Asteroid Bennu’s Surprising Surface Revealed by OSIRIS-REx

The lunar surface is better at resisting impacts than the loose surface of asteroid Bennu – thanks to the Moon’s much stronger gravity. Asteroid Bennu is a dark, jumbled mass of rocks and boulders left over from the formation of the solar system. Roughly the height of a skyscraper, Bennu’s loose surface materials are held together by an incredibly weak gravitational field – with a minute tug less than one-hundred-thousandth the pull of Earth. What would it be like to touch down on such an environment?On the Moon, gravity is sixteen percent as strong as it is on Earth and more than sixteen thousand times stronger than it is on Bennu. As a result, loose material in the lunar subsurface is packed together more tightly, making the Moon’s surface relatively firm. If a fifty-kilogram mass of solid iron were to hit the Moon traveling at ten centimeters per second, it would sink into the ground by only half a centimeter.Repeating this experiment at Bennu would yield a dramatically different result. Though the mass would strike the asteroid’s surface with the same force, it would plunge seventeen centimeters before stopping – over thirty times deeper than at the Moon.Learn more about the surface properties of asteroid Bennu.

Data-driven animation showing how the OSIRIS-REx spacecraft impacted asteroid Bennu s surface when it touched down and collected a sample. On October 20, 2020, NASA’s OSIRIS-REx spacecraft collected a sample of asteroid Bennu. The event revealed surprising details about Bennu’s surface and near-subsurface.00:01 - One second after contact, OSIRIS-REx injected Bennu with pressurized nitrogen gas, causing an explosion of particles and driving loose material into its sample collector.00:06 - Six seconds after contact, while it was still sinking into Bennu, OSIRIS-REx fired its thrusters to begin the back-away maneuver.00:09 - Nine seconds after contact, thrusters on board OSIRIS-REx halted its descent into Bennu, pushing it away from the asteroid, and blasting loose material from the sample site. The spacecraft’s arm had sunk almost half a meter beneath the surface – far deeper than expected, confirming that Bennu’s surface is incredibly weak.00:16 - Sixteen seconds after contact, the arm fully reemerged from the subsurface. OSIRIS-REx had collected a handful of material and kicked up roughly six tons of loose rock.00:30 - Thirty seconds after contact, it shut off its thrusters and drifted away from Bennu. OSIRIS-REx will return its sample to Earth in September 2023.Learn more about the surface properties of asteroid Bennu.

This visualization begins with a top-down view of a high resolution digital terrain model (DTM) of the Nightingale TAG sample site on Bennu. As the camera moves closer, data representing the surface height change pre-post TAG fades on. The surface height change as a result of the TAG event is represented by both a color map and by offsetting the original DTM to reveal the TAG crater. The DTM offset is applied to the surface region within ~7.5 meters of impact, which is highlighted for emphasis. With this color bar, yellows, greens, and blues represent a decrease in elevation, light red represents no change in elevation, and dark red represents an increase in elevation. Thruster marks and a region of ejected surface material are labeled. The camera does a 360 degree spin around the sample site before returning to a top-down view of the color-mapped data. The Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) spacecraft arrived at near-Earth asteroid Bennu in December 2018. After studying the asteroid for nearly two years, the spacecraft successfully performed a Touch-And-Go (TAG) sample collection maneuver on October 20, 2020. The change in surface topography as a result of the sample collection maneuver is observed by comparing pre-TAG and post-TAG digital terrain models (DTM), revealing the newly-formed TAG crater. OSIRIS-REx will return its sample of Bennu to Earth in September 2023. Same visualization as above, but without “Point of Impact,” and “Thruster Mark” labels Still image - Top-down view of a high resolution digital terrain model (DTM) of the Nightingale TAG sample site on Bennu. Still image - Oblique view of the Nightingale TAG sample site with the TAG impact location labeled. Still image - Oblique view of the TAG sample site with pre-post surface height change data represented by both a color map and by offsetting the original DTM to reveal the TAG crater. The DTM offset is only applied to the surface region within ~7.5 meters of impact, which is highlighted for emphasis. Still image - Oblique view of the TAG sample site with pre-post surface height change data represented by both a color map and by offsetting the original DTM to reveal the TAG crater. The DTM offset is only applied to the surface region within ~7.5 meters of impact, which is highlighted for emphasis. Additional surface features resulting from TAG are labeled. Still image - Top-down view of a high resolution digital terrain model (DTM) of the Nightingale TAG sample site on Bennu with pre-post surface height change data.

