NASA’s first asteroid sample return mission, called OSIRIS-REx, is approaching a crucial phase of its operation, where it will touchdown on asteroid Bennu's surface to scoop up some material. Last month, the mission team completed one of its planned dress rehearsals, reaching its closest point to Bennu yet.
The second rehearsal and sample collection were previously scheduled for June and August respectively but are now slightly postponed. Due to the constraints necessary during the Covid-19 pandemic, the mission team decided to move the second rehearsal to August 11, when OSIRIS-REx will reach an unprecedented altitude of just 40 meters (131 feet) from the surface. The sample collection is now scheduled for October 20.
“In planning the mission, we included robust schedule margin while at Bennu to provide the flexibility to address unexpected challenges,” Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center, said in a statement. “This flexibility has allowed us to adapt to the surprises that Bennu has thrown at us. It’s now time to prioritize the health and safety of both team members and the spacecraft.”
The sampling event is a Touch-And-Go (TAG) collection. OSIRIS-REx will extend a sampling mechanism that will stay in contact with the surface of asteroid Bennu for about five seconds. A nitrogen charge will be fired to disturb the surface and allow the spacecraft to collect its sample. It is possible that OSIRIS-REx will collect enough material in one go, but if it doesn’t the spacecraft can perform two more TAG events.
“This mission’s incredible performance so far is a testament to the extraordinary skill and dedication of the OSIRIS-REx team,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “I am confident that even in the face of the current challenge, this team will be successful in collecting our sample from Bennu.”
OSIRIS-REx is expected to leave Bennu around mid-2021 and embark on a journey back to Earth for a return date of September 24, 2023. When it arrives, it will be the third spacecraft ever to return samples from an asteroid, following the Japanese Hayabusa and Hayabusa-2 crafts.