Автор Anatoly Zak, 26.05.2011 08:53:55

« предыдущая - следующая »

0 Пользователей и 1 гость просматривают эту тему.


ЦитатаTour of Asteroid Bennu

 NASA Goddard

8 окт. 2020 г.

When NASA's OSIRIS-REx spacecraft arrived at asteroid Bennu in December 2018, its close-up images confirmed what mission planners had predicted nearly two decades before: Bennu is made of loose material weakly clumped together by gravity, and shaped like a spinning top. This major validation, however, was accompanied by a major surprise. Scientists had expected Bennu's surface to consist of fine-grained material like a sandy beach, but were instead greeted by a rugged world littered with boulders - the size of cars, the size of houses, the size of football fields. Now, thanks to laser altimetry data and high-resolution imagery from OSIRIS-REx, we can take a tour of Bennu's remarkable terrain.


https://www.youtube.com/watch?v=QunVAWABQSc (4:53)



ЦитатаOct. 16, 2020

Ten Things to Know About Bennu

NASA's first mission to return a sample from an ancient asteroid arrived at its target, the asteroid Bennu, on Dec. 3, 2018. This mission, the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx, is a seven-year long voyage set to conclude upon the delivery to Earth of at least 2.1 ounces (60 grams) and possibly up to almost four and a half pounds (two kilograms) of sample. It promises to be the largest amount of extraterrestrial material brought back from space since the Apollo era. The 20-year anniversary of the asteroid's discovery was in September 2019 -- and scientists have been collecting data ever since. Here's what we already know (and some of what we hope to find out) about this pristine remnant from the early days of our solar system.

Now, thanks to laser altimetry data and high-resolution imagery from OSIRIS-REx, we can take a tour of Bennu's remarkable terrain.
Credits: NASA's Goddard Space Flight Center
This video is public domain and can be downloaded from the Scientific Visualization Studio.


Bennu is classified as a B-type asteroid, which means it contains a lot of carbon in and along with its various minerals. Bennu's carbon content creates a surface on the asteroid that reflects about four percent of the light that hits it -- and that's not a lot. For contrast, the solar system's brightest planet, Venus, reflects around 65 percent of incoming sunlight, and Earth reflects about 30 percent. Bennu is a carbonaceous asteroid that hasn't undergone drastic, composition-altering change, meaning that on and below its deeper-than-pitch-black surface are chemicals and rocks from the birth of the solar system.

This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2, 2018 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km).
Credits: NASA/Goddard/University of Arizona


Bennu has been (mostly) undisturbed for billions of years. Not only is it conveniently close and carbonaceous, it is also so primitive that scientists calculated it formed in the first 10 million years of our solar system's history -- over 4.5 billion years ago. Thanks to the Yarkovsky effect -- the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat -- and gravitational tugs from other celestial bodies, it has drifted closer and closer to Earth from its likely birthplace: the Main Asteroid Belt between Mars and Jupiter.


Is Bennu space trash or scientific treasure? While "rubble pile" sounds like an insult, it's actually a real astronomy classification. Rubble-pile asteroids like Bennu are celestial bodies made from lots of pieces of rocky debris that gravity compressed together. This kind of detritus is produced when an impact shatters a much larger body (for Bennu, it was a parent asteroid around 60 miles [about 100 km] wide). Bennu, for contrast, is about as tall as the Empire State Building. It likely took just a few weeks for these shards of space wreckage to coalesce into the rubble-pile that is Bennu. Bennu is full of holes inside, with 20 to 40 percent of its volume being empty space. The asteroid is actually in danger of flying apart, if it starts to rotate much faster or interacts too closely with a planetary body.


Bennu is a primordial artifact preserved in the vacuum of space, orbiting among planets and moons and asteroids and comets. Because it is so old, Bennu could be made of material containing molecules that were present when life first formed on Earth. All Earth life forms are based on chains of carbon atoms bonded with oxygen, hydrogen, nitrogen and other elements. However, organic material like the kind scientists hope to find in a sample from Bennu doesn't necessarily always come from biology. It would, though, further scientists' search to uncover the role asteroids rich in organics played in catalyzing life on Earth.


Extraterrestrial jewelry sounds great, and Bennu is likely to be rich in platinum and gold compared to the average crust on Earth. Although most aren't made almost entirely of solid metal (but asteroid 16 Psyche may be!), many asteroids do contain elements that could be used industrially in lieu of Earth's finite resources. Closely studying this asteroid will give answers to questions about whether asteroid mining during deep-space exploration and travel is feasible. Although rare metals attract the most attention, water is likely to be the most important resource in Bennu. Water (two hydrogen atoms bound to an oxygen atom) can be used for drinking or separated into its components to get breathable air and rocket fuel. Given the high cost of transporting material into space, if astronauts can extract water from an asteroid for life support and fuel, the cosmic beyond is closer than ever to being human-accessible.


