After seven years in space, NASA’s OSIRIS-REx spacecraft is returning to Earth carrying a precious payload: a sample canister loaded with up to 250 grams (8.8 ounces) or so of pebbles, dust and rocky debris collected from the surface of the asteroid Bennu in October 2020.
Shortly after their dramatic “touch-and-go” collection, the samples were sealed inside a small capsule that will be released to slam into Earth’s atmosphere in a blazing fireball on 24 September, descending by parachute to a military compound in Utah where recovery crews will be standing by.
After making sure the capsule is intact and free of any earthly contamination, it will be flown by helicopter to a temporary “clean room” where the internal sample container will be removed. From there, the precious samples will be flown by jet to the Johnson Space Center in Houston for the start of detailed laboratory analysis.
Project managers, engineers, contractor personnel and military support teams plan to spend the next six months refining and rehearsing the OSIRIS-REx recovery procedures to make sure the final stages of the 12-year project are successful.
“The OSIRIS-REx team has already performed amazing feats characterising and sampling asteroid Bennu,” said Dante Lauretta, OSIRIS-REx principal investigator from the University of Arizona, Tucson. “These accomplishments are the direct result of the extensive training and rehearsals that we performed every step of the way. We are bringing that level of discipline and dedication to this final phase of the flight operations.”
Bennu, like other asteroids strewn across the solar system, is thought to be made up of pristine materials left over from the formation of the sun and planets 4.5 billion years ago, possibly including some of the molecular precursors to life.
To understand whether asteroids might have brought such compounds to Earth, scientists need untouched samples, free of any possible contamination, to study.
“There are two things pervasive on Earth: water and biology,” said Dr. Jason Dworkin, OSIRIS-REx project scientist at NASA Goddard. “Both can severely alter meteorites when they land on the ground and muddle the story told by the sample’s chemistry and mineralogy. A pristine sample could provide insights into the development of solar system.”
All of that will come to a head on 24 September when OSIRIS-REx releases the sample canister on a trajectory leading to touchdown within a 59-by-15 kilometre (37-by-9 mile) ellipse within the U.S. military’s Utah Test and Training Range and Dugway Proving grounds.
Spacecraft-builder Lockheed Martin is keeping tabs on the spacecraft as it closes in on Earth and preparing to recover the sample capsule. This summer, recovery crews in Colorado and Utah will rehearse recovery procedures in Colorado and Utah while a curation team at the Johnson Space Center practices procedure to unpack and process the samples inside glove boxes.
While all of that is going on, members of the sample science team will be preparing the investigations they plan to perform once the samples are available.
“The return to Earth of samples from asteroid Bennu will be the culmination of a more than 12-year effort by NASA and its mission partners but marks the beginning of a new phase of discovery,” NASA said in a statement.
“Scientists from around the world will turn their attention to the analysis of this unique and precious material dating from the early formation of our solar system.”