OSIRIS-REx

Автор Anatoly Zak, 26.05.2011 08:53:55

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tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 21 авг.

Happy Friday y'all 🤠

The image series on the left was captured during Matchpoint rehearsal. The graphic on the right illustrates the footprint of the images collected by the MapCam and SamCam imagers, and shows where they were taken in relation to site Nightingale.
https://video.twimg.com/tweet_video/Ef9nTWkU0AAADXh.mp4 (0:54)


21 авг.

The orange circle shows Nightingale's location. The blue boxes in the beginning and end of the series illustrate the region where MapCam captured its 1st and 2nd set of images. The red boxes in the middle of the series show where SamCam collected images.

https://bit.ly/2CNKQv

tnt22

ЦитатаOSIRIS-REx Observes an Asteroid in Action

 NASA Video

9 сент. 2020 г.

Using data collected by NASA's OSIRIS-REx mission, this animation shows the trajectories of particles after their emission from asteroid Bennu's surface. The animation emphasizes the four largest particle ejection events detected at Bennu from December 2018 through September 2019. Additional particles, some with lifetimes of several days, that are not related to the ejections are also visible.

 Credits: M. Brozovic/JPL-Caltech/NASA/University of Arizona

youtu.be/lgQxaiZRY-4

https://www.youtube.com/watch?v=lgQxaiZRY-4 (0:43)

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 8 сент.

TAG is TRICKY!... And it's only 6 weeks (42 days) away!

October 20th will be the first time that NASA has ever tried to touch the surface of an asteroid and collect a sample from it.
https://video.twimg.com/amplify_video/1301937458108444672/vid/1280x720/SzQWV4ByYJsEnhhB.mp4 (0:04)


8 сент.

This is also the first time the TAG (Touch-And-Go) technique will be used to collect surface material from a planetary object. This design makes it possible to snag a sample without actually landing on Bennu's surface
https://video.twimg.com/ext_tw_video/1303407139277348864/pu/vid/1280x720/dnsAFD5Zf38UzCQh.mp4 (0:10)

tnt22

https://nauka.tass.ru/nauka/9421871

Цитата10 СЕН, 17:57
OSIRIS-REx проследил за формированием микрометеоритных выбросов на поверхности Бенну

ТАСС, 10 сентября. Микрометеориты, которые откалываются от Бенну, образуются не из-за таяния льда, а в результате падения других объектов на астероид или от нагрева его поверхности. К таким выводам пришли астрономы, статью которых опубликовал научный журнал JGR: Planets.

"Мы думали, что самой большой неожиданностью будет открытие того, что поверхность Бенну усеяна булыжниками. Однако эти выбросы удивили нас еще больше. Мы потратили весь прошлый год на изучение этих форм поверхностной активности астероида, что позволило нам значительно обогатить наши представления о том, как ведут себя подобные малые небесные тела", - рассказал научный руководитель миссии OSIRIS-REx Данте Лауретта.

Зонд OSIRIS-REx успешно вывели в космос в сентябре 2016 года в рамках миссии по сближению и сбору образцов с поверхности астероида Бенну (1999 RQ36). В недавнем прошлом его считали одной из главных угроз для существования жизни на нашей планете. Зонд добрался до астероида в начале декабря 2018 года.

Практически сразу после этого камеры OSIRIS-REx зафиксировали множество ярких точек, которые окружали астероид и двигались в сторону от него. Ученые не могли понять, что эти точки из себя представляют. Впоследствии оказалось, что это множество микрометеоритов и крупных частиц пыли со средним диаметром в 6 см, которые улетают с поверхности Бенну в космос.

Загадки метеоритных дождей

В последующие месяцы работы на орбите астероида камеры OSIRIS-REx зафиксировали более 300 подобных выбросов. Благодаря этому планетологи детально изучили их и сузили список их возможных источников. Для этого ученые просчитали траектории каждого выброса и локализовали те точки на поверхности Бенну, где они возникли.

Сначала планетологи считали, что их причиной могли быть три разных процесса на поверхности астероида - таяние запасов льда в приповерхностных слоях его грунта, удары других метеоритов и растрескивание его пород под действием солнечного излучения.