Gravity isn't the only factor involved with Bennu's destiny. The side of Bennu facing the Sun gets warmed by sunlight, but a day on Bennu lasts just 4 hours and 17.8 minutes, so the part of the surface that faces the Sun shifts constantly. As Bennu continues to rotate, it expels this heat, which gives the asteroid a tiny push towards the Sun by about 0.18 miles (approximately 0.29 kilometers) per year, changing its orbit.


The NASA-funded Lincoln Near-Earth Asteroid Research team discovered Bennu in 1999. NASA's Planetary Defense Coordination Office continues to track near-Earth objects (NEOs), especially those like Bennu that will come within about 4.6 million miles (7.5 million kilometers) of Earth's orbit and are classified as potentially hazardous objects. Between the years 2175 and 2199, the chance that Bennu will impact Earth is only 1-in-2,700, but scientists still don't want to turn their backs on the asteroid. Bennu swoops through the solar system on a path that scientists have confidently predicted, but they will refine their predictions with the measurement of the Yarkovsky Effect by OSIRIS-REx and with future observations by astronomers.


Early Earth-based observations of the asteroid suggested it had a smooth surface with a regolith (the top layer of loose, unconsolidated material) composed of particles less than an inch (a couple of centimeters) large -- at most. As the OSIRIS-REx spacecraft was able to take pictures with higher resolution, it became evident that sampling Bennu would be far more hazardous than what was previously believed: new imagery of Bennu's surface show that it's mostly covered in massive boulders, not small rocks. OSIRIS-REx was designed to be navigated within an area on Bennu of nearly 2,000 square yards (meters), roughly the size of a parking lot with 100 spaces. Now, it must maneuver to a safe spot on Bennu's rocky surface within a constraint of less than 100 square yards, an area of about five parking spaces.

Captured on Aug. 11, 2020 during the second rehearsal of the OSIRIS-REx mission's sample collection event, this series of images shows the SamCam imager's field of view as the NASA spacecraft approaches asteroid Bennu's surface. The rehearsal brought the spacecraft through the first three maneuvers of the sampling sequence to a point approximately 131 feet (40 meters) above the surface, after which the spacecraft performed a back-away burn.
Credits: NASA/Goddard/University of Arizona

Full story


Bennu was named in 2013 by a nine-year-old boy from North Carolina who won the Name that Asteroid! competition, a collaboration between the mission, the Planetary Society, and the LINEAR asteroid survey that discovered Bennu. Michael Puzio won the contest by suggesting that the spacecraft's Touch-and-Go Sample Mechanism (TAGSAM) arm and solar panels resemble the neck and wings in illustrations of Bennu, whom ancient Egyptians usually depicted as a gray heron. Bennu is the ancient Egyptian deity linked with the Sun, creation and rebirth -- Puzio also noted that Bennu is the living symbol of Osiris. The myth of Bennu suits the asteroid itself, given that it is a primitive object that dates back to the creation of the Solar System. Themes of origins and rebirth are part of this asteroid's story. Birds and bird-like creatures are also symbolic of rebirth, creation and origins in various ancient myths.


The spacecraft's navigation camera observed that Bennu was spewing out streams of particles a couple of times each week. Bennu apparently is not only a rare active asteroid (only a handful of them have been as of yet identified), but possibly with Ceres explored by NASA's Dawn mission, among the first of its kind that humanity has observed from a spacecraft. More recently, the mission team discovered that sunlight can crack rocks on Bennu, and that it has pieces of another asteroid scattered across its surface. More pieces will be added to Bennu's cosmic puzzle as the mission progresses, and each brings the solar system's evolutionary history into sharper and sharper focus.
Particles ejected from Bennu
This view of asteroid Bennu ejecting particles from its surface on January 19, 2019 was created by combining two images taken on board NASA's OSIRIS-REx spacecraft. Other image processing techniques were also applied, such as cropping and adjusting the brightness and contrast of each image.
Credits: NASA/Goddard/University of Arizona/Lockheed Martin
Full story

Goddard provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission's science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the agency's Science Mission Directorate in Washington.

