The asteroid Bennu contains water and carbon as scientists hoped, NASA said Wednesday, revealing the first images of dust and blackened bits from the largest asteroid sample ever returned to Earth.
“Water and carbon molecules are exactly the kind of matter we wanted to find,” NASA boss Bill Nelson said at an event in Houston. “These are crucial elements in the formation of our own planet, and they will help us determine the origin of elements that could have led to life. »
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 clean room at NASA’s Johnson Space Center in Houston.
But the operation held some surprises.
Because of the abundance of material found outside the collection compartment itself, it has not yet begun to be opened, said Eileen Stansbery, chief scientist at the Johnson Space Center.
“We take our time to carry out treatment methodically, and take care of each piece of Bennu properly,” she explained.
Before the capsule landed, the American space agency estimated that it had succeeded in collecting 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 still have to confirm this estimate.
“Black Dust”
The happy surprise of this “bonus” material can be explained by an incident that occurred when the sample was collected: just after the operation, NASA realized that the valve in the collection compartment was not able to to reclose.
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 “debris,” in NASA’s words, was given to a rapid analysis team to get a first idea of Bennu’s composition.
The sample was screened using a scanning electron microscope, X-ray diffraction, and infrared measurements.
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 could 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 could also prove useful in the future. There is a small chance (1 in 2700 chance) that the asteroid will hit Earth in 2182, a collision that would be catastrophic.
Knowing its exact composition could thus help, if necessary one day, to calculate the impact necessary to deviate its trajectory.