Seven years after its takeoff, the Osiris-Rex probe accomplished its mission: to deliver to humanity a “treasure”, the largest asteroid sample ever collected in space, and the first by NASA.
The capsule containing the sample, taken in 2020 from the asteroid Bennu, 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, had to be slowed by two successive parachutes. NASA has not confirmed whether the first worked, but the second deployed successfully, allowing for a smooth landing.
“We heard the main parachute deployed, and I burst into tears,” Dante Lauretta, scientific manager of the mission, told a press conference. “That’s the moment I knew we made it home.”
“For me, the science is only just beginning,” added the researcher.
The sample contains about 250 grams of material, according to the US space agency’s estimate — far more than the two previous asteroid samples reported by Japanese missions.
The analysis of Bennu should allow us to better understand the formation of the solar system, and how the Earth became habitable.
After landing, a team first analyzed the capsule on the ground to ensure its condition. No breach was noted.
She was then wrapped and 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 and 14 km wide, on a military base 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.
“The return of this sample is truly historic,” NASA scientist Amy Simon told AFP this week. This is the “largest sample we have brought back from lunar rocks” from the Apollo program, concluded in 1972.
On Monday, the precious package will be flown to the Johnson Space Center in Houston, Texas. This is where the box will be opened, in another airtight room.
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 percent will be immediately used for experiments, and a small portion 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, Bennu’s sample is much larger, so more analyzes will be possible.
It is “a treasure for scientific analysis, for years to come, for our children and our grandchildren, and people who have not even been born yet,” said Lori Glaze, director of planetary sciences. at NASA.
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 to how the solar system was formed.
Scientists believe that Bennu (500 meters in diameter) is rich in carbon, and contains water molecules locked in minerals.
“The main objective for me (…) is to try to understand if these carbon-rich asteroids like Bennu brought the compounds that could have led to the birth of life on our planet,” said Dante Lauretta.
During the mission, the asteroid already 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.
09/25/2023 01:30:06 – Dugway (United States) (AFP) – ©2023 AFP