Фотографии выбросов и их траектории, как пишут Лауретта и его коллеги, исключают первый вариант. Дело в том, что большая часть выбросов произошла в тех областях поверхности Бенну, где температура поверхности была слишком высока для формирования льда.

С другой стороны, ученые нашли на Бенну следы двух других процессов, в том числе булыжники, расколотые под действием солнечного тепла, а также микрократеры, которые оставили недавние падения небольших астероидов. Поэтому Лауретта и его коллеги пока не могут исключить того, что выбросы с поверхности Бенну могут происходить благодаря какому-то из этих двух процессов или им обоим.

Наблюдения за этими выбросами, по словам ученых, уже помогли узнать внутреннее устройство астероида, а также оценить то, как много частиц вырабатывают крупные малые небесные тела, подобные Бенну. Дальнейшее их изучение, как надеются Лауретта и его коллеги, поможет выяснить их точный источник и понять, как эволюционирует облик астероидов из-за этих процессов.

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 10 сент.

Bennu's tiny gravitational field makes predicting my trajectory a tricky business. Small forces like pressure from sunlight change my path in significant ways. Between Bennu's microgravity and other forces, aiming for a "bullseye" on Bennu's surface is a bit *rocky* Точное попадание Подмигивающее лицо





10 сент.

So our @LockheedMartin teammates designed something that'd work better for Bennu's difficult environment - TAGSAM 🦾

TAGSAM is the Touch-And-Go Sample Acquisition Mechanism, and its collector head is the only part of the spacecraft that'll touch Bennu while snagging a sample.
https://video.twimg.com/ext_tw_video/1303814676875063297/pu/vid/1280x720/k4VHkKR__9iaipZP.mp4 (0:08)


10 сент.

Okay... let's be honest. Microgravity is one thing, but Bennu's surface has definitely been another thing to wrangle. I mean... look at it.
https://video.twimg.com/amplify_video/1301973705975709696/vid/1280x720/aKzdteSGXcUt3vi8.mp4 (1:02)


10 сент.

So, next month I'll be navigating into a space that's about 3 parking spaces wide and surrounded by building-sized boulders... talk about tricky
https://video.twimg.com/ext_tw_video/1304156358246268936/pu/vid/1280x720/thqkNwi_fK_yAbEk.mp4 (0:16)


10 сент.

Getting to this point hasn't been easy, and it's required a lot of perseverance and ingenuity from my team! TAG will be another challenging milestone, but we're ready!

tnt22

ЦитатаOSIRIS-REx: Above and Beyond

 NASA Goddard

18 сент. 2020 г.

Since arriving at asteroid Bennu in Dec. 2018, NASA's OSIRIS-REx mission has achieved many feats - from setting a record-breaking orbit, to mapping the asteroid's surface better than any planetary body. The mission is now preparing to collect a sample of Bennu, which will be the first time that NASA has gathered pieces of an asteroid. On Oct. 20, the OSIRIS-REx mission will perform the first attempt of its Touch-And-Go (TAG) sample collection event. Not only will the spacecraft navigate to the surface using innovative navigation techniques, but it could also collect the largest sample since the Apollo missions. The spacecraft will deliver the sample to Earth on Sep. 24, 2023.

youtu.be/O7ZruHLIvR0

https://www.youtube.com/watch?v=O7ZruHLIvR0 (2:27)

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 16 сент.

Asteroid Bennu's orbit made it an ideal target for my team... but every rose has its thorn  Every 6 years, Bennu comes very close to Earth (within 0.002 AU), making its orbit potentially hazardous.
https://video.twimg.com/amplify_video/1306301539842027523/vid/640x360/vWASBUeoxIEcKNy-.mp4 (2:26)

tnt22

ЦитатаMeteorites From Vesta Found on Asteroid Bennu

 NASA Goddard

21 сент. 2020 г.

In an interplanetary faux pas, it appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA's OSIRIS-REx spacecraft. The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu, which is a "rubble pile" asteroid that coalesced from the fragments of a massive collision.

youtu.be/RRDObFMY9ak

https://www.youtube.com/watch?v=RRDObFMY9ak (2:08)

tnt22

https://www.nasa.gov/feature/goddard/2020/bennu-vesta-meteorites

ЦитатаSept. 21, 2020

NASA's OSIRIS-REx to Asteroid Bennu: "You've got a little Vesta on you..."

