NASA’s Asteroid mission completes final test before sampling

While we were all busy watching the Perseverance rover depart on its journey to Mars, NASA’s asteroid sampling mission braced for its big moment. The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx for short) has completed its final surface test approach. The next time it descends, OSIRIS-REx will pick up pieces of the asteroid Bennu to return them to Earth.

NASA launched OSIRIS-REx in 2016, sending it to intercept 101955 Bennu, a carbonaceous asteroid about 490 meters in diameter. Bennu is really getting closer to Earth at certain points in its orbit – there’s even a small chance this will impact Earth over the next few centuries. Currently it is out of the way about 2 AU away (one AU is the distance between the Earth and the sun).

OSIRIS-REx met Bennu in 2018 and the team set to work to find a landing zone. NASA ran into the same problem as the Japanese team Hayabusa2 – Bennu was much steeper than expected. To take a sample, OSIRIS-REx must come into contact with the surface, which is dangerous with uneven surfaces and rocky prominences everywhere. Eventually, NASA selected several potential sites, naming them after the birds. The Nightingale site, which is in a crater near the asteroid’s north pole, prevailed.

On August 11, OSIRIS-REx completed its second dress rehearsal for the real deal. The spacecraft fired its engines to exit “safe house orbit” and descend to approximately 410 feet (125 meters) above the surface. On the way down, OSIRIS-REx matched Bennu’s rotation and came to an altitude of just 131 feet (40 meters) above Nightingale. In the video above, you can see Nightingale come into view at the top of the frame near the end. At this point the engines fired again to return OSIRIS-REx to a safe orbit.

Once the practice is over, the team can focus all of their efforts on the October 20 sample collection operation. On that day, OSIRIS-REx will descend completely and kiss Bennu’s surface with his sampling arm. A puff of nitrogen gas will (hopefully) launch Bennu particles into the sample container. NASA hopes to collect around 60 grams of material from Bennu. After collection, OSIRIS-REx will return to Earth with its precious cargo. The return capsule is currently scheduled to land in September 2023.

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