheets

(https://img.novosti-kosmonavtiki.ru/207497.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/seaice11.jpg)

Less than three months into its mission, NASA's Ice, Cloud and land Elevation Satellite-2 (https://www.nasa.gov/content/goddard/icesat-2), or ICESat-2, is already exceeding scientists' expectations. The satellite is measuring the height of sea ice to within an inch, tracing the terrain of previously unmapped Antarctic valleys, surveying remote ice sheets, and peering through forest canopies and shallow coastal waters.

With each pass of the ICESat-2 satellite (https://www.nasa.gov/feature/goddard/2018/icesat-2-reveals-profile-of-ice-sheets-sea-ice-forests), the mission is adding to datasets tracking Earth's rapidly changing ice. Researchers are ready to use the information to study sea level rise resulting from melting ice sheets and glaciers, and to improve sea ice and climate forecasts.

In this image, sea ice forms in the open water between floes, called leads, in the Bellingshausen Sea. ICESat-2 is able to detect the thin sea ice, allowing scientists to more accurately track seasonal ice formation.

Image Credit: NASA/Kate Ramsayer

Last Updated: Dec. 11, 2018
Editor: Yvette Smith

ЦитироватьNew NASA Satellite Reveals Profiles of Ice, Forests and Oceans

NASA Goddard (https://www.youtube.com/channel/UCAY-SMFNfynqz1bdoaV8BeQ)

Опубликовано: 11 дек. 2018 г.

Спойлер

Less than three months into its mission, NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, is already exceeding scientists' expectations. The satellite is measuring the height of sea ice to within an inch, tracing the terrain of previously unmapped Antarctic valleys, surveying remote ice sheets, and peering through forest canopies and shallow coastal waters.

With each pass of the ICESat-2 satellite, the mission is adding to datasets tracking Earth's rapidly changing ice. Researchers are ready to use the information to study sea level rise resulting from melting ice sheets and glaciers, and to improve sea ice and climate forecasts.

[свернуть]

ЦитироватьDec. 11, 2018

ICESat-2 Reveals Profile of Ice Sheets, Sea Ice, Forests

Less than three months into its mission, NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, is already exceeding scientists' expectations. The satellite is measuring the height of sea ice to within an inch, tracing the terrain of previously unmapped Antarctic valleys, surveying remote ice sheets, and peering through forest canopies and shallow coastal waters.

With each pass of the ICESat-2 satellite, the mission is adding to datasets tracking Earth's rapidly changing ice. Researchers are ready to use the information to study sea level rise resulting fr om melting ice sheets and glaciers, and to improve sea ice and climate forecasts.

"ICESat-2 is going to be a fantastic tool for research and discovery, both for cryospheric sciences and other disciplines," said Tom Neumann, ICESat-2 project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Neumann and others with ICESat-2's science team shared the first look at the satellite's findings at the American Geophysical Union's annual meeting on Tuesday in Washington, D.C.

Filling in the gaps

Спойлер

In topographic maps of Transantarctic Mountains, which divide East and West Antarctica, there are places where other satellites just can't see. Some instruments don't orbit that far south, others only pick up large features or the highest points and so miss minor peaks and valleys. With an early pass of ICESat-2, scientists started to fill in those details.

"It's spectacular terrain," said Benjamin Smith, a glaciologist with the University of Washington, Seattle, and member of the ICESat-2 science team. "We're able to measure slopes that are steeper than 45 degrees, and maybe even more, all through this mountain range."

As ICESat-2 orbits over the Antarctic Ice Sheet, the photon returns reflect fr om the surface and show high ice plateaus, crevasses in the ice 65 feet (20 meters) deep, and the sharp edges of ice shelves dropping into the ocean. These first measurements can help fill in the gaps of Antarctic maps, Smith said, but the key science of the ICESat-2 mission is yet to come. As researchers refine knowledge of where the instrument is pointing, they can start to measure the rise or fall of ice sheets and glaciers.

"Very soon, we'll have measurements that we can compare to older measurements of surface elevation," Smith said. "And after the satellite's been up for a year, we'll start to be able to watch the ice sheets change over the seasons."

