The US probe Osiris Rex definitively left the orbit of the asteroid Bennu, from which it collected dust samples last year, on Monday to begin its journey back to Earth.
There’s still a long way to go: It won’t land in the U.S.A.’s Utah Desert until September 24, 2023.
In a video broadcast of the event by NASA, Dante Loretta, the mission chief, said the probe is “now moving at a speed of more than 950 km / h from Benno, on its way home.”
The impellers of the machine were operated without incident for seven minutes in order to implement the thrust necessary to put the probe on the right track. The latter will cross Earth’s expedition after a final trip of 2.3 billion kilometers.
Osiris-Rex returns “more than 60 grams” of dust and asteroid fragments on board, the largest sample that NASA has collected from lunar rocks brought back by the Apollo missions.
To achieve this result, the US Space Agency carried out a high-risk operation in October 2020: the probe touched the Earth of the asteroid for a few seconds, and the dust was lifted by the explosion of the nitrogen disk before it was captured.
Surprise: The arm of the probe sank several centimeters into the surface of the asteroid, which scientists knew was actually “very sub-formed,” said Dante Loretta.
Almost everything failed when NASA realized a few days later that the collecting compartment flap was failing to close, allowing shrapnel to escape into space.
But it finally ended up securing the charge, as it was moved from the sensor arm to the center capsule.
In two and a half years, this capsule will be dropped a few hours before it enters Earth’s atmosphere, and its speed will be slowed by the parachute system for its descent.
The agency said that the samples will then be transported to NASA’s Johnson Space Center in Houston, but 75% will remain intact “to be studied by future generations using technologies that have not yet been established.”
Their analysis should help scientists better understand the formation of the solar system and the evolution of Earth as a habitable planet.