The US space probe Osiris-Rex began its long trip back to Earth on Monday, leaving the orbit of the asteroid Bennu, from which it obtained dust samples last year.
The probe also has a long journey ahead of it until touching down in the Utah desert on September 24, 2023.
Osiris-Rex is “now moving away over 600 miles an hour from Bennu, on its way home,” mission commander Dante Lauretta said on NASA’s video broadcast of the incident.
The spacecraft’s thrusters were engaged without incident for seven minutes to put the probe on the correct trajectory home, a journey of 1.4 billion miles (2.3 billion kiometers).
It is carrying more than 60 grams of dust and fragments from the asteroid, the largest sample collected by NASA since the Moon rocks brought back by the Apollo missions.
To achieve this goal, the US space agency launched a high-risk operation in October 2020: the probe came into contact with the asteroid for a few seconds, and a blast of compressed nitrogen was emitted to raise the dust sample which was then captured.
The surprise for NASA was the probe’s arm sank several centimeters into the surface of the asteroid, showing the scientists that “the surfaces of these rubble pile asteroids are very loosely consolidated,” said Lauretta.
The whole mission almost came to nought when NASA realized a few days later that the valve of the collection compartment was failing to close, letting fragments escape into space.
But the precious cargo was finally secured after being transferred to a capsule fixed in the spacecraft’s center.
The capsule will be launched a few hours before entering the Earth’s atmosphere in two and a half years, and its landing will be slowed by a parachute device.
The samples will then be shipped to NASA’s Johnson Space Center in Houston, where 75 percent will be preserved for future generations to study with advanced technologies that have yet to be created, according to the agency.
The findings can aid scientists in their understanding of the origin of the solar system and the evolution of Earth as a habitable planet.