Seven years after takeoff, the capsule landed Sunday on Earth, in the American desert, at the end of a high-risk maneuver.

NASA estimates that in 2020 it has managed to collect about 250 grams of material from asteroid Bennu -- the largest asteroid sample ever collected.

At the time of this operation, the space agency had realized that the valve of the collection compartment could not close. But the cargo had finally managed to be secured by being transferred as planned to the capsule.

Because of this leak, however, scientists expected that residues would be found outside the collection compartment, in the box where it was placed.

A first lid was opened Tuesday in an airtight chamber at the Johnson Space Center in Houston, Texas.

NASA teams then immediately "found black dust and debris," NASA announced, without saying if they were indeed pieces of asteroid.

This material will be analyzed, and the "meticulous process of disassembly" of the collection compartment will take place, "in order to access the main sample inside" it, wrote the space agency.

A press conference is scheduled for October 11 to "unveil the sample".

The analysis of the composition of the asteroid Bennu should allow scientists to better understand the formation of the solar system, and how the Earth became habitable.

© 2023 AFP