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On thin ice

Спойлер

When sea ice first forms on polar oceans, before snow falls on it and wind smashes it into other floes, it is thin, flat and smooth. Which makes it a good place to test out how precise ICESat-2 data is, since long stretches should all be nearly the same height, said Ron Kwok, a sea ice scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. 
 
(https://img.novosti-kosmonavtiki.ru/207647.png) (https://www.nasa.gov/sites/default/files/thumbnails/image/antarctica_ice2_2018.png)
As ICESat-2 orbited over Antarctica, it took height measurements over the steep Queen Maud Mountains - some of which had never been previously measured. Over the Ross Ice Shelf, the photon return data showed a mostly flat surface, broken by terrain including the Crary Ice Rise.
Credits: NASA Earth Observatory/Joshua Stevens

So far? "The data's spectacular," Kwok said. "The fresh ice is totally flat to within a couple centimeters."

The first months of ICESat-2 data collected over Arctic and Antarctic sea ice reveal thin ice, thick ice, and features such as ice ridges. Areas of open water in the cracks between the ice floes, called leads, stand out in the data because of the difference in reflectivity between ice and water. By comparing the height of that water surface in the leads with the height of the ice, scientists are estimating ice freeboard and thickness. With the high precision of ICESat-2, plus the satellite's six beams taking data simultaneously, researchers will have an unprecedented understanding of the thickness of sea ice, which will be used to help improve climate modeling and forecasts.

Plus, the ability to identify newly formed, thin ice will help researchers track the seasonal changes in remote polar regions, and understand the processes that drive those processes. The ice-thickness data will also help scientists improve computer models of how sea ice responds to Arctic warming, as well as forecasts of sea ice cover.

"We'll have much higher resolution of where it's ice and where it's water in the marginal ice zones, wh ere the compact ice cover meets the ocean, during melt and freeze-up," Kwok said. "That's going to be new science to think about. "

[свернуть]

Beyond ice

Спойлер

ICESat-2 is always on, taking measurements not only at the poles but also in the tropical and temperate latitudes, and what it can see has already surprised researchers.

(https://img.novosti-kosmonavtiki.ru/208142.png) (https://www.nasa.gov/sites/default/files/thumbnails/image/weddell_ice2_2018_highres.png)
Sea ice of different thickness and bumpiness is broken up by the cracks between floes, called leads, in this graph of photon returns from ICESat-2 as it orbits over the Weddell Sea in Antarctica.
Credits: NASA Earth Observatory/Joshua Stevens

"We were all taken aback seeing the amazing detail from ICESat-2, thanks to its detection technology," said Lori Magruder, a research scientist at the University of Texas and the ICESat-2 science team lead. "On every surface, there was some amazing feature that we weren't used to seeing with the first ICESat."

For example, photons returning from over the ocean trace individual waves. In clear coastal areas, the bathymetry is visible, sometimes as deep as 80 feet (25 meters), which could help with research including storm surge modeling, Magruder said. 

And as ICESat-2 orbits over forests, it can distinguish not only the tops of trees but also the inner canopies and the forest floor. While the team was unsure how clear the terrain would be under dense canopies like those found in tropical rainforests, the data turned out even better than expected. By measuring tree heights globally, the ICESat-2 mission will be able to improve estimates of how much carbon is stored in forests.

[свернуть]

Checking the numbers, bridging the gap

Спойлер

As the ICESat-2 science team was analyzing the first sets of data, colleagues with NASA's Operation IceBridge were collecting data in aircraft over Antarctica – flying over the same paths that the satellite was orbiting.

