On a roll
Already, OSIRIS-REx has returned an impressive amount of science in the nearly two years since it arrived at Bennu. On October 8, mission researchers published six papers in the journals Science and Science Advances covering a wide range of Bennu’s unique characteristics and mysteries.
They include another surprise that greeted OSIRIS-Rex when it arrived: the asteroid has an active surface, with eruptions of coin-sized pebbles that fly off into space, ejected by causes that remain undetermined. “It was a little scary at first,” said Lauretta. But, he added, it wound up being a “real bonanza” for studying Bennu’s gravitational field.
“They get accelerated by solar radiation pressure — kind of like a light sail — and they launch into orbit, and they go around the asteroid for multiple revolutions, before re-impacting back on the surface,” explained Lauretta. “And because we have hundreds of them, this allowed us to probe the gravity field of Bennu at a scale we never thought possible when we were designing the mission.”
The gravity measurements indicate that Bennu’s density isn’t constant throughout, though. Instead, it’s clumpy, with denser regions towards the poles and less dense material at its core and equator, “It’s as if there is a void at its center, within which you could fit a couple of football fields,” said study leader Daniel Scheeres of the University of Colorado Boulder in a press release.
Another completely unexpected find was that Bennu’s surface ages differently from other asteroids and the Moon: typically, those bodies turn dark and red as they are bombarded by cosmic rays and micrometeorites. But Bennu turns blue as it weathers and becomes brighter. “This is an exciting finding because it tells us that something about Bennu is quite different from planetary surfaces we’ve observed,” Daniella DelleGuistina, a research scientist at the University of Arizona who led the work, tells Astronomy.
DelleGuistina hopes to further investigate this behavior with samples returned from Bennu. The Nightingale target site is relatively pristine, so researchers could try to recreate the space weathering process in the lab, using high energy lasers to shock and irradiate the samples, then observe what chemical changes cause the bluing, she says.
19th March 2018 — Mysterious plumes of particles coming from Asteroid Bennu
This view of asteroid Bennu ejecting particles from its surface on January 19 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
In January and February the OSIRIS Team reported detecting particles which were orbiting or surrounding the asteroid Bennu and were studying them in order to determine the nature of these objects. They have now announced that these particles are being ejected from the surface of the asteroid in plumes.
To say that this was unexpected is an understatement. On objects like comets which contain ice and other volatile compounds which can turn to gas as they approach the Sun and get warmed, out-gassing is expected which can cause particles to be ejected from the surface. However asteroids which are thought to have circled the Sun at an (approximately) constant distance would, if they originally contained such volatile compounds, have been expected to finish out-gassing millions of years ago.
These particle plumes were first detected (Jan 6) and then 11 bursts in the next two months. This happens to coincide with the asteroids perihelion (closest point to the Sun) when the asteroid is at it’s warmest, giving speculation that volatile substances under the surface are causing the plumes.
The detected particles range in size from about a centimetre to tens of centimetres across with speeds of up to several miles per hour. This is enough that some particles are ejected into space never to return, but others fall back or go in orbit for a while before falling back onto the asteroid.
The OSIRIS team are trying to analyse (and get more) data before speculating themselves as to what is causing the plumes.
This image shows a view across asteroid Bennu’s southern hemisphere and into space, and it demonstrates the number and distribution of boulders across Bennu’s surface. The image was obtained on Mar. 7 by the PolyCam camera on NASA’s OSIRIS-REx spacecraft from a distance of about 3 miles (5 km). The large, light-colored boulder just below the center of the image is about 24 feet (7.4 meters) wide, which is roughly half the width of a basketball court.
Credits: NASA/Goddard/University of Arizona
As well as plumes of particles to contend with, the fact that the surface of Bennu is boulder strewn rather than smaller particles such as dust or gravel, makes the task of obtaining a sample from the surface much harder. The team need to find a target area comprised of finer particles to sample and in a clear area without large boulders that might hamper the descent or ascent.
Articles: NASA, Spaceflightnow
Visiting Apophis
Apophis is another potentially hazardous asteroid that was recently removed from the which keeps track of asteroids where an Earth impact cannot be ruled out.
