Автор Anatoly Zak, 26.05.2011 08:53:55
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Цитата: undefinedJune 9, 2020NASA's OSIRIS-REx Discovers Sunlight Can Crack Rocks on Asteroid BennuAsteroids don't just sit there doing nothing as they orbit the Sun. They get bombarded by meteoroids, blasted by space radiation, and now, for the first time, scientists are seeing evidence that even a little sunshine can wear them down.Rocks on asteroid Bennu appear to be cracking as sunlight heats them up during the day and they cool down at night, according to images from NASA's OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security - Regolith Explorer) spacecraft."This is the first time evidence for this process, called thermal fracturing, has been definitively observed on an object without an atmosphere," said Jamie Molaro of the Planetary Science Institute, Tucson, Arizona, lead author of a paper appearing in Nature Communications June 9. "It is one piece of a puzzle that tells us what the surface used to be like, and what it will be like millions of years from now."Examples of disaggregation (top) and linear fractures (bottom) in boulders on asteroid Bennu from images taken by NASA's OSIRIS-REX spacecraft. In the bottom row, fracture orientations are (d) west-northwest to east-southeast and (e, f) north to south.Credits: NASA/Goddard/University of ArizonaDownload unannotated version"Like any weathering process, thermal fracturing causes the evolution of boulders and planetary surfaces over time - from changing the shape and size of individual boulders, to producing pebbles or fine-grained regolith, to breaking down crater walls," said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. "How quickly this occurs relative to other weathering processes tells us how and how quickly the surface has changed."Rocks expand when sunlight heats them during the day and contract as they cool down at night, causing stress that forms cracks that grow slowly over time. Scientists have thought for a while that thermal fracturing could be an important weathering process on airless objects like asteroids because many experience extreme temperature differences between day and night, compounding the stress. For example, daytime highs on Bennu can reach almost 127 degrees Celsius or about 260 degrees Fahrenheit, and nighttime lows plummet to about minus 73 degrees Celsius or nearly minus 100 degrees Fahrenheit. However, many of the telltale features of thermal fracturing are small, and before OSIRIS-REx got close to Bennu, the high-resolution imagery required to confirm thermal fracturing on asteroids didn't exist.The mission team found features consistent with thermal fracturing using the spacecraft's OSIRIS-REx Camera Suite (OCAMS), which can see features on Bennu smaller than one centimeter (almost 0.4 inches). It found evidence of exfoliation, where thermal fracturing likely caused small, thin layers (1 - 10 centimeters) to flake off of boulder surfaces. The spacecraft also produced images of cracks running through boulders in a north-south direction, along the line of stress that would be produced by thermal fracturing on Bennu.Exfoliation features on a cliff face (a) and on boulders (b-f) with varying size and location on asteroid Bennu from images taken by NASA's OSIRIS-REX spacecraft. The bright dome on the horizon of panel (a) is a boulder behind the exfoliating cliff.Credits: NASA/Goddard/University of ArizonaDownload unannotated versionOther weathering processes can produce similar features, but the team's analysis ruled them out. For example, rain and chemical activity can produce exfoliation, but Bennu has no atmosphere to produce rain. Rocks squeezed by tectonic activity can also exfoliate, but Bennu is too small for such activity. Meteoroid impacts do occur on Bennu and can certainly crack rocks, but they would not cause the even erosion of layers from boulder surfaces that were seen. Also, there's no sign of impact craters where the exfoliation is occurring.Additional studies of Bennu could help determine how rapidly thermal fracturing is wearing down the asteroid, and how it compares to other weathering processes. "We don't have good constraints yet on breakdown rates from thermal fracturing, but we can get them now that we can actually observe it for the first time in situ," said OSIRIS-REx project scientist Jason Dworkin of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Laboratory measurements on the properties of the samples returned by the spacecraft in 2023 will help us learn more