In an interplanetary faux pas, it appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA's OSIRIS-REx spacecraft. The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu, which is a "rubble pile" asteroid that coalesced from the fragments of a massive collision.

youtu.be/RRDObFMY9ak
It appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA's OSIRIS-REx spacecraft. The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu.
Credits: NASA's Goddard Space Flight Center


"We found six boulders ranging in size from 5 to 14 feet (about 1.5 to 4.3 meters) scattered across Bennu's southern hemisphere and near the equator," said Daniella DellaGiustina of the Lunar & Planetary Laboratory, University of Arizona, Tucson. "These boulders are much brighter than the rest of Bennu and match material from Vesta."


During spring 2019, NASA's OSIRIS-REx spacecraft captured these images, which show fragments of asteroid Vesta present on asteroid Bennu's surface. The bright boulders (circled in the images) are pyroxene-rich material from Vesta. Some bright material appear to be individual rocks (left) while others appear to be clasts within larger boulders (right).
Credits: NASA/Goddard/University of Arizona


"Our leading hypothesis is that Bennu inherited this material from its parent asteroid after a vestoid (a fragment from Vesta) struck the parent," said Hannah Kaplan of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Then, when the parent asteroid was catastrophically disrupted, a portion of its debris accumulated under its own gravity into Bennu, including some of the pyroxene from Vesta."

DellaGiustina and Kaplan are primary authors of a paper on this research appearing in Nature Astronomy September 21.

The unusual boulders on Bennu first caught the team's eye in images from the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) Camera Suite (OCAMS). They appeared extremely bright, with some almost ten times brighter than their surroundings. They analyzed the light from the boulders using the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) instrument to get clues to their composition. A spectrometer separates light into its component colors. Since elements and compounds have distinct, signature patterns of bright and dark across a range of colors, they can be identified using a spectrometer. The signature from the boulders was characteristic of the mineral pyroxene, similar to what is seen on Vesta and the vestoids, smaller asteroids that are fragments blasted from Vesta when it sustained significant asteroid impacts. 

Of course it's possible that the boulders actually formed on Bennu's parent asteroid, but the team thinks this is unlikely based on how pyroxene typically forms. The mineral typically forms when rocky material melts at high-temperature. However, most of Bennu is composed of rocks containing water-bearing minerals, so it (and its parent) couldn't have experienced very high temperatures. Next, the team considered localized heating, perhaps from an impact. An impact needed to melt enough material to create large pyroxene boulders would be so significant that it would have destroyed Bennu's parent-body. So, the team ruled out these scenarios, and instead considered other pyroxene-rich asteroids that might have implanted this material to Bennu or its parent.

Observations reveal it's not unusual for an asteroid to have material from another asteroid splashed across its surface. Examples include dark material on crater walls seen by the Dawn spacecraft at Vesta, a black boulder seen by the Hayabusa spacecraft on Itokawa, and very recently, material from S-type asteroids observed by Hayabusa2 at Ryugu. This indicates many asteroids are participating in a complex orbital dance that sometimes results in cosmic mashups.

As asteroids move through the solar system, their orbits can be altered in many ways, including the pull of gravity from planets and other objects, meteoroid impacts, and even the slight pressure from sunlight. The new result helps pin down the complex journey Bennu and other asteroids have traced through the solar system.

Based on its orbit, several studies indicate Bennu was delivered from the inner region of the Main Asteroid Belt via a well-known gravitational pathway that can take objects from the inner Main Belt to near-Earth orbits. There are two inner Main Belt asteroid families (Polana and Eulalia) that look like Bennu: dark and rich in carbon, making them likely candidates for Bennu's parent. Likewise, the formation of the vestoids is tied to the formation of the Veneneia and Rheasilvia impact basins on Vesta, at roughly about two billion years ago and approximately one billion years ago, respectively.

"Future studies of asteroid families, as well as the origin of Bennu, must reconcile the presence of Vesta-like material as well as the apparent lack of other asteroid types. We look forward to the returned sample, which hopefully contains pieces of these intriguing rock types," said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. "This constraint is even more compelling given the finding of S-type material on asteroid Ryugu. This difference shows the value in studying multiple asteroids across the solar system."

