Seven years after its takeoff, the Osiris-Rex probe accomplished its mission: to deliver to humanity the largest asteroid sample ever collected in space, and the first by NASA.
The capsule containing the sample landed on Sunday in the Utah desert in the United States, at the end of a dizzying final descent through the Earth’s atmosphere, which began at 44,000 km/h.
The fall, observed by army sensors, was slowed by two successive parachutes, allowing the desired speed of around 17 km/h to be reached when it hit the ground.
Approximately 20 minutes later, a team arrived on site to check the condition of the capsule.
NASA confirmed that no breach had been observed.
“Congratulations to the Osiris-Rex team,” said NASA boss Bill Nelson during the space agency’s live video. This mission “reported something extraordinary, the largest asteroid sample ever received on Earth.”
This should help “improve our understanding of asteroids that could hit the Earth”, as well as “the origin of our solar system”, he stressed.
The sample, taken in 2020 from the asteroid Bennu, must contain around 250 grams of material, according to the American space agency’s estimate, much more than the two previous asteroid samples reported by Japanese missions.
The capsule was wrapped and then placed in a net, which was lifted by a helicopter and taken to a temporary “clean room.”
The challenge was to expose the capsule for as short a time as possible to the sand of the American desert, in order to avoid any contamination of the sample which could distort subsequent analyses.
The target area on the ground for the landing was 58 km long by 14 km wide, on a military zone usually used to test missiles.
About four hours before landing, the Osiris-Rex probe released the capsule containing the sample, more than 100,000 km from Earth. This probe then set off to visit another asteroid.
Two Japanese samples
“The return of this sample is truly historic,” NASA scientist Amy Simon told AFP before the landing. This is the “largest sample we have brought back from lunar rocks” from the Apollo program, concluded in 1972.
On Monday, the sample will be flown to the Johnson Space Center in Houston, Texas. This is where the box will be opened, in another airtight room. The process will take days.
NASA is planning a press conference on October 11 to reveal initial results.
The majority of the sample will be preserved for study by future generations. About 25% will be immediately used for experiments, and a small part will be shared with partners Japan and Canada.
Japan itself gave NASA some grains from the asteroid Ryugu, of which it brought back 5.4 grams in 2020, during the Hayabusa-2 mission.
In 2010, he reported a microscopic amount from another asteroid.
This time, the Bennu sample is “much bigger, so we will be able to do a lot more analysis,” said Amy Simon.
History of our origin
Asteroids are composed of the original materials of the solar system, 4.5 billion years ago. Unlike Earth, they remained intact.
They therefore hold “clues about how the solar system formed and evolved,” Melissa Morris, head of the Osiris-Rex program at NASA, said at a press conference. “It is the story of our own origin.”
By hitting our planet, “we think that asteroids and comets brought organic matter, potentially water, that helped life develop on Earth,” explained Amy Simon.
Scientists believe that Bennu (500 meters in diameter) is rich in carbon, and contains water molecules locked in minerals.
The asteroid also surprised scientists: its surface turned out to be less dense than expected during sample collection.
The arm of the probe had sunk, a bit like in a ball pit.
However, better understanding its composition could prove useful in the future.
There is a small risk (1 chance in 2,700) that Bennu will hit Earth in 2182, a collision that would be catastrophic. But last year NASA managed to deflect the trajectory of an asteroid by hitting it.
09/24/2023 9:11:30 p.m. – Dugway (United States) (AFP) – © 2023 AFP
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2023-09-24 17:04:00
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