The largest asteroid sample ever collected, and the first by NASA, landed this Sunday, September 24, 2023, in the American desert of Utah and after a dizzying descent through the Earth’s atmosphere, seven years after the takeoff of the Osiris-Rex probe.
The fall, which was observed by military sensors, was stopped by two parachutes. The sample, taken in 2020 from the asteroid Bennu, contains about 250 grams of material, according to estimates by the US space agency, more than two previous asteroid samples collected by Japanese missions.
This material “will help to better understand the types of asteroids that can threaten the Earth” and shed light on “the beginning of the history of the solar system,” emphasized the head of the space agency, Bill Nelson.
This is the “biggest sample we’ve gotten from lunar rocks” since the Apollo program, which ended in 1972, NASA scientist Amy Simon told AFP before landing.
Approximately four hours before its scheduled landing time, the Osiris-Rex probe released the capsule containing the sample, more than 100,000 kilometers from Earth.
During the last 13 minutes, this capsule passed through the atmosphere: it entered at more than 44,000 km/h and reached a temperature of 2,700°C. The probe continues its mission to another asteroid.
Two Japanese samples
When the capsule reached the ground, a team with gloves and masks checked its condition before placing it in a net and lifting it into a helicopter. The capsule should be exposed to the desert sand for as short a time as possible to avoid any contamination of the sample that could distort subsequent analyses.
This Monday, the sample will be sent to the Johnson Space Center in Houston, Texas. There the box opens to another airtight chamber. The process takes days.
NASA plans a press conference on October 11 to reveal the initial results. Most of the sample will be preserved for the study of future generations. About 25% will be used immediately for experiments and a small part will be shared with partners in Japan and Canada.
Japan gave NASA fragments of the Ryugu asteroid, of which 5.4 grams were recovered in 2020, during the Hayabusa-2 mission. In 2010, he reported a microscopic amount of another asteroid. The Bennu sample “is bigger, so we can do a lot of analysis,” Simon said.
History of our origin
Asteroids are composed of the original materials of the solar system, which, unlike Earth, remain intact. It contains “clues about how the solar system formed and evolved,” explained Melissa Morris, director of NASA’s Osiris-Rex program. “This is the story of our own origins.”
By crashing into our planet, “we think that asteroids and comets brought organic matter, possibly water, that helped develop life on Earth,” Simon said.
Scientists believe that Bennu (500 meters in diameter) is rich in carbon and contains water molecules wrapped in minerals.
The surface of the asteroid turned out to be less dense than expected. A better understanding of its composition will be useful in the future. There is a small risk (one chance in 2,700) that Bennu will hit Earth in 2182, which would be catastrophic.
In 2022, NASA managed to divert the trajectory of an asteroid by impacting it.