The spacecraft is going to make its first attempt to sample Bennu in October and return it to Earth in 2023 for detailed analysis. The mission team closely examined four potential sample sites on Bennu to determine their safety and science value before making a final selection in December 2019. DellaGiustina and Kaplan's team thinks they might find smaller pieces of Vesta in images from these close-up studies.

The research was funded by the NASA New Frontiers Program. The primary authors acknowledge significant collaboration with the French space agency CNES and Japan Society for the Promotion of Science Core-to-core Program on this paper. NASA's Goddard Space Flight Center in Greenbelt, Maryland 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. The late Michael Drake of the University of Arizona pioneered the study of vestoid meteorites and was the first principal investigator for OSIRIS-REx. 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. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

Last Updated: Sept. 22, 2020
Editor: Bill Steigerwald

tnt22

ЦитатаOSIRIS-REx Meets Bennu's Surprises

 NASA Goddard

23 сент. 2020 г.

The OSIRIS-REx team has already pushed the boundaries of scientific exploration -- going from ground-based radar images from Arecibo in Puerto Rico all the way to orbiting a few hundred meters from asteroid Bennu. The team is mere days away from a sample collection attempt at the asteroid surface. Before this attempt, we take a look back at some of the major achievements, surprises and challenges of sampling an asteroid with OSIRIS-REx.

youtu.be/j_hSNBmpuqY

https://www.youtube.com/watch?v=j_hSNBmpuqY (2:19)

tnt22

https://www.nasa.gov/press-release/nasa-to-provide-update-on-agency-s-first-asteroid-sample-collection-attempt

ЦитатаSept. 22, 2020
MEDIA ADVISORY M20-104

NASA to Provide Update on Agency's First Asteroid Sample Collection Attempt

NASA is hosting a media teleconference at 3 p.m. EDT Thursday, Sept. 24, to provide an update on the agency's first attempt to contact the surface of asteroid Bennu and collect a sample next month. Teleconference audio and visuals will stream live on NASA's website.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft will travel to the asteroid's surface during its first sample collection attempt Oct. 20. Its sampling mechanism will touch Bennu's surface for several seconds, fire a charge of pressurized nitrogen to disturb the surface, and collect a sample before the spacecraft backs away.

Participating in this mission update are:

  • Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate
  • Lori Glaze, director of NASA's Planetary Science Division
  • Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson
  • Mike Moreau, OSIRIS-REx deputy project manager at NASA's Goddard Space Flight Center
  • Sandra Freund, OSIRIS-REx mission operations manager at Lockheed Martin Space

...

In response to rocky conditions discovered on the asteroid's surface when OSIRIS-REx began orbiting Bennu in 2018, the mission team has reduced the sample area to one-tenth of the original plan. This means the spacecraft must target Bennu's surface with even greater accuracy.

A building-size boulder also is situated on Nightingale crater's eastern rim, which could pose a hazard to the spacecraft as it backs away from the asteroid after collecting the sample. The OSIRIS-Rex team performed two rehearsal operations to prepare for these challenges and is ready.

The spacecraft is scheduled to begin the journey back to Earth next year, arriving with the sample in 2023.

Studying Bennu helps researchers learn more about the origins of our solar system, sources of water and organic molecules on Earth, and hazards and resources in near-Earth space. For more information on OSIRIS-Rex, visit:


and


-end-

Last Updated: Sept. 22, 2020
Editor: Sean Potter

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 23 сент.

So ... what does TAG day look like for me?

First, I leave orbit to begin my journey to Bennu's surface, then perform the Checkpoint and Matchpoint burns to steeply descend to the surface, and then... it's sample collection time!
https://video.twimg.com/ext_tw_video/1308516332418207744/pu/vid/1280x720/UVBpTu9-B060xTpi.mp4 (0:07)


23 сент.

Using my TAGSAM arm, I'll touch site Nightingale for several seconds. Once I sense contact with the surface, I'll fire a bottle of nitrogen gas to disturb the ground, and some of that material will be gathered in the sample collector head. Finally putting my arm to use 
https://video.twimg.com/ext_tw_video/1308516777211518976/pu/vid/1280x720/VF2HUzvA_fCldYP4.mp4 (0:07)


23 сент.

