The OSIRIS-REx spacecraft completes one last flyby of the asteroid Bennu on Wednesday.
The spacecraft made history when it briefly touched the asteroid on October 20, 2020, collecting a large 2-ounce sample from the surface.
The sample, stored securely inside the spacecraft, will be returned to Earth in 2023.
The OSIRIS-REx mission, formally known as Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, first arrived on the asteroid in December 2018 and has been orbiting it ever since.
During Wednesday’s flyby, the spacecraft gets one last close-up of Bennu taking pictures of the asteroid’s surface from just 3.7 km away. The photos were to reveal the wake of the sample fundraising event in October, which was a messy affair.
The surface of the asteroid was disturbed when the sampling head of OSIRIS-REx sank 1
The gravity of the asteroid is weak, so rocks and dust were launched and scattered throughout the process.
Pictures taken of the spacecraft on Wednesday show scientists how much the sample collection event changed the surface of the asteroid. The spacecraft will spend nearly six hours imaging Bennu, allowing the cameras to watch the asteroid complete a full rotation.
The route of this flyby is known for OSIRIS-REx, which conducted a similar while searching for a landing site during surveys in 2019. These images from 2019 will be used along with the new images to create before and after comparisons.
During the airport, OSIRIS-REx’s instruments collect data, giving the mission team a chance to assess them after the tools were dusted during the collection event. The spacecraft may go on an extended mission after handing over Bennus’ test on Earth in September 2023, so this evaluation can help teams make that decision.
Days after flyby, all the images and data are sent back to the mission teams so they can analyze the changes in Bennu and evaluate the spacecraft’s instruments.
OSIRIS-REx will hang out in the area around Bennu until May 10, after which it will begin a two-year and 200 million mile journey back to Earth.
“Leaving Bennus’ proximity in May puts us in the ‘sweet spot’ when the takeoff maneuver will consume the least amount of spacecraft fuel on board,” said Michael Moreau, OSIRIS-REx Deputy Project Manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
“Nevertheless, at over 593 miles per hour (265 meters per second) with speed change, this will be the largest propulsion maneuver performed by OSIRIS-REx since the approach to Bennu in October 2018.”
The sample from the asteroid could shed more light on the formation of the solar system and how elements such as water may have been delivered to the early earth by shocks from asteroids.
When OSIRIS-REx approaches Earth in 2023, it will drop the capsule containing the sample, which shoots through the Earth’s atmosphere and parachutes into the Utah Desert.
A team will be ready to pick up the sample and transfer it to an aircraft hangar that serves as a temporary clean room. The sample will then be whipped away to laboratories currently under construction at the Johnson Space Center in Houston.
“OSIRIS-REx has already delivered incredible science,” Lori Glaze, NASA’s Director of Planetary Science, said in a statement. “We are really excited that the mission is planning another observation flight of the asteroid Bennu to provide new information on how the asteroid responded (the Touch-and-Go Sample Collection event) and to give a proper farewell.”