(Dugway) The largest asteroid sample ever collected and the first for NASA landed in the Utah desert in the United States on Sunday, after a dizzying final descent through Earth’s atmosphere, seven years after the launch of the OSIRIS-REx probe.
Published at 10:55 am. Updated at 11:23 a.m
George FREY with Lucie AUBOURG in Washington Agence France-Presse
The crash, observed by army sensors, had to be stopped by two successive parachutes. However, the main parachute deployed higher than expected and the capsule landed slightly earlier than expected, a NASA commentator announced in his live video.
The sample taken from the asteroid Bennu in 2020 must contain around 250 grams of material, according to estimates by the American space agency, much more than the two previous asteroid samples reported by Japanese missions.
It should “help us better understand the types of asteroids that could threaten Earth” and shed light on “the beginnings of the history of our solar system,” emphasized space agency chief Bill Nelson.
“The return of this sample is truly historic,” NASA scientist Amy Simon said before landing. This is the “largest sample we have brought back of moon rocks” from the Apollo program, which concluded in 1972.
The area attacked on the ground was 58 km long and 14 km wide and was in a military area normally used for missile testing.
About four hours before the scheduled landing time, the OSIRIS-REx probe released the capsule containing the sample, more than 100,000 km from Earth (approximately 1/3 of the Earth-Moon distance).
In the last 13 minutes, this capsule crossed the atmosphere: it entered at more than 44,000 km / h, with the temperature rising to 2700 ° C.
The probe, in turn, set off to visit another asteroid.
Two Japanese samples
Once the capsule was on the ground, a team armed with gloves and masks had to check its condition before it was placed in a net, then lifted by a helicopter and taken to a makeshift “clean room.”
The capsule must be exposed to the sands of the American desert for as short a time as possible to avoid contamination of the sample, which could confound subsequent analyses.
On Monday it will be flown to the Johnson Space Center in Houston, Texas. Here the box is opened in another airtight room. The process will take days.
NASA is planning a press conference on October 11 to announce initial results.
The majority of the sample will be retained for study by future generations. About 25% will be used immediately for experiments and a small portion will be shared with partners Japan and Canada.
Japan itself gave NASA some grains of the asteroid Ryugu during the Hayabusa-2 mission, of which it returned 5.4 grams in 2020. In 2010, he reported a microscopic amount from another asteroid.
This time, the Bennu sample is “much larger, so we can do a lot more analysis,” Amy Simon said.
History of our origins
Asteroids are made from the primordial materials of the solar system 4.5 billion years ago. Unlike Earth, they remained intact.
They therefore have “clues to how the solar system formed and evolved,” said Melissa Morris, head of NASA’s OSIRIS-REx program, at a press conference. “It is the story of our own origins. »
By impacting our planet, “we believe that asteroids and comets brought organic matter, possibly water, that contributed to the development of life on Earth,” explained Amy Simon.
Scientists believe Bennu (500 meters in diameter) is rich in carbon and contains water molecules trapped in minerals.
The asteroid also surprised scientists: its surface turned out to be less dense than expected when the sample was taken. The arm of the probe was sunken, a bit like a ball pit.
However, a better understanding of its composition could prove useful in the future.
There is a small chance (1 in 2700 chance) that Bennu will hit Earth in 2182, a collision that would be catastrophic. But last year, NASA managed to divert the trajectory of an asteroid by hitting it.