My arm has a spring in its "elbow", so when I touchdown on the surface the spring will compress a little (kind of like a pogo stick). This compression is what signals the gas bottle to fire 
https://video.twimg.com/ext_tw_video/1308517321950937088/pu/vid/1280x720/QjY_FoEujGmCgLVy.mp4 (0:10)

tnt22

ЦитатаOSIRIS-REx TAG Trailer

 NASA Goddard

24 сент. 2020 г.

On Oct. 20, the OSIRIS-REx mission will perform the first attempt of its Touch-And-Go (TAG) sample collection event. Not only will the spacecraft navigate to the surface using innovative navigation techniques, but it could also collect the largest sample since the Apollo missions.

youtu.be/vZxGPyh-4_g

https://www.youtube.com/watch?v=vZxGPyh-4_g (1:28)

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 6 ч. назад

Here are my activities for TAG day... download this poster and follow along during the sample collection event on Oct. 20 https://bit.ly/33VYeHd


tnt22

Цитата: undefined NASA's OSIRIS-REx @OSIRISREx 6 ч. назад

Ideally, I'll collect a sample on the 1st try, but there's always a chance I don't. The most likely reason would be if I predict contact with a hazardous area during descent. In that case, I'll put on the brakes and back-away when I'm about 16 ft (5 m) from the surface 
https://video.twimg.com/amplify_video/1309215781138309120/vid/1280x720/GU4Ntwki2ZBW702d.mp4 (0:34)


6 ч. назад

There are other scenarios that could also make it difficult to collect a sufficient sample... like touching down on a boulder or rocks - areas where fine-grained material isn't present. Luckily, I have 3 gas bottles and can always try again if necessary.
https://video.twimg.com/amplify_video/1309216033245294592/vid/1280x720/q4vBafchmsOoFXwB.mp4 (0:41)


6 ч. назад

After the Touch-And-Go (TAG) sample collection event, my team will be able to verify if material was collected by imaging the inside of the sample collector head. I'll also perform a spin maneuver so that my team can calculate the difference in inertia & measure the sample's mass
https://video.twimg.com/ext_tw_video/1309216541846634496/pu/vid/1280x720/SFREcCIKo2QDiWWX.mp4 (0:40)


6 ч. назад

After my two-year journey back to Earth, I'll release the Sample Return Capsule for touch down in the Utah desert. The sample of Bennu will be delivered on Sep. 24, 2023, which is exactly 3 years from today! Happy Sample Return day 
https://video.twimg.com/ext_tw_video/1309216784206028800/pu/vid/1280x720/s_7HpvDwI5NYITm9.mp4 (0:13)

tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 6 ч. назад

At the very end of the TAGSAM arm is the sample collector head - it's sort of like my hand, and it'll be the only part of me that touches Bennu's surface while gathering a sample.

Image details: https://bit.ly/2G5SFhm




6 ч. назад

The collector head is very flexible, and is connected via a hinge-like design so that it can tilt with Bennu's surface. It's also pretty small, measuring 12 inches (30 cm) in diameter - a bit bigger than a dinner plate!
https://video.twimg.com/tweet_video/EjB4MW_U8AAiHZO.mp4 (0:09)


6 ч. назад

Once I touch down and the gas disturbs the surface material, some of those rocks and dust will be gathered into the collector head...
https://video.twimg.com/ext_tw_video/1310680753689116672/pu/vid/1280x720/IvVszzS6hqFuKSgm.mp4 (0:14)


6 ч. назад

My team won't know whether I've successfully collected a sample until a couple of days after TAG. But once I take images of inside the sampler head, we'll know what we've got! Then I'll be able to show you the sample that Earth scientists will study for generations to come 
https://video.twimg.com/ext_tw_video/1310681501546156032/pu/vid/1280x720/WHm314UR764xV20d.mp4 (0:16)

tnt22

08.10.2020 23:44:58 #696 Последнее редактирование: 09.10.2020 00:02:59 от tnt22
https://www.asteroidmission.org/?latest-news=nasas-osiris-rex-unlocks-more-secrets-from-asteroid-bennu

Цитата
NASA's OSIRIS-REx Unlocks More Secrets from Asteroid Bennu

October 8, 2020 - NASA's first asteroid sample return mission now knows much more about the material it'll be collecting in just a few weeks. In a special collection of six papers published today in the journals Science and Science Advances, scientists on the OSIRIS-REx mission present new findings on asteroid Bennu's surface material, geological characteristics, and dynamic history. They also suspect that the delivered sample of Bennu may be unlike anything we have in the meteorite collection on Earth.


