Dec 12, 2019 - Science

NASA picks a sample site for asteroid mission

The sample site chosen by NASA on Asteroid Bennu, a grey asteroid with scattered boulders
OSIRIS-REx's chosen landing site on Bennu. Photo: NASA/Goddard/University of Arizona

NASA's OSIRIS-REx spacecraft — designed to snag a piece of an asteroid and deliver it back to Earth — officially has a sample collection site.

Why it matters: Asteroids are thought to be leftovers from the dawn of the solar system, so the sample that OSIRIS-REx gets from the asteroid Bennu could help scientists piece together the history of planetary formation and even how organic compounds made it to Earth.

Details: The sample site was carefully picked by mission controllers after a year of studying Bennu's rocky surface.

  • The site — named Nightingale — is in a crater in the northern part of the asteroid.
  • Nightingale contains smooth surface material that has likely been well-preserved by cold temperatures, making the site relatively safe and scientifically interesting for the spacecraft to sample, NASA said.
  • When the time comes, OSIRIS-REx will perform a touch-and-go maneuver that will bring the spacecraft's sampler into contact with the asteroid's surface for about five seconds before the orbiter moves away from the space rock.

Yes, but: Nightingale still comes with risks.

  • There is an area of only 52 feet within Nightingale that's safe for OSIRIS-REx to touch, meaning the spacecraft will need to be very exact in order to sample safely.
  • NASA has also selected a site called Osprey as a backup sample site if Nightingale doesn't work out.

The intrigue: Bennu's boulder-heavy surface has complicated the hunt for a safe sample site.

  • "The team has adapted by employing a more accurate, though more complex, optical navigation technique to be able to get into these small areas," Rich Burns, OSIRIS-REx project manager said in a statement. "We'll also arm OSIRIS-REx with the capability to recognize if it is on course to touch a hazard within or adjacent to the site and wave-off before that happens."

What's next: In January, OSIRIS-REx will continue to fly over Nightingale and Osprey, mapping out the two sites in great detail through the spring, NASA said.

  • Once mapped, the probe will rehearse its sample collection before making its first sampling attempt in August 2020.
  • OSIRIS-REx is expected to leave Bennu behind in 2021 and return to Earth two years later, in 2023.

Go deeper: NASA spacecraft arrives at near-Earth asteroid Bennu

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