NASA’s OSIRIS-REx arrived at asteroid Bennu in December 2018. Through the previous 12 months, it’s been imaging the floor of the asteroid extensively, searching for a spot to take a pattern from. Although the spacecraft has a number of science goals, and a set of devices to satisfy them, the pattern return is the important thing goal.
Now, NASA has narrowed the selection all the way down to 4 potential sampling areas on the floor of the asteroid.
The spacecraft carried out a month lengthy flyover of every of the 4 websites. That part was referred to as Recon A, and it was accomplished in July. Now mission operators have high-resolution photos of every of the websites, detailing their topography, albedo, colour, and the sampling suitability.
Now it’s time to slender the 4 websites down to 2: a main web site and a back-up web site. However sadly, Recon A confirmed that every of the 4 websites is hard, and sampling may not go as easily as hoped. Although every of the 4 websites has appropriate fine-grained materials, smaller than 2.5 cm (1 inch), they’re additionally hazardous.
One of many 4 potential sampling websites with a parking zone overlaid for scale. Picture Credit score: NASA/Goddard/College of Arizona
“Pattern web site choice actually is a complete exercise. It requires that we take a look at many several types of knowledge in many alternative methods to make sure the chosen web site is the only option by way of spacecraft security, presence of sampleable materials, and science worth,” mentioned Heather Enos, OSIRIS-REx deputy principal investigator on the College of Arizona, Tucson, and chair of the pattern web site choice board. “Our staff is extremely revolutionary and built-in, which is what makes the choice course of work,” she mentioned in a press launch.
Bennu is rougher than anticipated, and that’s including some complication to the sampling web site choice. OSIRIS-REx was designed to land on a beach-like floor, the place there are pond-like deposits of fine-grained materials appropriate for sampling. However Bennu is rocky. There are not any giant beach-like areas, there are solely small open areas surrounded by boulders.
This picture exhibits a view throughout asteroid Bennu’s southern hemisphere and into area, and it demonstrates the quantity and distribution of boulders throughout Bennu’s floor. The picture was obtained on Mar. 7 by the PolyCam digicam on NASA’s OSIRIS-REx spacecraft from a distance of about three miles (5 km). The big, light-colored boulder slightly below the middle of the picture is about 24 ft (7.four meters) large, which is roughly half the width of a basketball court docket. Picture Credit score: NASA/Goddard/College of Arizona
When OSIRIS-REx does finally take a pattern, it should achieve this autonomously. The spacecraft has a Pure Function Monitoring (NFT) system that makes use of photos of the asteroid to information itself to the floor. By evaluating its onboard photos of Bennu with what its cameras are seeing in actual time, it could actually keep away from collisions.
However Bennus’s surprising inhospitability signifies that system will face some challenges. It has an automated fail-safe that can abort the sampling if an impediment is simply too shut. To forestall that from occurring, mission operators might be working additional time. Actually, the staff nearly expects the spacecraft to waive its first try when it approaches the building-sized boulders that litter the floor of the asteroid.
“If the spacecraft executes a wave-off whereas making an attempt to gather a pattern, that merely signifies that each the staff and the spacecraft have completed their jobs…”
Mike Moreau, OSIRIS-REx Deputy Mission Supervisor.
“Bennu’s challenges are an inherent a part of this mission, and the OSIRIS-REx staff has responded by creating sturdy measures to beat them,” mentioned Mike Moreau, OSIRIS-REx deputy challenge supervisor at Goddard. “If the spacecraft executes a wave-off whereas making an attempt to gather a pattern, that merely signifies that each the staff and the spacecraft have completed their jobs to make sure the spacecraft can fly one other day. The success of the mission is our first precedence.”
Credit: NASA/Goddard/College of Arizona
However NASA nonetheless has to decide on one of many 4 potential avian-themed websites: Sandpiper, Osprey, Kingfisher, and Nightingale.
Sandpiper has the proper kind of fine-grained materials for a very good pattern, however the materials is trapped between bigger rocks, making it problematic. Total, the Sandpiper location is comparatively flat.
Web site Sandpiper is positioned in asteroid Bennu’s southern hemisphere, and the area of curiosity is seen within the heart of the picture (located above the big boulder). The picture was taken by the PolyCam digicam on NASA’s OSIRIS-REx spacecraft on October 5, from a distance of zero.6 miles (1 km). The sphere of view is 48 ft (14.6 m). For scale, the big, mild coloured boulder within the backside heart of the picture is 16 ft (5 m) large, which is concerning the measurement of a field truck. Picture Credit score: NASA/Goddard/College of Arizona
Initially, Osprey regarded promising. Spectrometry revealed that it has darkish carbon-rich materials that’s fascinating scientifically. Pictures additionally confirmed fine-grained materials, however high-resolution photos present that it’s scattered with bigger materials that’ll make sampling troublesome.
Web site Osprey is positioned close to asteroid Bennu’s equator within the northern hemisphere. As a result of the area of curiosity is so giant, solely a portion of the crater is proven on this picture. Web site Osprey’s recognizable options are seen – there’s a darkish patch of fabric within the heart of the crater, and a big, flat boulder on the northern crater wall (higher left). The picture was taken by the PolyCam digicam on NASA’s OSIRIS-REx spacecraft on October 12, from a distance of zero.6 miles (1 km). The sphere of view is 47 ft (14.2 m). For reference, the fracture within the giant boulder (higher left) is 10 ft (three m) lengthy, which is concerning the size of a standing grizzly bear. Picture Credit score: NASA/Goddard/College of Arizona
The Kingfisher web site is inside a small crater, which means it’s a youthful characteristic than different components of Bennu’s floor, together with the big crater that holds Sandpiper. Youthful craters maintain brisker materials, which hasn’t been subjected to as a lot space-weathering as older options. Kingfisher could also be too rocky, however one other close by crater could also be extra appropriate.
Web site Kingfisher is positioned close to asteroid Bennu’s equator within the northern hemisphere. The location itself is seen within the decrease proper of the picture, positioned in the midst of the comparatively clear area. The picture was taken by the PolyCam digicam on NASA’s OSIRIS-REx spacecraft on October 19, from a distance of zero.6 miles (1 km). The sphere of view is 47 ft (14.four m). For reference, the small crater is 9 ft (2.7 m) throughout, which is concerning the size of a dolphin. Picture Credit score: NASA/Goddard/College of Arizona
This crater web site has accessible fine-grained materials, though a single close by boulder might be hazardous. Additionally, it’s additional north, which means the lighting might make it troublesome for the autonomous NFT to acknowledge hazards.
Web site Nightingale is positioned close to asteroid Bennu’s north pole. The crater’s heart is seen within the high heart of the picture, which accommodates an accumulation of smaller rocks. The picture was taken by the PolyCam digicam on NASA’s OSIRIS-REx spacecraft on October 26, from a distance of zero.6 miles (1 km). The sphere of view is 47 ft (14.four m). For reference, the light-colored boulder (far left heart) is 5 ft (1.four m) lengthy, which is concerning the size of a bicycle. Picture Credit score: NASA/Goddard/College of Arizona
NASA is simply days away from narrowing the 4 websites down to 2. As soon as the first and backup websites are recognized, additional recon flights subsequent Spring will put together the staff for the eventual sample-taking maneuver. That maneuver is scheduled for subsequent Summer time, with the pattern arriving again right here at Earth in September 2023.