NASA's OSIRIS-REx mission created these images using false-color Red-Green-Blue (RGB) composites of asteroid Bennu. A 2D map and spacecraft imagery were overlaid on a shape model of the asteroid to create these false-color composites. In these composites, spectrally average and bluer than average terrain looks blue, surfaces that are redder than average appear red. Bright green areas correspond to the instances of a mineral pyroxene, which likely came from a different asteroid, Vesta. Black areas near the poles indicate no data. Credit: NASA/Goddard/University of Arizona

These discoveries complete the OSIRIS-REx mission's pre-sample collection science requirements and offer insight into the sample of Bennu that scientists will study for generations to come.

One of the papers, led by Amy Simon from NASA's Goddard Space Flight Center in Greenbelt, Maryland, shows that carbon-bearing, organic material is widespread on the asteroid's surface, including at the mission's primary sample site, Nightingale, where OSIRIS-REx will make its first sample collection attempt on October 20. These findings indicate that hydrated minerals and organic material will likely be present in the collected sample.

This organic matter may contain carbon in a form often found in biology or in compounds associated with biology. Scientists are planning detailed experiments on these organic molecules and expect that the returned sample will help answer complex questions about the origins of water and life on Earth.

"The abundance of carbon-bearing material is a major scientific triumph for the mission. We are now optimistic that we will collect and return a sample with organic material - a central goal of the OSIRIS-REx mission," said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson.

Authors of the special collection have also determined that carbonate minerals make up some of the asteroid's geological features. Carbonate minerals often precipitate from hydrothermal systems that contain both water and carbon dioxide. A number of Bennu's boulders have bright veins that appear to be made of carbonate - some of which are located near the Nightingale crater, meaning that carbonates might be present in the returned sample.

The study of the carbonates found on Bennu was led by Hannah Kaplan, from Goddard. These findings have allowed scientists to theorize that Bennu's parent asteroid likely had an extensive hydrothermal system, where water interacted with and altered the rock on Bennu's parent body. Although the parent body was destroyed long ago, we're seeing evidence of what that watery asteroid once looked like here - in its remaining fragments that make up Bennu. Some of these carbonate veins in Bennu's boulders measure up to a few feet long and several inches thick, validating that an asteroid-scale hydrothermal system of water was present on Bennu's parent body.


During fall 2019, NASA's OSIRIS-REx spacecraft captured this image, which shows one of asteroid Bennu's boulders with a bright vein that appears to be made of carbonate. The image within the circle (lower right) shows a focused view of the vein. Credit: NASA/Goddard/University of Arizona

Scientists made another striking discovery at site Nightingale: its regolith has only recently been exposed to the harsh space environment, meaning that the mission will collect and return some of the most pristine material on the asteroid. Nightingale is part of a population of young, spectrally red craters identified in a study led by Dani DellaGiustina at the University of Arizona. Bennu's "colors" (variations in the slope of the visible-wavelength spectrum) are much more diverse than originally anticipated. This diversity results from a combination of different materials inherited from Bennu's parent body and different durations of exposure to the space environment.

This paper's findings are a major milestone in an ongoing debate in the planetary science community - how primitive asteroids like Bennu change spectrally as they are exposed to "space weathering" processes, such as bombardment by cosmic rays and solar wind. While Bennu appears quite black to the naked eye, the authors illustrate the diversity of Bennu's surface by using false-color renderings of multispectral data collected by the MapCam camera. The freshest material on Bennu, such as that found at the Nightingale site, is spectrally redder than average and thus appears red in these images. Surface material turns vivid blue when it has been exposed to space weathering for an intermediate period of time. As the surface material continues to weather over long periods of time, it ultimately brightens across all wavelengths, becoming a less intense blue - the average spectral color of Bennu.