(https://img.novosti-kosmonavtiki.ru/207898.png) (https://www.nasa.gov/sites/default/files/thumbnails/image/mexico_ice2_2018_highres.png)
ICESat-2 is on all the time - and so takes height measurements over land, forests and oceans as well as ice. As it orbited over Mexico, the satellite measurements who the height of trees as well as the forest floor, plus the bathymetry of a lagoon and the ocean waves beyond.
Credits: NASA Earth Observatory/Joshua Stevens

Over vast plains of rippling ice, craggy peaks poking through the ice sheet, and lines of crevasses marching down glaciers, the airborne campaign measured surface elevation with the Airborne Topographic Mapper's laser altimeters, snow and ice thickness with radars, and sub-ice-shelf bathymetry with a gravimeter. For a decade, IceBridge has been surveying the region, but this fall they were also gathering data to help check the accuracy of ICESat-2.

In three separate flights, IceBridge surveyed the flat plateau along the 88-degree-south latitude line wh ere all ICESat-2 orbits converge. Other flights tracked across glaciers, ice streams and mountains along individual satellite paths – at times right as the satellite passed overhead. To measure sea ice, the IceBridge team flew briefly at 500 feet to measure wind speed, calculated how far the ice had moved since ICESat-2 measured it, and then adjusted the flight path to survey the same patch of ice.

"Almost every flight has ICESat-2 tracks incorporated into it," said Joseph MacGregor, IceBridge project scientist at NASA Goddard. "We fly over fast-changing outlet glaciers, the slower-changing interior, and uncommon surfaces that are interesting to ICESat-2. The primary goal for IceBridge is to bridge the gap between ICESat and ICESat-2, so it's very rewarding to know that we're completing that process."

The first ICESat satellite operated between 2003 and 2009, which is when IceBridge began its campaigns. ICESat-2 launched on Sept. 15 from Vandenberg Air Force Base in California. Its laser instrument, called ATLAS (Advanced Topographic Laser Altimeter System), sends pulses of light to Earth. It then times, to within a billionth of a second, how long it takes individual photons to return to the satellite. ATLAS has fired its laser more than 50 billion times since first turning on Sept. 30, and all the metrics from the instrument show it is working as it should, Neumann said.

[свернуть]

Mission managers expect to release the data to the public in early 2019.

Credits: Kate Ramsayer

By Kate Ramsayer (mailto:kate.d.ramsayer@nasa.gov?subject=Re%3A%20Ice)
NASA's Goddard Space Flight Center (http://www.nasa.gov/goddard), Greenbelt, Md. 

Last Updated: Dec. 13, 2018
Editor: Sara Blumberg

ЦитироватьMeasuring Sea Ice Thickness With ICESat-2

(https://img.novosti-kosmonavtiki.ru/220350.jpg) (https://www.youtube.com/user/NASAgovVideo) NASA Video (https://www.youtube.com/channel/UC_aP7p621ATY_yAa8jMqUVA)

14 мая 2020 г.

A view of the Arctic Ocean with monthly average sea ice thickness spanning November 2018 to March 2019. Low values are depicted in light blue, and higher values (5 meters) are depicted in magenta.

ЦитироватьMay 14, 2020

NASA's ICESat-2 Measures Arctic Ocean's Sea Ice Thickness, Snow Cover

Arctic sea ice helps keep Earth cool, as its bright surface reflects the Sun's energy back into space. Each year scientists use multiple satellites and data sets to track how much of the Arctic Ocean is covered in sea ice, but its thickness is harder to gauge. Initial results from NASA's new Ice Cloud and land Elevation Satellite-2 (ICESat-2) suggest that the sea ice has thinned by as much as 20% since the end of the first ICESat mission (2003-2009), contrary to existing studies that find sea ice thickness has remained relatively constant in the last decade.

ICESat-2 has a laser altimeter, which uses pulses of light to precisely measure height down to about an inch. Each second, the instrument sends out 10,000 pulses of light that bounce off the surface of Earth and return to the satellite and records the length of time it takes to make that round trip. The light reflects off the first substance it hits, whether that's open water, bare sea ice or snow that has accumulated on top of the ice, so scientists use a combination of ICESat-2 measurements and other data to calculate sea ice thickness.

By comparing ICESat-2 data with measurements from another satellite, researchers have also created the first satellite-based maps of the amount of snow that has accumulated on top of Arctic sea ice, tracking this insulating material.

