2023-10-11 12:29:57
NASA is due to reveal on Wednesday the first images of the largest asteroid sample ever collected in space, as well as the first analyzes of its composition, eagerly awaited by scientists around the world.
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The Osiris-Rex mission took this sample in 2020 from the asteroid Bennu, and the capsule containing the precious cargo successfully returned to Earth a little over two weeks ago, landing in the American desert.
Since then, the meticulous process of opening the capsule has taken place in a white room at NASA’s Johnson Space Center in Houston. And the operation has already reserved some surprises.
“There is so much material that it is taking us longer than expected to recover it,” said Christopher Snead, a scientist at NASA. But this is “the best problem we can have,” he added in a press release.
Before the capsule landed, the US space agency estimated it had succeeded in picking up around 250 grams of material from the asteroid Bennu — much more than two previous Japanese missions to other asteroids.
NASA, for whom such a maneuver was a first, will have to confirm this estimate on Wednesday during a public event, then a press conference.
But the echoes so far might not be more positive.
Material was found “in abundance” even outside the collection compartment, explained Christopher Snead. “It’s truly spectacular.”
“Black dust”
The happy surprise can be explained by an incident that occurred when the sample was collected: just following the operation, NASA realized that the flap of the collection compartment was unable to close.
The cargo had managed to be secured by being transferred as planned into the capsule, but because of this leak, scientists expected that residue would be found outside the compartment, in the box where it had been place.
This “black dust” and this “debris”, in the words of NASA, were entrusted to a rapid analysis team, in order to obtain a first idea of the composition of Bennu.
The sample is screened using a scanning electron microscope, x-ray diffraction, and infrared measurements.
This should make it possible to obtain an inventory of the minerals observed, and perhaps to determine their proportion. In particular, scientists believe that Bennu contains hydrated minerals.
The study of asteroids should allow scientists to better understand the formation of the solar system and how the Earth became habitable.
Asteroids like Bennu might have brought to Earth the compounds that subsequently allowed the birth of life, some scientists believe.
The majority of the sample will be preserved to be studied by future generations, with new, more efficient instruments and to answer new scientific questions. This is what was done for the lunar rocks brought back during the Apollo program.
Bennu’s analysis might also prove useful in the future. There is a small chance (1 in 2,700 chance) that the asteroid will hit Earth in 2182, a collision that would be catastrophic.
Knowing its exact composition might thus help, if necessary one day, to calculate the impact necessary to deviate its trajectory.
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