The paper by DellaGiustina et al. also distinguishes two main types of boulders on Bennu's surface: dark and rough, and (less commonly) bright and smooth. The different types may have formed at different depths in the parent asteroid of Bennu.

Not only do the boulder types differ visually, they also have their own unique physical properties. The paper led by Ben Rozitis from The Open University in the UK shows that the dark boulders are weaker and more porous, whereas the bright boulders are stronger and less porous. The bright boulders also host the carbonates identified by Kaplan and crew, suggesting that the precipitation of carbonate minerals in cracks and pore spaces may be responsible for their increased strength.

However, both boulder types are weaker than scientists expected. Rozitis and colleagues suspect that Bennu's dark boulders (the weaker, more porous, and more common type) would not survive the journey through Earth's atmosphere. It's therefore likely that the returned samples of asteroid Bennu will provide a missing link for scientists, as this type of material is not currently represented in meteorite collections.

Bennu is a diamond-shaped pile of rubble floating in space, but there's more to it than meets the eye. Data obtained by the OSIRIS-REx Laser Altimeter (OLA) - a science instrument contributed by the Canadian Space Agency - have allowed the mission team to develop a 3D digital terrain model of the asteroid that, at 20 cm resolution, is unprecedented in detail and accuracy. In this paper, led by Michael Daly of York University, scientists explain how detailed analysis of the asteroid's shape revealed ridge-like mounds on Bennu that extend from pole-to-pole, but are subtle enough that they could be easily missed by the human eye. Their presence has been hinted at before, but their full pole-to-pole extents only became clear when the northern and southern hemispheres were split apart in the OLA data for comparison.

The digital terrain model also shows that Bennu's northern and southern hemispheres have different shapes. The southern hemisphere appears to be smoother and rounder, which the scientists believe is a result of loose material getting trapped by the region's numerous large boulders.

Another paper in the special collection, led by Daniel Scheeres of University of Colorado Boulder, examines the gravity field of Bennu, which has been determined by tracking the trajectories of the OSIRIS-REx spacecraft and the particles that are naturally ejected from Bennu's surface. The use of particles as gravity probes is fortuitous. Prior to the discovery of particle ejection on Bennu in 2019, the team was concerned about mapping the gravity field to the required precision using only spacecraft tracking data. The natural supply of dozens of mini gravity probes allowed the team to vastly exceed their requirements and gain unprecedented insight into the asteroid interior.

The reconstructed gravity field shows that the interior of Bennu is not uniform. Instead, there are pockets of higher and lower density material inside the asteroid. It's as if there is a void at its center, within which you could fit a couple of football fields. In addition, the bulge at Bennu's equator is under-dense, suggesting that Bennu's rotation is lofting this material.

All six publications in the special collection use global and local datasets collected by the OSIRIS-REx spacecraft from Feb. through Oct. 2019. The special collection underscores that sample return missions like OSIRIS-REx are essential to fully understanding the history and evolution of our Solar System.

The mission is less than two weeks away from fulfilling its biggest goal - collecting a piece of a pristine, hydrated, carbon-rich asteroid. OSIRIS-REx will depart Bennu in 2021 and deliver the sample to Earth on Sep. 24, 2023.

NASA's Goddard Space Flight Center in Greenbelt, Maryland, 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 provides 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.

tnt22

08.10.2020 23:58:55 #697 Последнее редактирование: 09.10.2020 00:07:35 от tnt22
https://nauka.tass.ru/nauka/9668903

Цитата8 ОКТ, 21:00
На астероиде Бенну нашли следы потоков воды
Об этом говорят залежи карбонатов, которые ученые разглядели на поверхности астероида

ТАСС, 8 октября. Американская межпланетная станция OSIRIS-REx составила полную карту поверхности астероида Бенну и обнаружила в кратере Найтингейл, где произойдет посадка этого аппарата в конце октября, залежи минералов, возникших в результате течения потоков воды. Результаты наблюдений с зонда были опубликованы в серии статей в журналах Science (123 и Science Advances (123).