According to NASA, Apophis has been deemed to not be a problem for , based on improved simulations of its movements through space. On Friday, April 13, 2029, Earth will have a close encounter with the asteroid that will see the 1,120 feet (340-meter) wide object come just 19,000 miles (31,000 km) from the planet — closer than most geostationary satellites.
Previously, scientists calculated Apophis had a very small chance of hitting Earth during a flyby in 2068, but the reassessment of its risk in 2021 showed there is no threat whatsoever to worry about. But with the asteroid coming so close, having a healthy and untasked spacecraft available to swing by presented NASA with a unique moment.
NASA announced in April 2022 that it will redirect OSIRIS-REx to make the most of the encounter, and rename the spacecraft after it drops off Bennu samples at Earth. OSIRIS-APEX will be the new name of the mission in 2023 and it will reach Apophis in 2029.
The mission does take on some aging risk (as OSIRIS-Rex will be about 13 years old during the flyby) as well as the extra cost, as there will be another $200 million added bringing the total cost of $1 billion for a mission from Earth to Bennu to Apophis. That said, the cost is likely smaller than launching a separate, second spacecraft and dispenses with one of the riskiest phases of a new mission, which is blasting off the planet on a rocket.
Aside from one of the transmitters of OLA, the instruments on the spacecraft are healthy and that will allow the new OSIRIS-APEX mission to do its job. The spacecraft will examine Apophis for 18 months and aims to get close enough to examine the asteroid in great detail, including what lies beneath the surface. A special thruster maneuver will blast away the surface to reveal subsurface materials on Apophis
This will be especially helpful as Apophis and Bennu, despite being about the same size, are completely different asteroid types. Apophis shares the S-type family with ordinary chondrite meteorites, and Bennu is part of a family that potentially delivered water to Earth long ago (known as the B-type.)
Why Bennu?
Originally known as 1999 RQ36, the rock OSIRIS-Rex visited was renamed Bennu by 9-year-old Mike Puzio in a 2013 contest. Bennu is an Egyptian god usually depicted as a gray heron. Puzio chose the name because he thought TAGSAM and the solar panels resembled the bird god’s neck and wings.
Bennu is one of several thousand near-Earth objects orbiting within 120 million miles (190 million km) of Earth. Among those, Bennu was one of less than 200 objects whose orbit was well-known and sufficiently similar to Earth’s orbit. This asteroid orbits the sun every 436 days and comes very close to Earth every six years.
Bennu’s also relatively large, at about 1,650 feet (500 m) wide. Rocks smaller than 650 feet (200 m) spin too rapidly for a spacecraft to safely land on them. Only a handful of the asteroids in appropriate orbits were large enough to allow a visit.
Among those deemed appropriate, Bennu has a more-attractive composition. The asteroid is relatively rich in carbon-based material; the asteroids that may have brought water and organic material to Earth and helped kick off life would have looked like Bennu.
Bennu’s close orbit also makes it a for Earth, and NASA now estimates the risk is quite low: the asteroid’s total impact probability through 2300 is just 1 in 1,750. If the asteroid does collide with Earth, the impact won’t destroy the planet, but it will wreak havoc wherever it touches down. Experts say that an asteroid of this size would likely devastate the local area around the impact, but it wouldn’t cause mass extinctions.
Still, the advanced warning provided by OSIRIS-REx could help scientists take preventative measures long before an impact. One such method could be to redirect the asteroid entirely using the «kinetic impactor» technique as demonstrated by NASA’s DART mission. On Sept. 26, 2022, DART (Double Asteroid Redirection Test) successfully slammed a spacecraft into a small asteroid called Dimorphos to alter its orbit. The mission was a roaring success and on Oct. 11, 2022, NASA officially announced that DART shortened Dimorphos’ nearly 12-hour orbit by a whopping 32 minutes, smashing previous estimates.