about how this process works."Another area of research is how thermal fracturing affects our ability to estimate the age of surfaces. In general, the more weathered a surface is, the older it is. For example, a region with a lot of craters is likely to be older than an area with few craters, assuming impacts happen at a relatively constant rate across an object. However, additional weathering from thermal fracturing could complicate an age estimate, because thermal fracturing is going to happen at a different rate on different bodies, depending on things like their distance from the Sun, the length of their day, and the composition, structure and strength of their rocks. On bodies where thermal fracturing is efficient, then it may cause crater walls to break down and erode faster. This would make the surface look older according the cratering record, when in fact it is actually younger. Or the opposite could occur. More research on thermal fracturing on different bodies is needed to start to get a handle on this, according to Molaro.The research was funded by NASA's OSIRIS-REx Participating Scientist program as well as the OSIRIS-REx mission. 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 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: June 9, 2020Editor: Bill Steigerwald
ЦитатаNASA's OSIRIS-REx Is One Rehearsal Away from Touching Asteroid BennuAugust 6, 2020 -NASA's first asteroid sampling spacecraft is making final preparations to grab a sample from asteroid Bennu's surface. Next week, the OSIRIS-REx mission will conduct a second rehearsal of its touchdown sequence, practicing the sample collection activities one last time before touching down on Bennu this fall.This artist's concept shows the trajectory and configuration of NASA's OSIRIS-REx spacecraft during Matchpoint rehearsal, which is the final time the mission will practice the initial steps of the sample collection sequence before touching down on asteroid Bennu. Credit: NASA/Goddard/University of ArizonaOn Aug. 11, the mission will perform its "Matchpoint" rehearsal - the second practice run of the Touch-and-Go (TAG) sample collection event. The rehearsal will be similar to the Apr. 14 "Checkpoint" rehearsal, which practiced the first two maneuvers of the descent, but this time the spacecraft will add a third maneuver, called the Matchpoint burn, and fly even closer to sample site Nightingale - reaching an altitude of approximately 131 ft (40 m) - before backing away from the asteroid.This second rehearsal will be the first time the spacecraft executes the Matchpoint maneuver to then fly in tandem with Bennu's rotation. The rehearsal also gives the team a chance to become more familiar navigating the spacecraft through all of the descent maneuvers, while verifying that the spacecraft's imaging, navigation and ranging systems operate as expected during the event.During the descent, the spacecraft fires its thrusters three separate times to make its way down to the asteroid's surface. The spacecraft will travel at an average speed of around 0.2 mph (0.3 kph) during the approximately four-hour excursion. Matchpoint rehearsal begins with OSIRIS-REx firing its thrusters to leave its 0.5-mile (870-m) safe-home orbit. The spacecraft then extends its robotic sampling arm - the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) - from its folded, parked position out to the sample collection configuration. Immediately following, the spacecraft rotates to begin collecting navigation images for the Natural Feature Tracking (NFT) guidance system. NFT allows OSIRIS-REx to autonomously navigate to Bennu's surface by comparing an onboard image catalog with the real-time navigation images taken during descent. As the spacecraft approaches the surface, the NFT system updates the spacecraft's predicted point of contact depending on OSIRIS-REx's position in relation to Bennu's landmarks.The spacecraft's two solar panels then move into a "Y-wing" configuration that safely positions them up and away from the asteroid's surface. This configuration also places the spacecraft's center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu's surface during the sample collection event.When OSIRIS-REx reaches an altitude of approximately 410 ft (125 m), it performs the Checkpoint burn and descends more steeply toward Bennu's surface for another eight minutes. At approximately 164 ft (50 m) above the asteroid, the spacecraft fires its thrusters a third time for the Matchpoint burn. This maneuver slows the spacecraft's rate of descent and