OSIRIS-REx leaving Bennu, returning to Earth. At approximately 4:16 p.m. EDT on May 10, 2021, the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft will fire its main thrusters for seven minutes and start its long journey home with more than 60 grams (2.1 ounces) of asteroid material in its Sample Return Capsule.OSIRIS-REx s path to intersect Earth and achieve a successful sample return at the Utah Test and Training Range on September 24, 2023, between 8 a.m. and 9 a.m. EDT.

Real-time animation of the OSIRIS-REx Touch-And-Go (TAG) Event. This animation accurately depicts the spacecraft s terrain. Broadcast playback was adjusted for the light-time delay from Bennu to Earth (plus signal processing), providing viewers with a real-time window onto the TAG Event.Highlights can be found at the following animation time steps (hours: minutes: seconds):00:29:03 - First move to Y-Wing configuration00:34:29 - Second move to Y-Wing configuration00:39:54 - Y-Wing configuration complete00:43:27 - Checkpoint engine burn start00:54:34 - Matchpoint engine burn start01:05:10 - TOUCH asteroid Bennu01:05:18 - Back-away engine burn start01:06:43 - Begin slew to Pegasus configurationAnimation frames are organized into chapters for ease of download.

The Checkpoint burn sends OSIRIS-REx toward sample site Nightingale. This media resource page provides animations of the OSIRIS-REx Touch-And-Go (TAG) event. OSIRIS-REx is NASA s surface for only a few seconds, OSIRIS-REx will fire its thrusters and back away to a safe distance with its precious cargo.

This visualization depicts the OSIRIS-REx TAG on October 20, 2020. The OSIRIS-REx satellite is represented by an orange dot and trail. The visualization begins with the satellite’s departure from orbit and continues through the checkpoint, matchpoint, TAG, and backaway maneuvers. On Oct. 20, the OSIRIS-REx spacecraft will perform the first attempt of its Touch-And-Go (TAG) sample collection event. This series of maneuvers will bring the spacecraft down to site Nightingale, a rocky area 52 ft (16 m) in diameter in Bennu’s northern hemisphere, where the spacecraft’s robotic sampling arm will attempt to collect a sample. Site Nightingale was selected as the mission’s primary sample site because it holds the greatest amount of unobstructed fine-grained material, but the region is surrounded by building-sized boulders. During the sampling event, the spacecraft, which is the size of a large van, will attempt to touch down in an area that is only the size of a few parking spaces, and just a few steps away from some of these large boulders.During the 4.5-hour sample collection event, the spacecraft will perform three separate maneuvers to reach the asteroid’s surface. The descent sequence begins with OSIRIS-REx firing its thrusters for an orbit departure maneuver to leave its safe-home orbit approximately 2,500 feet (770 meters) from Bennu s rotation at the time of contact. The spacecraft then descends to the surface, touches down for less than sixteen seconds and fires one of its three pressurized nitrogen bottles. The gas agitates and lifts Bennu’s surface material, which is then caught in the spacecraft’s collector head. After this brief touch, OSIRIS-REx fires its thrusters to back away from Bennu’s surface and navigates to a safe distance from the asteroid. This is a closer view of the TAG, focusing on the checkpoint, matchpoint, TAG, and backaway maneuvers. White labels appear to highlight checkpoint and matchpoint. The TAG location is indicated with a marker that changes from white to green once the TAG has occurred. This a closer view of the TAG in a Bennu-fixed reference frame. A thin green line shows the future trajectory of OSIRIS-REx down to the TAG site. White labels appear to highlight checkpoint and matchpoint maneuvers. The TAG location is indicated with a marker that changes from white to green once the TAG has occurred. This is a view of the TAG event from the perspective of the OSIRIS-REx spacecraft. The visualization begins with the satellite’s departure from orbit and continues through the checkpoint, matchpoint, TAG, and backaway maneuvers. This is a view of the TAG event from the perspective of the OSIRIS-REx spacecraft. The visualization begins with the satellite’s departure from orbit and continues through the checkpoint, matchpoint, TAG, and backaway maneuvers. This version is about four times slower than the previous version and includes more of the backaway. This is a slower view of the TAG event from the perspective of the OSIRIS-REx spacecraft. The visualization begins just after the checkpoint maneuver and continues through matchpoint, TAG, and backaway.