"Анализируя фотографии зоны посадки OSIRIS-REx, мы заметили в кратере Найтингейл целую сеть из тонких прожилок, которые заполнены яркими минералами. Мы предполагаем, что это залежи карбонатов, аналогичные тем, которые встречаются в хондритах (один из наиболее распространенных типов метеоритов, - прим. ТАСС), которые подверглись воздействию воды. Если это действительно так, то это означает, что на протяжении многих тысяч или даже миллионов лет по поверхности прародителя Бенну текли потоки жидкой воды", - пишут исследователи.

Бенну - это небольшой (его диаметр около 600 м) околоземной астероид, который открыли в 2013 году. Для исследования этого объекта в сентября 2016 года NASA запустило к нему межпланетную станцию OSIRIS-REx. На орбиту астероида станция вышла 31 декабря 2018 года.

Первые наблюдения показали, что поверхность Бенну усеяна крупными булыжниками, а в его породах содержится много воды. Это сделало астероид особенно интересным для изучения с точки зрения того, как формировалась Солнечная система.

Следующие месяцы и годы научная команда миссии потратила на выбор места для посадки зонда и на составление детальной геологической, минеральной и топографической карты астероида. Это принесло множество неожиданностей и новых открытий, которые прояснили историю формирования Бенну.

Новые тайны "астероида судного дня"

В частности, ученые нашли множество различий в структуре и окраске многих областей астероида и усеивающих его булыжников. Это говорит о том, считают планетологи, что поверхность астероида менялась очень сложным образом, постоянно обновляясь, при этом космическая эрозия по-разному воздействовала на породы Бенну.

Трехмерная модель и карта высоты поверхности астероида указывают на то, что форма, облик и размеры его северного и южного полушарий неодинаковы. В частности, южное полушарие астероида оказалось более гладким и шарообразным, а на поверхности северной половины Бенну крупных булыжников значительно больше.

Исследователи считают, что эти различия возникли в первые мгновения существования Бенну. Они показывают, как астероид формировался, а потом раскололся на несколько частей, которые впоследствии, впрочем, соединились друг с другом. В пользу этого говорят и гравиметрические наблюдения, согласно которым пустоты в недрах астероида распределяются очень неравномерно: их много в районе экватора и практически нет в приполярных регионах.

Интересно, что замеры температуры отдельных булыжников, а также скорости их охлаждения ночью указывают на то, что поверхность Бенну покрыта двумя разными типами подобных структур. Ученые пока не нашли причин этого явления. В частности, это может говорить о кардинально разных условиях их формирования в первые эпохи существования Солнечной системы.

Самое важное геологическое открытие OSIRIS-REx заключается в том, что инструменты зонда нашли множество залежей карбонатов и других осадочных горных пород, которые формируются только в присутствии жидкой воды, а также прослойку из сложной органики, которая покрывает булыжники и многие части поверхности Бенну. Посадка зонда в кратере Найтингейл, как отмечают исследователи, даст человечеству первую возможность изучить их состав.

Забрав грунт (это должно произойти в конце октября этого года), OSIRIS-REx запустит капсулу с ним в сторону Земли. Если все пройдет удачно, она упадет на территории штата Юта в конце сентября 2023 года. Анализ грунта позволит ученым перепроверить полученные выводы и узнать важнейшие детали первых дней существования Солнца и окружающих его планет.

Snowsquall

10.10.2020 09:13:03 #698 Последнее редактирование: 10.10.2020 09:15:47 от Snowsquall
Автоматическая станция OSIRIS-REx 20 октября 2020 года попытается забрать 60 гр грунта с поверхности потенциально опасного астероида Бенну.

Подробности о процессе забора образцов грунта


tnt22

Цитата NASA's OSIRIS-REx @OSIRISREx 15 окт.

All right. Time to get in the zone... On TAG day I need to collect at least 2 oz (60 grams) of Bennu's surface material, but there's a chance I could collect up to 4.4 lbs (2 kg) 😱 guess we'll have to wait and see... it's all part of the journey #ToBennuAndBack




16 ч. назад

A few days after TAG I'll perform a pretty slick spin maneuver to figure out how much material I actually collected during the sampling event Жест «позвони мне» I performed the "empty" SMM on Saturday.

https://video.twimg.com/tweet_video/EkZKo8oXkAATZgu.mp4 (0:06)