With rubble from an asteroid tucked inside, a NASA spacecraft fired its engines and began the long journey back to Earth on Monday, leaving the ancient space rock in its rearview mirror.
The trip home for the robotic prospector, OSIRIS-REx, will take two years.
OSIRIS-REx reached asteroid Bennu in 2018 and spent two years flying near and around it before collecting rubble from its surface last fall.
The University of Arizona’s Dante Lauretta, the principal scientist, estimates the spacecraft holds between 200 grams and 400 grams of mostly bite-size chunks. Either way, it easily exceeds the target of at least 60 grams.
It will be the biggest cosmic haul for the U.S. since the Apollo moon rocks. While NASA has returned comet dust and solar wind samples, this is the first time it’s gone after pieces of an asteroid. Japan has accomplished it twice, but in tiny amounts.
WATCH | NASA’s OSIRIS-REx spacecraft collects asteroid sample:
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