Last Updated: Oct. 16, 2020
Editor: Bill Steigerwald



ЦитатаOSIRIS-REX Mission Update on the Science of Capturing an Asteroid Sample

Начало трансляции - 19 октября 2020 г. в 19:00 UTC / 22:00 ДМВ



ЦитатаLive Q&A: How NASA Plans to Collect a Sample from Asteroid Bennu

Начало трансляции - 19 октября 2020 г. в 21:00 UTC / 20 октября 2020 г. в 00:00 ДМВ


19.10.2020 17:10:44 #704 Последнее редактирование: 20.10.2020 21:09:34 от tnt22
АНОНС - трансляция попытки взятия проб грунта с поверхности астероида Бенну

ЦитатаWatch NASA's OSIRIS-REx Spacecraft Attempt to Capture a Sample of Asteroid Bennu

Начало трансляции - 20 октября 2020 г. в 21:00 UTC / 21 октября 2020 г. в 00:00 ДМВ


Медиа телеконференция - в аудиоэфире

ЦитатаNASA Live: Asteroid Science and Planetary Defense Media Telecon (Oct. 19, 2020)


19.10.2020 22:11:04 #706 Последнее редактирование: 19.10.2020 22:16:24 от tnt22
#702 - статус мероприятия изменён на аудиоконференцию

адрес трансляции - youtu.be/rNZjogVTmAM

ЦитатаEditor's note, Oct. 19, 2020: the 3 p.m. briefing will be a teleconference streamed via this webpage, not televised on NASA.gov.

3 p.m. -  OSIRIS-REx Science and Engineering media teleconference briefing with the following participants:

  • Thomas Zurbuchen, associate administrator, Science Mission Directorate, NASA Headquarters, Washington
  • Lori Glaze, Planetary Science Division director, NASA Headquarters
  • Heather Enos, OSIRIS-REx deputy principal investigator, University of Arizona, Tucson
  • Kenneth Getzandanner, OSIRIS-REx flight dynamics manager, Goddard
  • Beth Buck, OSIRIS-REx mission operations program manager, Lockheed Martin Space, Littleton, Colorado


ЦитатаLive Q&A: How NASA Plans to Collect a Sample from Asteroid Bennu


Трансляция началась 42 минуты назад

On Oct. 20, NASA will attempt to maneuver the OSIRIS-REx spacecraft down to touch the surface of asteroid Bennu and collect a sample. Join NASA's Dr. Z and Dr. Glaze as we gear up for this historic event and ask them your questions


https://www.youtube.com/watch?v=msLV_NydC0g (28:33)



Цитата20 ОКТ, 02:00
Зонд OSIRIS-REx попытается забрать грунт с астероида Бенну
Эксперты рассчитывают, что зонд соберет 60 грамм грунта

НЬЮ-ЙОРК, 20 октября. /ТАСС/. Космический зонд OSIRIS-REx предпримет во вторник первую попытку забора образца грунта с астероида Бенну, однако о том, насколько успешной окажется эксперимент, станет известно лишь несколько дней спустя. Об этом сообщила в понедельник руководитель программы OSIRIS-REx, представитель аэрокосмической корпорации Lockheed Martin Бет Бак.

"Последний набор команд для зонда проходит проверку и будет направлен на борт в ближайшее время, - сообщила она. - Во вторник около 11 часов утра по времени восточного побережья США (18:00 мск) начнется маневр схода зонда с орбиты вокруг астероида, будет развернута штанга с прибором для забора образца грунта". На этом этапе, пояснила она, солнечные батареи зонда будут развернуты так, чтобы не мешать маневру.

В 18:12 (01:12 мск 21 октября) штанга коснется поверхности астероида в точке "Найтингейл" всего на 16 секунд. В этот момент произойдет выброс из одной из трех находящихся на штанге капсул с азотом, и под воздействием этого газа частицы грунта диаметром около 2 см оторвутся от поверхности и будут втянуты устройство для забора пробы. Сразу после этого зонд начнет маневр ухода от астероида.

Информация о завершении маневра поступит в центр управления во вторник вечером, пояснила она. Однако данные о том, сколько именно грунта удалось забрать, поступят, вероятно, в субботу. Эксперты рассчитывают, что удастся собрать по крайней мере 60 грамм грунта. В случае, если первая попытка забора грунта будет неудачной, вторая попытка будет осуществлена позднее в точке "Оспри". Капсула с собранным грунтом будет доставлена на Землю в 2023 году.

Участок на поверхности астероида Бенну, получивший обозначение "Найтингейл" представляет собой кратер диаметром около 20 метров в северной части астероида. Его дно покрыто мелкими обломками, но у стены кратера есть и несколько крупных глыб, размеры которых превышают 7 метров.
 Скрытый текст:
Станция OSIRIS-REx была запущена в космос в сентябре 2016 года в рамках миссии по сближению с астероидом Бенну (1999 RQ36) и сбору образцов с его поверхности. Она достигла небесного тела в начале декабря 2018 года и осуществила съемку всей поверхности астероида.