adjusts its trajectory to match Bennu's rotation as the spacecraft makes final corrections to target the touchdown spot. OSIRIS-REx will continue capturing images of Bennu's landmarks for the NFT system to update the spacecraft's trajectory for another three minutes of descent. This brings OSIRIS-REx to its targeted destination around 131 ft (40 m) from Bennu - the closest it has ever been to the asteroid. With the rehearsal complete, the spacecraft executes a back-away burn, returns its solar panels to their original position and reconfigures the TAGSAM arm back to the parked position.During the rehearsal, the one-way light time for signals to travel between Earth and the spacecraft will be approximately 16 minutes, which prevents the live commanding of flight activities from the ground. So prior to the rehearsal's start, the OSIRIS-REx team will uplink all of the event's commands to the spacecraft, allowing OSIRIS-REx to perform the rehearsal sequence autonomously after the GO command is given. Also during the event, the spacecraft's low gain antenna will be its only antenna pointing toward Earth, transmitting data at the very slow rate of 40 bits per second. So while the OSIRIS-REx team will be able to monitor the spacecraft's vital signs, the images and science data collected during the event won't be downlinked until the rehearsal is complete. The team will experience these same circumstances during the actual TAG event in October.Following Matchpoint rehearsal, the OSIRIS-REx team will verify the flight system's performance during the descent, including that the Matchpoint burn accurately adjusted the spacecraft's descent trajectory for its touchdown on Bennu. Once the mission team determines that OSIRIS-REx operated as expected, they will command the spacecraft to return to its safe-home orbit around Bennu.The mission team has spent the last several months preparing for the Matchpoint rehearsal while maximizing remote work as part of its COVID-19 response. On the day of rehearsal, a limited number of personnel will monitor the spacecraft from Lockheed Martin Space's facility, taking appropriate safety precautions, while the rest of the team performs their roles remotely. The mission implemented a similar protocol during the Checkpoint rehearsal in April.On Oct. 20, the spacecraft will travel all the way to the asteroid's surface during its first sample collection attempt. During this event, OSIRIS-REx's sampling mechanism will touch Bennu's surface for approximately five seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 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 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.
Цитата NASA's OSIRIS-REx @OSIRISREx 21 ч. назадTune in tomorrow at 2:30 pm EDT to follow along with the Matchpoint rehearsal activities! Here's what we'll be doing ￼Download the Matchpoint rehearsal poster here: https://bit.ly/3abvwoB
Цитата NASA's OSIRIS-REx @OSIRISREx 16 мин. назадThis is a 4-hour event, and I'm moving at an average speed of approximately 0.2 mph (0.3 kph) relative to Bennu (about the speed of a tortoise). I'll provide updates as each event of the rehearsal sequence occurs.
Цитата NASA's OSIRIS-REx @OSIRISREx 2 мин. назадMy team just received confirmation that I fired my Attitude Control System (ACS) thrusters and left my safe-home orbit. Bennu, here we come.
Цитата NASA's OSIRIS-REx @OSIRISREx 2 мин. назадAlright, time to stretch out the TAGSAM (Touch-and-Go Sample Acquisition Mechanism) arm to sampling position this'll take about 30 minutes to complete - no need to hurry!https://video.twimg.com/tweet_video/EfKTTDeWAAMpSOj.mp4 (0:08)
Цитата NASA's OSIRIS-REx @OSIRISREx 1 ч. назадThe TAGSAM arm is now fully extended
Цитата NASA's OSIRIS-REx @OSIRISREx 1 ч. назадIt's slew time! Over the next 12 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 Natural Feature Tracking (NFT) -- learn more here: https://bit.ly/31EqzAE1 ч. назад
Цитата: undefined NASA's OSIRIS-REx @OSIRISREx 1 ч. назадClick click just took my first pic for NFT navigation guidance. I'll compare it to an onboard image catalog and look for familiar boulder landmarks to make sure I'm going in the right direction
Цитата NASA's OSIRIS-REx @OSIRISREx 37 мин. назадThe OSIRIS-REx Thermal Emission Spectrometer (OTES) is powered ON. OTES will collect science data during the actual sampling event. Today it's scanning the surface so the team can confirm that the instrument completes the exercise as expected.28 мин. назадT-2:00 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!
