Cleanliness was the watchword out in the desert. When the recovery teams caught up with the capsule on the ground, their motivation was to bring it back to a temporary clean room at the nearby Dugway army base as quickly as possible.

If, as researchers think, the sample contains carbon compounds that may have been involved in the creation of life then mixing the rocky material with present-day Earth chemistry has to be avoided.

"The cleanliness and preventing contamination of the spacecraft has been a really stringent requirement on the mission," said Mike Morrow, the Osiris-Rex deputy project manager.

"The best way that we can protect the sample is just to get it from the field into the clean lab that we've set up here in a hangar as quickly as possible and get it under a pure nitrogen gas purge. And then it's safe."

This was achieved just before 13:00 local time, a mere four hours after touchdown.

The lab team disassembled the capsule, removing its heatshield and back cover but leaving the sample secure inside an inner canister.