Schedule:
|
Phase name |
Description |
Start time |
|
Launch |
Launch on an EELV from Cape Canaveral on an Earth-escape trajectory |
8th Sept. 2016 |
|
Outbound cruise |
Perform deep space maneuver; Earth flyby & gravity assist; instrument calibration & checkout |
Oct. 2016 |
|
Approach |
Perform braking maneuvers; survey the Bennu orbital environment for natural satellites; collect the first resolved images |
Aug. 2018 |
|
Preliminary survey |
Estimate the mass of Bennu; refine shape and spin state models |
Nov. 2018 |
|
Orbital A |
Demonstrate orbital flight; transition to landmark-based optical navigation |
Dec. 2018 |
|
Detailed survey |
Spectrally map the entire Bennu surface; collect images and lidar data for global shape and spin state models; search for dust plumes |
Jan. 2019 |
|
Orbital B |
Collect lidar and radiometric data for high resolution topographic map and gravity model; observe candidate sampling sites and down-select for reconnaissance |
Mar. 2019 |
|
Reconnaissance |
Conduct sorties for closer look at up to 4 candidate sampling sites and select 1 |
May 2019 |
|
TAG rehearsal |
Systematically and deliberately practice steps of sample collection sequence |
Aug. 2019 |
|
Sample collection |
Collect >60g (Level 2 requirement) of pristine bulk regolith and 26 cm2 of surface material, and stow it in the SRC (Sample Return Capsule) |
Sept. 2019 |
|
Quiescent operations |
Remain in Bennu’s heliocentric orbit; monitor spacecraft health |
Oct. 2019 |
|
Return Cruise |
Transport the sample back to the vicinity of the Earth |
Mar. 2021 |
|
Earth Return & Recovery |
Get the sample safely to the ground and to the curation facility in late September 2023 |
Sept. 2023 |
Астероиды как источники воды
Ученые считают, что астероиды, подобные Бенну, могли на начальных стадиях формирования нашей планеты доставить на Землю важные для жизни элементы, например, воду. Изучение этого образца может предоставить ответы на давние вопросы о происхождении нашей Солнечной системы.
Между тем космический аппарат, который доставил образец, теперь получил новое название — OSIRIS-APEX. Он отправляется на изучение околоземного астероида Апофис, который в 2029 году приблизится к Земле настолько, что его можно будет увидеть невооруженным глазом.
Ранее мы сообщали о том, что неожиданный состав астероида Бенну поразил ученых.
По материалам CNN.
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24th September 2023 — OSIRIS Successfully returns it’s sample to Earth before heading off to find another asteroid.
After separating from the spacecraft, on 24 September 2023 at about 2:42 a.m UTC, the OSIRIS-REx return capsule re-entered Earth’s atmosphere. At 2:52 a.m UTC the OSIRIS-REx return capsule landed at Utah Test and Training Range, three minutes earlier than predicted. At 04:15 a.m. UTC, the capsule left the landing site by helicopter. The sample will be curated at NASA’s Astromaterials Research and Exploration Science Directorate (ARES) and at Japan’s Extraterrestrial Sample Curation Center.
On 25 April 2022, NASA confirmed that the mission would be extended. After dropping off its sample to Earth on 24 September 2023, the mission became OSIRIS-APEX (‘APophis EXplorer’). As its new name suggests, its next target will be the near-Earth asteroid (and potentially hazardous object) 99942 Apophis. Apophis will make an extremely close pass to the Earth on 13 April 2029. Observations of Apophis will commence on 8 April 2029, and a few days later, on 21 April, OSIRIS-APEX is planned to rendezvous with the asteroid. OSIRIS-APEX will orbit Apophis for around 18 months in a regime similar to that at Bennu. The spacecraft will perform a maneuver, similar to sample collection at Bennu, by using its thrusters to disturb Apophis’s surface, in order to expose and spectrally study the subsurface and the material beneath it
31st December 2018 — OSIRIS enters orbit — and the record books.
At 2:43 p.m. EST on December 31, NASA’s OSIRIS-REx spacecraft, 70 million miles (110 million kilometres) away, carried out a single, eight-second burn of its thrusters – and broke a space exploration record. The spacecraft entered into orbit around the asteroid Bennu, and made Bennu the smallest object ever to be orbited by a spacecraft.