Цитата NASA's OSIRIS-REx @OSIRISREx 13 мин. назадFor the next 10 minutes, I'll focus on moving my solar panels into the Y-wing configuration. This safely positions the panels up and away from the asteroid's surface.11 мин. назадThe OSIRIS-REx Camera Suite (OCAMS) is powered ON. The camera suite's main goal is to document the sample collection activities. Imagine you're looking at Bennu's surface as you approach the asteroid and then back-away from it - that's what the images will show.7 мин. назадWe are now in the Y-wing configuration
Цитата NASA's OSIRIS-REx @OSIRISREx 5 мин. назадInitiating Checkpoint burn Fire ACS thrusters for 66 seconds 5 мин. назадCheckpoint burn complete For the next 8 minutes, I'll descend more steeply toward Bennu's surface... then it'll be time for the Matchpoint burn!
Цитата NASA's OSIRIS-REx @OSIRISREx 3 мин. назадI just passed 213 ft (65 m) in altitude - this is now the closest I've ever been to Bennu's surface. (I previously reached 213 feet (65 m) during Checkpoint rehearsal in April.) 3 мин. назадInitiating Matchpoint burn Fire ACS thrusters for 10 seconds 3 мин. назадThe Matchpoint burn is complete 3 мин. назадI've arrived at my destination, approx. 131 ft (40 m) over the surface! Time to initiate the back-away burn Next time, I'll keep going until I touch Bennu's surface and collect a sample. Feeling ready for the real deal! #TAGTime
Цитата NASA's OSIRIS-REx @OSIRISREx 1 мин. назадOCAMS, OTES, and the navigation cameras should now be powered OFF. In a bit, I'll put the TAGSAM arm back in its parked position
Цитата NASA's OSIRIS-REx @OSIRISREx 23 мин. назадBack-away burn complete 21 мин. назадPreliminary data show that today's rehearsal went as planned More details to come once all the data from the event are downlinked to Earth. Thanks, everybody, for following along!Next stop: Touchdown on Oct. 20!
ЦитатаOSIRIS-REx Cruises Over Site Nightingale During Final Dress RehearsalCaptured on Aug. 11 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.These images were captured over a 13.5-minute period. The imaging sequence begins at approximately 420 feet (128 meters) above the surface - before the spacecraft executes the "Checkpoint" maneuver - and runs through to the "Matchpoint" maneuver, with the last image taken approximately 144 feet (44 meters) above the surface of Bennu.The spacecraft's sampling arm - called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) - is visible in the lower part of the frame. The round head at the end of TAGSAM is the only part of OSIRIS-REx that will make contact with the surface during the sample collection event. At the end of the gif, a relatively clear, dark patch of Bennu's sample site Nightingale comes into view at the top of the frame. The large, boulder that the spacecraft approaches near the end of the sequence (on the crater's rim) is 43 feet (13 meters) on its longest axis. The gif was created using 42 images taken by the spacecraft's SamCam camera. For context, the images are oriented with Bennu's west at the top.During the sample collection event, which is scheduled for Oct. 20, SamCam will continuously document the entire sampling event and touchdown maneuver.Date Taken: August 11, 2020Instrument Used: OCAMS (SamCam)Credit: NASA/Goddard/University of Arizona
ЦитатаAug. 12, 2020A Successful Second Rehearsal Puts NASA's OSIRIS-REx on a Path to Sample CollectionYesterday, the OSIRIS-REx spacecraft performed its final practice run of the sampling sequence, reaching an approximate altitude of 131 feet (40 meters) over sample site Nightingale before executing a back-away burn. Nightingale, OSIRIS-REx's primary sample collection site, is located within a crater in Bennu's northern hemisphere.The approximately four-hour "Matchpoint" rehearsal took the spacecraft through the first three of the sampling sequence's four maneuvers: the orbit departure burn, the "Checkpoint" burn and the Matchpoint burn. Checkpoint is the point where the spacecraft autonomously checks its position and velocity before adjusting its trajectory down toward the event's third maneuver. Matchpoint is the moment when the spacecraft matches Bennu's rotation in order to fly in tandem with the asteroid surface, directly above the sample site, before touching down on the targeted spot.Four hours after departing its 0.6-mile (1-km) safe-home orbit, OSIRIS-REx performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu's surface. From there, the spacecraft continued to descend for another eight minutes to perform the Matchpoint burn. After descending on this new trajectory for another three minutes, the spacecraft reached an altitude of approximately 131 ft (40 m) - the closest the spacecraft has ever been to Bennu - and then performed a back-away burn to complete the rehearsal.https://www.youtube.com/watch?v=Ak1qjV3YbWYThese images were captured over a 13.5-minute period. The imaging sequence begins at approximately 420 feet (128 meters) above the surface - before the spacecraft executes the "Checkpoint" maneuver - and runs through to the "Matchpoint" maneuver, with the last image taken approximately 144 feet (44 meters) above the surface of Bennu. The spacecraft's sampling arm - called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) - is visible in the lower part of the frame.Credits: NASA/Goddard/University of ArizonaDuring the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft's instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event. These images and science data were downlinked to Earth after the event's conclusion.Because the spacecraft and Bennu are currently about 179 million miles (288 million km) from Earth, it takes approximately 16 minutes for the spacecraft to receive the radio signals used to command it. This time lag prevented live commanding of flight activities from the ground during the rehearsal. As a result, the spacecraft performed the entire rehearsal sequence autonomously. Prior to the rehearsal's start, the OSIRIS-REx team uplinked all of the event's commands to the spacecraft and then provided the "Go" command to begin the event. The actual sample collection event in October will be conducted the same way.This second rehearsal provided the mission team with practice navigating the spacecraft through the first three maneuvers of the sampling event and with an opportunity to verify that the spacecraft's imaging, navigation and ranging systems operated as expected during the first part of the descent sequence.Matchpoint rehearsal also confirmed that OSIRIS-REx's Natural Feature Tracking (NFT) guidance system accurately estimated the spacecraft's trajectory after the Matchpoint burn, which is the final maneuver before the sample collection head contacts Bennu's surface. This rehearsal was also the first time that the spacecraft's on-board hazard map was employed. The hazard map delineates areas that could potentially harm the spacecraft. If the spacecraft detects that it is on course to touch a hazardous area, it will autonomously back-away once it reaches an altitude of 16 ft (5 m). While OSIRIS-REx did not fly that low during the rehearsal, it did employ the hazard map to assess whether its predicted touchdown trajectory would have avoided surface hazards, and found that the spacecraft's path during the rehearsal would have allowed for a safe touchdown on sample site Nightingale.During the last minutes of the spacecraft's descent, OSIRIS-REx also collected new, high-resolution navigation images for the NFT guidance system. These detailed images of Bennu's landmarks will be used for the sampling event, and will allow the spacecraft to accurately target a very small area. "Many important systems were exercised during this rehearsal - from communications, spacecraft thrusters, and most importantly, the onboard Natural Feature Tracking guidance system and hazard map," said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. "Now that we've completed this milestone, we are confident in finalizing the procedures for the TAG event. This rehearsal confirmed that the team and all of the spacecraft's systems are ready to collect a sample in October."The mission team has spent the last several months preparing for Matchpoint rehearsal while maximizing remote work as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel monitored the spacecraft's telemetry from Lockheed Martin Space's facility, NASA's Goddard Space Flight Center and the University of Arizona, taking appropriate safety precautions, while the rest of the team performed their roles remotely.The spacecraft will travel all the way to the asteroid's surface during its first sample collection attempt, scheduled for Oct. 20. During this event, OSIRIS-REx's 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. The spacecraft is scheduled to return the sample to Earth on Sept. 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.by: Brittany EnosUniversity of ArizonaLast Updated: Aug. 12, 2020Editor: Karl Hille