Как отметила руководитель департамента планетологических исследований NASA Лори Глейз, "астероид - это своеобразная капсула времени, которая хранит информацию о времени возникновения Солнечной системы". Исследование малых небесных тел, добавила она, "помогут лучше понять процесс формирования планет, а также процесс возникновения и эволюции жизни на Земле".


Цитата NASA's OSIRIS-REx @OSIRISREx 4 мин. назад

I'm GO for orbit departure! Just fired my Attitude Control System (ACS) thrusters and left my safe-home orbit. Nightingale, I'm comin' for ya. #ToBennuAndBack

https://video.twimg.com/ext_tw_video/1318609409250086912/pu/vid/1280x720/MpbSEvQGrmtWxuYX.mp4 (0:07)


ЦитатаSample Asteroid Bennu in 360

 NASA Goddard

16 окт. 2020 г.


https://www.youtube.com/watch?v=KGdooPr8XfI (3:32)


Цитата NASA's OSIRIS-REx @OSIRISREx 8 мин. назад

I'm starting to stretch out the TAGSAM (Touch-And-Go Sample Acquisition Mechanism) arm to sampling position 🦾 this will take about 30 minutes to fully extend. Hang tight!

https://video.twimg.com/ext_tw_video/1318613836174446595/pu/vid/1280x720/B7y3-naPkOs21Rtv.mp4 (0:08)


Цитата NASA's OSIRIS-REx @OSIRISREx 1 мин. назад

T-3:45 to touchdown!

This is my current configuration and location relative to Bennu 🛰


Цитата NASA's OSIRIS-REx @OSIRISREx 4 мин. назад

Alrighty, my TAGSAM arm is fully extended and ready to reach for that sample 🤙 #ToBennuAndBack


Цитата NASA's OSIRIS-REx @OSIRISREx 5 мин. назад

Time to slew! Over the next 10 minutes, I'll slowly rotate to point the navigation cameras toward Bennu. I need a good view of Bennu's landmarks to understand where I am. This navigation technique is called Natural Feature Tracking - learn more here: https://bit.ly/31EqzAE



Цитата20 ОКТ, 21:38
Зонд OSIRIS-REx начал сближение с астероидом Бенну для забора грунта

НЬЮ-ЙОРК, 20 октября. /ТАСС/. Космический зонд OSIRIS-REx начал маневр сближения с астероидом Бенну для забора образца грунта. Как сообщило во вторник в Twitter Национальное управление по аэронавтике и исследованию космического пространства (NASA), "на борту зонда включены маневровые двигатели, он сошел с орбиты вокруг астероида".

Попытка забора грунта в кратере диаметром около 20 метров в северной части астероида будет осуществлена в 18:12 (01:12 мск 21 октября). Штанга с со специальным устройством для забора образца коснется поверхности астероида всего на 16 секунд. В этот момент произойдет выброс из одной из трех находящихся на штанге капсул с азотом, под воздействием этого газа частицы грунта диаметром около 2 см оторвутся от поверхности и будут втянуты устройство для забора пробы.

Эксперты рассчитывают, что удастся собрать по крайней мере 60 грамм грунта.

В случае, если первая попытка забора грунта будет неудачной, позднее будет предпринята вторая. Капсулу с собранным грунтом планируется доставить на Землю в 2023 году.


Цитата NASA's OSIRIS-REx @OSIRISREx 18 мин. назад

Say cheese 📸 just took my first pic of Bennu for NFT navigation guidance. I'll compare it to an onboard image catalog and look for familiar boulders to make sure I'm going in the right direction ↘️ #ToBennuAndBack


Цитата NASA's OSIRIS-REx @OSIRISREx 1 мин. назад

The OSIRIS-REx Thermal Emission Spectrometer (OTES) is powered ON. OTES will collect science data during today's sampling event. The instrument will document site Nightingale's mineral composition and temperature emissions.


Цитата Jonathan McDowell @planet4589 42 мин. назад

So the summary for @OSIRISREx seems to be: orbit departure burn 1732 UTC, checkpoint burn 2131 UTC, Matchpoint burn 2142 UTC, touchdown 2153 UTC, ascent burn 10 seconds later, back-away burn 2224 UTC; the graphic doesn't tell us about the return-to-1km-orbit  burn time.

41 мин. назад

And again, the times the data from these events reaches Earth are all later by 18min 31 seconds


Цитата NASA's OSIRIS-REx @OSIRISREx 11 мин. назад

I'm on my way... slowly but surely. My next major activity isn't for another hour and a half, but in the meantime I'll be taking lots of NFT images to make sure I'm on the right path. Hang tight, I'll keep you updated during my journey iurl=https://twitter.com/hashtag/ToBennuAndBack?src=hashtag_click]#ToBennuAndBack[/iurl]!