Up until now OSIRIS has accompanied Bennu in it’s orbit about the Sun, but has not been in orbit around Bennu. This is because Bennu is quite small (60-80 million metric tonnes) and has a very weak gravitation pull. OSIRIS has now moved be 1.75 kilometres from Bennu’s Centre (about 1.5km above the surface) and completing each orbit in around 62 hours. That’s an orbital speed of about 5cm per second. Article.
How it started
The $800-million OSIRIS-REx (Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer) mission was named a finalist for NASA’s New Frontiers mission class in 2009, along with missions to study Venus (Surface and Atmosphere Geochemical Explorer, or SAGE) and the moon (MoonRise). In 2011, OSIRIS-REx was chosen as the winning proposal.
The New Frontiers program consists of a series of medium-class spacecraft missions intended to help us better understand the solar system. OSIRIS-REx was the third mission chosen for that program; the previous selectees were New Horizons, which flew by the dwarf planet Pluto in 2015 and by an object called 2014 MU69 in 2019 and is continuing its mission out in the solar system, and the Juno mission, which arrived in orbit around Jupiter in 2016 and is still operational there.
OSIRIS-REx launched on Sept. 8, 2016. It briefly returned home in September 2017 to complete a speed-boosting flyby of Earth. The probe arrived at Bennu on Dec. 3, 2018. In the month after its arrival, OSIRIS-REx took detailed measurements of Bennu’s shape and mass before precisely slipping into orbit.
The asteroid probe set two records: Bennu is the smallest body a spacecraft has ever orbited (the space rock has a diameter of 1,640 feet, or 500 meters), and OSIRIS-REx performed the closest orbit ever of a small body, at just 1 mile (1.6 kilometers) from the surface.
OSIRIS-REx
This mission could help to save the world… quite literally! Bennu is a 500 meter wide asteroid that crosses Earth’s orbit and has a low probability (about 0.04%) of hitting the earth in the next 200 years. This mission allows this asteroid to be studied in great detail and will return samples of rock to Earth allowing better analysis than has ever been possible before. It will also allow a more accurate track of the asteroid to be determined so that we will have a better estimate of the chances of impact. Also knowing its structure will (hopefully) allow scientists to develop ways of changing its (or any similar objects) orbit to protect the Earth if necessary.
Here as some videos that explain this exciting mission:
Астероид Бенну — это машина времени
Астероиды считаются остатками формирования нашей Солнечной системы. Они помогают ученым понять, как выглядели хаотичные ранние времена, когда возникали планеты
Однако околоземные астероиды также представляют угрозу для Земли, поэтому важно понимать их состав и орбиты для разработки методов защиты нашей планеты от подобных объектов
Капсула с образцами с астероида Бенну, доставленная NASA OSIRIS-REx на Землю вскоре после приземления в пустыне, в воскресенье, 24 сентября 2023 года. Авторство: NASA
В октябре 2020 года космический аппарат OSIRIS-REx использовал устройство TAGSAM (Touch-and-Go Sample Acquisition Mechanism), чтобы собрать образец с поверхности астероида Бенну. Он взял настолько много материала, что частицы разлетелись в космосе, а сам контейнер едва закрылся. Это вызвало заинтересованность ученых, которые рассчитывали на быстрый анализ этого материала после открытия канистры. Оказалось, что у них достаточно времени, поскольку анализ образцов из внешней части TAGSAM уже начат.
Параллельно с этим продолжается экспресс-анализ образца, собранного с поверхности головки TAGSAM, и он может дать первые результаты относительно материала, полученного с астероида Бенну. Команда ученых будет использовать электронные микроскопы, рентгеновские и инфракрасные приборы для углубленного исследования образца. Эти инструменты помогут определить химический состав материала, выявить наличие гидратированных минералов или органических частиц и изучить разнообразные типы минералов, которые присутствуют на астероиде.
Последовательность изображений, сделанных OSIRIS-REx во время отделения капсулы с образцами на Землю. Фото: NASA
11 октября первые образцы с астероида Бенну покажут общественности в прямом эфире на официальной странице NASA.