Цитата13 АВГ, 17:25Зонд OSIRIS-REx отрепетировал посадку на астероид БеннуПрогон прошел успешноТАСС, 13 августа. Космический аппарат OSIRIS-REx успешно сблизился с астероидом Бенну на расстояние в 40 метров для того, чтобы проверить все системы перед забором грунта с этого небесного тела. В конце октября 2020 года он должен будет совершить посадку в области "Найтингейл" астероида, чтобы собрать пробы грунта и отправить их впоследствии на Землю. Об этом Центр космических полетов NASA имени Годдарда пишет на своем сайте."Во время этой репетиции мы проверили работу многих важных систем, начиная с систем связи и двигателей и заканчивая навигационными алгоритмами и картами опасности. Испытание прошло успешно: оно подтвердило, что и мы, и OSIRIS-REx готовы к забору грунта в октябре этого года", - рассказал руководитель миссии Данте Лауретта.Во время этой репетиции, которая повторяла весь процесс посадки на Бенну, OSIRIS-REx сблизился с астероидом в полностью автоматическом режиме. При этом он опустился на высоту в 40 метров от поверхности небесного тела, и провел серию маневров, которые нужны для сбора грунта и взлета с астероида.В частности, аппарат успешно развернул манипулятор TAGSAM, которая будет захватывать грунт с поверхности Бенну, а также протестировал научные инструменты и автономную навигационную систему, которая будет помогать ему избегать столкновений с булыжниками, усеивающими поверхность астероида.Все инструменты и системы зонда, как отметил Лауретта, отработали идеально. Как надеются ученые, столь же успешно пройдет реальная посадка на поверхность Бенну. Она намечена на 20 октября текущего года.Астероид Судного дня Скрытый текст: 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 достиг небесного тела в начале декабря 2018 года.Данные OSIRIS-REx показали, что по форме и окраске Бенну очень похож на другой астероид - Рюгу, который аппарат "Хаябуса-2" изучал на протяжении последних полутора лет. В отличие от сухого и безводного Рюгу в породах Бенну оказалось рекордное количество воды. Это сделало его еще более интересным для астрономов объектом.После забора грунта OSIRIS-REx запустит капсулу с ним в сторону Земли. Если все пройдет удачно, она упадет на территории штата Юта в конце сентября 2023 года.
Цитата NASA's OSIRIS-REx @OSIRISREx 18 авг.Another incredible view from last week's Matchpoint rehearsal!This image series shows the navigation camera's perspective during the event, as well as my closest approach of ~131 feet (~40 meters). Near the end, site Nightingale comes into view at the top of the frame.https://video.twimg.com/amplify_video/1295755794986627073/vid/960x720/rEG50Z2wvnO_gyKW.mp4 (0:39)18 авг.The series was taken by NavCam 2 over a 3-hour period - beginning ~1 hour after the orbit departure maneuver and ending ~2 minutes after the back-away burn. NavCam 2 captures images for the spacecraft's Natural Feature Tracking (NFT) navigation system.
ЦитатаMatchpoint Rehearsal from the Lens of MapCamCaptured on Aug. 11 during the second rehearsal of the OSIRIS-REx mission's sample collection event, this series of images shows the MapCam imager's field of view as the NASA spacecraft approaches and moves away from 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.These images were captured over a two-minute period. The imaging sequence begins at approximately 144 feet (44 meters) above the surface - three minutes after the spacecraft executed the "Matchpoint" maneuver - and ends approximately two minutes after the back-away maneuver, with the last image taken approximately 200 feet (61 meters) above the surface of Bennu. This image series also captures the spacecraft's closest approach, with the nearest image taken approximately 135 feet (41 meters) from the asteroid's surface. The gif was created using 22 images taken by the spacecraft's MapCam camera.For reference, the image series shows the central region of the crater where sample site Nightingale is located - Nightingale itself comes into view at the end of the sequence (upper right). These are the closest images of the Nightingale crater captured to date.Date Taken: August 11, 2020Instrument Used: OCAMS (MapCam)Credit: NASA/Goddard/University of Arizona