The OSIRIS-REx spacecraft makes one last flight of the asteroid Bennu on Wednesday.
The spacecraft made history when it briefly touched the asteroid on October 20, 2020 and collected a 2-ounce sample from the surface.
The sample, kept safely inside the spacecraft, will be returned to Earth in 2023.
The OSIRIS-REx mission, officially known as Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, first arrived on the asteroid in December 2018 and has been orbiting ever since.
During Wednesday’s flight, the spacecraft will receive a final close-up of Bennu, capturing images of the asteroid’s surface just 3.8 miles away. The images should reveal the consequences of the October evidence-gathering event, which was a messy affair.
The asteroid’s surface was disturbed when the OSIRIS-REx sampling head sank 1.6 meters down the asteroid’s surface. Triggered a charge containing nitrogen gas to disrupt the surface material to facilitate sampling. The spacecraft’s propellers also launched material into the air as the spacecraft moved away from the asteroid after collecting the sample.
Gravity on the asteroid is weak, so rocks and dust have been released and scattered throughout the process.
Images captured by the spacecraft on Wednesday will show scientists how much the sampling event has altered the asteroid’s surface. The ship will spend almost six hours imagining Bennu, which will allow its cameras to see the asteroid completing a complete rotation.
The route of this flyby is familiar to OSIRIS-REx, which performed a similar one while searching for a landing site during the 2019 polls. These 2019 images will be used in conjunction with the new images to create before and after comparisons.
During the flight, OSIRIS-REx instruments will collect data, allowing the mission team the chance to evaluate them after the instruments have been covered with dust during the collection event. The spacecraft could go on an extended mission after leaving Bennu’s sample on Earth in September 2023, so this assessment can help teams make that determination.
A few days after the flight, all images and data will be sent back to the mission teams so that they can analyze the changes made to Bennu and evaluate the spacecraft’s instruments.
OSIRIS-REx will stay in the area around Bennu until May 10, then begin a two-year, 200 million-mile journey back to Earth.
“Leaving Bennu’s neighborhood in May puts us in the ‘sweet spot’ when the departure maneuver consumes the least amount of fuel aboard the spacecraft,” said Michael Moreau, deputy director of the OSIRIS-REx project at the NASA’s Goddard space flight from Greenbelt, Maryland, in a statement.
“However, at over 593 miles per hour (265 meters per second) of gear change, this will be the largest propulsion maneuver performed by OSIRIS-REx since near Bennu in October 2018.”
The asteroid sample could shed more light on the formation of the solar system and how elements such as water could have been delivered to Earth early by the impact of asteroids.
Once OSIRIS-REx approaches Earth in 2023, it will drop the sample-containing capsule, which will shoot through the Earth’s atmosphere and parachute into the Utah desert.
A team will be ready to retrieve the sample and transfer it to an aircraft hangar that will serve as a temporary clean room. The sample will then be taken to laboratories that are currently under construction at the Johnson Space Center in Houston.
“OSIRIS-REx has already provided 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 of the Bennu asteroid to provide new information on how the asteroid reacted (the Touch-and-Go Sample Collection event) and to say goodbye.”