Only the beginning
The successful TAG event is cause for relief, but the team is not ready to pop the champagne just yet. The next week and a half are crucial for checking whether OSIRIS-REx actually picked up material from Bennu as designed.
In the coming days, researchers will issue a command to make the spacecraft pirouette in place with its robotic arm extended. The more debris that the robotic arm picked up, the more force it will take to speed up OSIRIS-REx’s rotation, allowing researchers to estimate the sample haul to within a few grams. On October 30, Zurbuchen will decide whether OSIRIS-REx packages its sample to return to Earth, or turns back to Bennu for a second sampling attempt.
Future missions to other small, primordial worlds are already in the works, such as a planned flight to the metallic asteroid Psyche. Lockheed Martin, which hosts OSIRIS-REx’s mission control, is also building NASA’s upcoming Lucy spacecraft, which will launch in late 2021 to visit the Trojan asteroids orbiting alongside Jupiter.
These smallest of worlds can help solve the biggest cosmic mysteries, and like an impatient detective on the case of a lifetime, Lauretta is looking forward to seeing Bennu’s clues. “I cannot wait to get those samples,” he says. “We’re going to have so much fun.”
This story has been updated to reflect the successful contact with Bennu.
Flying to an ancient world
Getting to Bennu has been a hard, 16-year journey for the mission team.
Though the mission was first conceived in 2004, NASA didn’t formally select it to fly until May 2011. Mere months later, OSIRIS-REx’s original leader, University of Arizona planetary scientist Mike Drake, died after a prolonged illness following liver failure. University of Arizona planetary scientist Dante Lauretta, Drake’s deputy, stepped into the role left by his mentor, and the mission has been carried out in Drake’s memory.
“It’s really achieving the magnificent dream that had,” says NASA associate administrator Thomas Zurbuchen, who was friends with Drake. “There’s a tremendous sense of achievement I’m sure he would have, a pride in the team, if he was here—and in spirit, we think he is.”
After launching on September 8, 2016, OSIRIS-REx traveled tens of millions of miles to arrive at Bennu in December 2018. Bennu is the smallest celestial body a spacecraft has ever orbited: a mere rubble pile less than 1,700 feet wide on average, barely held together by its own feeble gravity. In such tenuous conditions, even the subtlest forces can nudge OSIRIS-REx out of whack, such as the pressure of sunlight pushing against the spacecraft.
As a result, the OSIRIS-REx team has had to model the spacecraft’s behavior and check its orbit to an unprecedented degree. Without regular corrections, errors in OSIRIS-REx’s trajectory would add up quickly, eventually leaving researchers without an accurate sense of where the spacecraft is at any given time.
“We’ve set the world records for smallest orbit achieved and smallest body orbited, and there’s a reason that people haven’t done this before—it’s very difficult,” says Lockheed Martin’s Olivia Billet, a systems engineer on OSIRIS-REx. “It’s a whole new way to operate.”
Bennu’s landscape has also given NASA some nasty surprises. Prior to OSIRIS-REx’s launch, researchers expected the asteroid to have smooth, fine-grained “sandy beaches” on its surface. But once the spacecraft arrived, NASA learned that Bennu is actually covered with blocky boulders.
The terrain was far rougher than OSIRIS-REx had been designed for, so the engineering team had to update the spacecraft’s navigation software in the middle of the mission. To give this new software as much information to work with as possible, the OSIRIS-REx team mapped the asteroid’s entire surface to within two inches—by far the most detailed global map a spacecraft has made of another celestial body. “We really had to sharpen our pencils,” says Lockheed Martin’s Mark Fisher, OSIRIS-REx’s chief engineer.
1st October 2018 — OSIRIS-REx executed first approach manoeuvre
NASA’s OSIRIS-REx spacecraft executed its first Asteroid Approach Maneuver (AAM-1) today putting it on course for its scheduled arrival at the asteroid Bennu in December. The spacecraft’s main engine thrusters fired in a braking maneuver designed to slow the spacecraft’s speed relative to Bennu from approximately 1,100 mph (491 m/sec) to 313 mph (140 m/sec). The mission team will continue to examine telemetry and tracking data as they become available and will have more information on the results of the maneuver over the next week.