This first shot of the sequence begins with OSIRIS-REx’s arrival at the asteroid Bennu. A low resolution view of the asteroid is presented and thermal inertia data fades in, representing our initial understanding of the asteroid. The asteroid then spins quickly to serve as a transition to the second shot in the sequence. When NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu in December 2018, its close-up images confirmed what mission planners had predicted nearly two decades before: Bennu is made of loose material weakly clumped together by gravity, and shaped like a spinning top. This major validation, however, was accompanied by a major surprise. Scientists had expected Bennu’s surface to consist of fine-grained material like a sandy beach, but instead OSIRIS-REx was greeted by a rugged world littered with boulders – the size of cars, the size of houses, the size of football fields.This video explores several interesting features of Bennu. The surface features are presented in vivid detail thanks to detailed terrain data from the OLA instrument and high resolution imagery from the PolyCam instrument. This second shot in the sequence begins with a fast spinning Bennu, matching the end of the first shot in the sequence. As Bennu’s rotation decelerates, a highly detailed view of the asteroid is revealed using 20cm terrain elevation data (OLA) and high resolution imagery (PolyCam). The camera then zooms in and flys over several locations - Simurgh, Roc, Gargoyle, and Ocypete. Each of these locations are presented using 5cm terrain elevation tiles. The third shot of the sequence begins with a dramatic reveal of BenBen, the tallest boulder on Bennu. The shot begins in darkness and sunlight sweeps across the surface of the asteroid. The camera rotates down to the horizon to show the height of the boulder before zooming over to a view of two boulders found to contain pyroxene. The camera then zooms back out to a global view and we see OSIRIS-REx in orbit around the asteroid.

Looping animation of asteroid Bennu rotating. This 3D model of Bennu was created using 20cm resolution laser altimetry data and imagery taken by OSIRIS-REx. When NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu in December 2018, its close-up images confirmed what mission planners had predicted nearly two decades before: Bennu is made of loose material weakly clumped together by gravity, and shaped like a spinning top. This major validation, however, was accompanied by a major surprise. Scientists had expected Bennu’s surface to consist of fine-grained material like a sandy beach, but instead OSIRIS-REx was greeted by a rugged world littered with boulders – the size of cars, the size of houses, the size of football fields.The 3D animations on this page were created using laser altimetry data and imagery of Bennu taken by OSIRIS-REx.The Bennu albedo map was generated using images acquired by PolyCam during Baseball Diamond Flyby 1. The images were photometrically normalized to represent the innate albedo of Bennu’s surface. Details for the creation of the map can be found in the forthcoming publication “A High-Resolution Normal Albedo Map of Asteroid (101955) Bennu” by Golish et al. Icarus (2020). Polar regions that were not imaged in Flyby 1 are visualized using the Bennu global basemap, created from PolyCam images acquired during Baseball Diamond Flybys 3 and 4. Details for the creation of the basemap can be found in “A high-resolution global Basemap of (101955) Bennu” by Bennett et al. Icarus (2020). Looping animation of sunlight sweeping across the surface of Bennu. This 3D model of Bennu was created using 20cm resolution laser altimetry data and imagery taken by OSIRIS-REx. Print resolution (5760x3240 pixels) still image of Bennu. The Nightingale sample site is visible in the northern hemisphere. Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu. The Nightingale sample site is visible in the northern hemisphere. Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu Print resolution (5760x3240 pixels) still image of Bennu

OSIRIS-REx approaches Bennu After nine months in orbit around asteroid Bennu, OSIRIS-REx will begin the process of maneuvering closer to the surface in preparation of the sample collection event. Once the sample site has been selected, OSIRIS-REx will break from its polar orbit to practice three flyovers of the site at increasing proximities, eventually matching Bennu s soil. This will force loose dust, dirt, and rocks upward into the TAGSAM head, trapping the material inside. OSIRIS-REx will then weigh and stow the captured sample for return to Earth in 2023. TAG Arm Deploy TAG Arm Deploy Reverse OSIRIS-REx desending to Bennu OSIRIS-REx approach continued TAGSAM getting closer OSIRIS-REx almost there Contact OSIRIS-REx Pulls away TAG Maneuver Interior Cutaway OSIRIS-REx backs away from Bennu Sample Verification OCAMS SamCam Sample Verification OCAMS Sam Cam 2 Sample Mass Measurement Sample Stowage Sequence Sample Stowage Sequence Closeup OSIRIS-REx Stows the TAG Arm Returning to Earth