"The Arctic sea ice pack has changed dramatically since monitoring from satellites began more than four decades ago," said Nathan Kurtz, ICESat-2 deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The extraordinary accuracy and year-round measurement capability of ICESat-2 provides an exciting new tool to allow us to better understand the mechanisms leading to these changes, and what this means for the future."

(https://img.novosti-kosmonavtiki.ru/208065.jpg) (https://www.nasa.gov/sites/default/files/thumbnails/image/seaice2019harbeck.jpg)
Scientists have used NASA's ICESat-2 to measure the thickness of Arctic sea ice, as well as the depth of snow on the ice. Here, ridges and cracks have formed in sea ice in the Arctic Ocean.
Credits: NASA / Jeremy Harbeck

Arctic sea ice thickness dropped drastically in the first decade of the 21st Century, as measured by the first ICESat mission from 2003 to 2009 and other methods. The European Space Agency's CryoSat-2, launched in 2010, has measured a relatively consistent thickness in Arctic sea ice since then. With the launch of ICESat-2 in 2018, researchers looked to this new way of measuring sea ice thickness to advance the study of this data record.

"We can't get thickness just from ICESat-2 itself, but we can use other data to derive the measurement," said Petty. For example, the researchers subtract out the height of snow on top of the sea ice by using computer models that estimate snowfall. "The first results were very encouraging."

In their study (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JC015764), published recently in the Journal of Geophysical Research: Oceans, Petty and his colleagues generated maps of Arctic sea ice thickness from October 2018 to April 2019 and saw the ice thickening through the winter as expected.

Overall, however, calculations using ICESat-2 found that the ice was thinner during that time period than what researchers have found using CryoSat-2 data. Petty's group also found that small but significant 20% decline in sea ice thickness by comparing February/March 2019 ICESat-2 measurements with those calculated using ICESat in February/March 2008 – a decline that the CryoSat-2 researchers don't see in their data.

These are two very different approaches to measuring sea ice, Petty said, each with its own limitations and benefits. CryoSat-2 carries a radar to measure height, as opposed to ICESat-2's lidar, and radar mostly passes through snow to measure the top of the ice. Radar measurements like the ones from CryoSat-2 could be thrown off by seawater flooding the ice, he noted. In addition, ICESat-2 is still a young mission and the computer algorithms are still being refined, he said, which could ultimately change the thickness findings.

"I think we're going to learn a lot from having these two approaches to measuring ice thickness. They might be giving us an upper and lower bound on the sea ice thickness, and the right answer is probably somewhere in between," Petty said. "There are reasons why ICESat-2 estimates could be low, and reasons why CryoSat-2 could be high, and we need to do more work to understand and bring these measurements in line with each other."

With ICESat-2 and CryoSat-2 using two different methods to measure ice thickness – one measuring the top of the snow, the other the boundary between the bottom of the snow layer and the top of the ice layer – but researchers realized they could combine the two to calculate the snow depth.

"This is the first time ever that we can get snow depth across the entire Arctic Ocean's sea ice cover," said Ron Kwok, a sea ice scientist at NASA's Jet Propulsion Laboratory in Southern California and author of another study (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JC016008) in JGR Oceans. "The Arctic region is a desert – but what snow we do get is very important in terms of the climate and insulating sea ice."

The study found that snow starts building up slowly in October, when newly formed ice has an average of about 2 inches (5 centimeters) of snow on it and multiyear ice has an average of 5.5 inches (14 cm) of snow. Snowfall picks up later in the winter in December and January and reaches its maximum depth in April, when the relatively new ice has an average of 6.7 inches (17 cm) and the older ice has an average of 10.6 inches (27 cm) of snow.

When the snow melts in the spring, it can pool up on the sea ice – those melt ponds absorb heat from the Sun and can warm up the ice faster, just one of the impacts of snow on ice.

By Kate Ramsayer (mailto:kate.d.ramsayer@nasa.gov)

NASA's Goddard Space Flight Center (http://www.nasa.gov/goddard), Greenbelt, Maryland

Last Updated: May 14, 2020
Editor: Kate Ramsayer