During the next six weeks, the OSIRIS-REx spacecraft will continue executing the series of asteroid approach maneuvers designed to fly the spacecraft through a precise corridor during its final slow approach to Bennu. The last of these, AAM-4, scheduled for Nov. 12, will adjust the spacecraft’s trajectory to arrive at a position 12 miles (20 km) from Bennu on Dec. 3. After arrival, the spacecraft will initiate asteroid proximity operations by performing a series of fly-bys over Bennu’s poles and equator. Article
Asteroid sampling missions
Asteroids are the bits and pieces left over from the formation of the planets, and as such, they serve as rudimentary blueprints of the early solar system. Studying them allows scientists to see what the early solar system was like and to get a handle on how planets formed.
OSIRIS-REx follows a long line of asteroid missions, and while it is the first to return samples to the United States, Japan already has returned two other similar missions. Hayabusa became the first spacecraft to bring a bit of an asteroid back to Earth in 2010. A successor Japanese sample-return mission, called Hayabusa2, did the same with asteroid Ryugu in 2020.
NASA’s Dawn mission, as another example, visited the asteroid Vesta before moving on to the dwarf planet Ceres. In contrast to the Dawn mission, however, OSIRIS-REx aims to bring home a piece of Bennu for in-depth laboratory studies that aren’t possible from orbit. The OSIRIS-REx team aims to collect at least 2 ounces (60 grams) of material to achieve their scientific goals.
As a secondary objective, OSIRIS-REx’s research is meant to provide further insight into potentially hazardous asteroid movements. (There’s nothing to worry about yet, despite decades of searching the skies, but research remains ongoing.) Both Bennu and Apophis have designations as «potentially hazardous» asteroids, but it is more a statistical description than anything meant to cause alarm.
Related: Just how many threatening asteroids are there? It’s complicated.
OSIRIS-REx will also help astronomers study the Yarkovsky effect on asteroids. This phenomenon occurs when heat from the sun provides a tiny push that alters the movement of an asteroid or other object. Although the push is minimal, it can build up over time, helping to change the path a space rock travels. But it can be challenging to study this effect, as it varies based on the shape of each asteroid.
Further reading
Read of the OSIRIS-REx mission. Learn more about the OSIRIS-REx mission . Check out this collection of OSIRIS-REx photo galleries from the .
References
Arizona Board of Regents. (2022.) OSIRIS-Rex: Asteroid Sample Return Mission — Galleries. Accessed Nov. 10, 2022 from:
Lockheed Martin. (2022.) OSIRIS-REx: Discovering the Origins of the Solar System. Accessed Nov. 10, 2022 from
NASA. (2020, Oct. 23.) NASA’s OSIRIS-REx spacecraft collects significant amount of asteroid. Accessed Nov. 10, 2022 from:
OSIRIS-REx instruments
The five instruments onboard the spacecraft studied, mapped and analyzed the asteroid in unprecedented detail:
- OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) — By measuring visible and near-infrared light, OVIRS hunted for organics and other minerals.
- OSIRIS-REx Thermal Emission Spectrometer (OTES) — Using the thermal infrared, OTES took Bennu’s temperature and mapped mineral and chemical abundances. Together, OVIRS and OTES mapped Bennu over a range of wavelengths to select the best site to sample the asteroid.
- OSIRIS-REx Camera Suite (OCAMS) — A three-camera suite to map Bennu. PolyCam, the largest, acquired the first images of Bennu, taking them from 1.2 million miles (2 million kilometers) out, and captured high-resolution images of the sample site. MapCam hunted for satellites and dust plumes around the asteroid, mapped it in color, and took photographs to create topographic maps. SamCam documented the collection of the sample and its capture.
- OSIRIS-REx Laser Altimeter (OLA) — By scanning the entire surface of Bennu, OLA will send back data to create highly accurate 3D models of the asteroid’s surface. One of the two Canadian-built lasers failed during the primary mission, but it was working beyond its expected instrument lifetime and collected all the information required for OSIRIS-REx to land, investigators said at the time.
