The OSIRIS-REx probe has successfully landed on the asteroid Bennu in an attempt to harvest some material. It will nevertheless be necessary to wait a few days before being able to confirm the capture of the samples. If so, these extraterrestrial materials may shed some light on the history of the Solar System.
NASA did it! Four years after its launch from Cape Canaveral, Florida, the American probe OSIRIS-REX made its first attempt to sample the asteroid Bennu (500 meters in diameter) this night at 00:13 (French time), at more than 330 million kilometers from Earth .
The ship spiraled down before "kissing" the asteroid's surface for approximately ten seconds, deploying its sample-taking mechanism attached to the tip of a 3.4 meter long robotic arm. The probe, the size of a small van, was aimed at a small crater dubbed Nightingale, a relatively flat region only eight meters wide.
Mission leaders monitored the maneuver from the Lockheed Martin Space Operations Center in Littleton, Colorado. “Transcendent! I can't believe we made it" , said Dante Lauretta, mission manager, during NASA's live broadcast of the operation. “The spacecraft did everything it was supposed to do” .
At more than 300 million kilometers away, it took more than eighteen minutes for the signals to travel from Earth to the ship. Controlling the maneuver in real time was therefore impossible for the mission operators. So the probe had to "manage itself".
During this brief landing, the ship blew up some nitrogen gas on the surface of Bennu in an attempt to kick up some rock and dust, which was then collected by the arm sampling head.
On the other hand, it will be necessary to wait about ten days before being able to determine whether the probe has picked up enough material. The goal was to get at least sixty grams . If the "bag" is a bit light, NASA has advised that two more attempts could still be scheduled if needed.
If all goes as planned, OSIRIS-REx should normally leave Bennu in March 2021 before returning to Earth on September 24, 2023 to drop off his "parcel" in the desert of Utah, USA.
The material will then be analyzed by scientists around the world. Formed around 4.5 billion years ago, Bennu is an almost unchanged relic of our solar system. Studying it with state-of-the-art instrumentation can thus give us an insight into the formation of our system. These samples could also contain the molecular precursors that may have led to the evolution of life on Earth.
Note that OSIRIS-REx is not the first probe to perform such a maneuver. The Japanese probe Hayabusa2 indeed landed on the asteroid Ryugu twice in 2019 (in February and July). The collected samples should land in Australia on December 6th.
