NASA’s ambitious origins, spectral interpretation, resource identification, safety, Regolith Explorer (OSIRIS-REx) has been in the orbit of the asteroid Bennu since 2018, but is preparing to call it the day and head home. NASA reports that OSIRIS-REx completed its mission profile at the last minute: Bennu’s last flight to see how its activities changed the surface of the facility.
OSIRIS-REx arrived in Benn in late 2018, but NASA spent nearly two years studying the space rock before OSIRIS-REx went into business. The spacecraft’s Touch-and-Go (TAGSAM) sampling mechanism allowed it to descend and tap the asteroid, releasing a burst of compressed nitrogen. OSIRIS-REx did just that at the end of 2020, collecting what could be more than that two pounds regolith. NASA would consider the mission successful with only 60 grams.
NASA says OSIRIS-REx will leave Benna on May 10th. The wait is long, mostly thanks to orbital mechanics – if a spacecraft waits for May to leave orbit, it will use less fuel to return to Earth. It also gave the team time to plan the now-completed final tour, which took place early on April 7th.
OSIRIS-REx spent almost six hours filming Bennu during a pre-programmed maneuver. It covered more than the complete rotation of the asteroids, but the area around the nightingale sampling site will be the most interesting. “By exploring the distribution of excavated material around the TAG site, we will learn more about the nature of surface and underground materials along with the mechanical properties of asteroids,” said Dr. Dante Lauretta, Principal Investigator for OSIRIS-REx at the University of Arizona.
After the overflight, all NASA needs to do now is download the data. That, however, is easier said than done. At a distance of 185 million miles (297 million kilometers), the Deep Space Network can only control a data rate of 412 kilobits per second. In addition, OSIRIS-REx must share time online with other NASA space missions. With only a few hours of downloads a day, NASA expects it will take another week to collect multiple gigabytes of OSIRIS-REx data.
After launching on May 10, OSIRIS-REx will need two years to return home. A container with intact samples of an ancient asteroid should land at the testing and training ground in Utah on September 24, 2023.