- Regolith X-ray Imaging Spectrometer (RExIS) — Studying X-ray emissions of Bennu was expected to help with the creation of a map showing the abundance of different elements on the surface. Unlike other imaging instruments, RExIS examined the composition of the asteroid at the level of individual atomic elements.
July 2018 — Successful Second Deep Space Maneuver for OSIRIS-REx Confirmed
New tracking data confirms that NASA’s OSIRIS-REx spacecraft successfully completed its second Deep Space Maneuver (DSM-2) on June 28. The DSM-2 burn, which employed the spacecraft’s Trajectory Correction Maneuver (TCM) thruster set, resulted in a 37 miles per hour (16.7 meters per second) change in the vehicle’s velocity and consumed 28.2 pounds (12.8 kilograms) of fuel.
DSM-2 was OSIRIS-REx’s last deep space maneuver of its outbound cruise to Bennu. The next engine burn, Asteroid Approach Maneuver 1 (AAM-1), is scheduled for early October. AAM-1 is a major braking maneuver designed to slow the spacecraft’s speed from approximately 1,130 to 320 miles per hour (506.2 to 144.4 meters per second) relative to Bennu and is the first of four asteroid approach maneuvers scheduled in order to accomplish arrival on 3rd December 2018. Article.
Mission timeline
The spacecraft made two deep-space maneuvers after launch. The first took place on Dec. 28, 2016, and set the spacecraft up for its gravity assist with Earth.
Almost a year later, OSIRIS-REx made a flyby of our home planet, on Sept. 22, 2017, to pick up speed for its journey to Bennu.At its closest approach to Earth, over Antarctica, the spacecraft was roughly 10,700 miles (17,200 km) from the surface. The flyby increased OSIRIS-REx’s speed by about 8,500 mph (13,000 km/h) and was flawlessly executed. The spacecraft then continued on its journey to Bennu.
Along the way, the OSIRIS-REx snapped some stunning images of Earth and its moon from a distance of a little more than 3 million miles (5 million km).
On June 28, 2018, the spacecraft aced its second and final major deep-space maneuver before making a series of successful asteroid-approach operations to put it close to Bennu where it safely arrived on Dec. 3, 2018.
After the asteroid was studied in significant detail, scientists identified a region to sample, a rocky zone with the nickname of Nightingale. A flawless touchdown on Oct. 21, 2020, lasted just six seconds and brought the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) into play.
As OSIRIS-REx drew closer to the asteroid, TAGSAM blasted a sample of pure nitrogen gas at the rock’s surface. Regolith (dust and broken rock) blasted from the surface was pushed into the chamber of the sampler. OSIRIS-REx was tasked with collecting at least 2 ounces (60 g) of asteroid material, with a preference for 5 ounces (150 g) to account for any measurement errors. The spacecraft easily surpassed the primary goal of 2 ounces or 60 grams, NASA said after the attempt.
While the spacecraft collected enough on its first goal, OSIRIS-REx did carry three bottles of nitrogen gas to allow for multiple collection attempts. TAGSAM also was rated to carry as much as 70 ounces (2,000 g). (To weigh the sample in the low-gravity environment, scientists measured the angular acceleration of the spacecraft before and after the sample is collected.)
OSIRIS-REx finished its last flyover of Bennu on April 7, 2021, and departed for Earth on May 10 that year. The plan is for the sample capsule to return to Earth on Sept. 24, 2023, while the main spacecraft journeys on to Apophis for a 2029 rendezvous.
How to watch
Coverage on NASA’s livestream starts at 5 p.m. Eastern Daylight Time; the TAG attempt is scheduled for 6:12 p.m. EDT. You can also watch the livestream directly below.
However, we may not know whether the mission was fully successful until several days later. The team will examine images of TAGSAM and measure how much material it collected by setting the entire craft into a slow spin and noting its change in the moment of inertia.
NASA has scheduled a press conference for Wednesday at 5 p.m. EDT to announce preliminary results of the TAG attempt and release new images. But a detailed determination, including the mass measurement of the samples, may take a week or so, Lauretta said.
