NASA is about to make history once again. Next month, the OSIRIS-REx probe should indeed make its very first attempt to sample the asteroid Bennu. Back on Earth, these extraterrestrial materials can shed light on the history of the Solar System.
It's almost the big day! Four years after its launch from Cape Canaveral, Florida, the American probe OSIRIS-REX is preparing to do what it was built for:collect a sample of the asteroid Bennu (500 meters in diameter). NASA has announced that the maneuver should normally take place on October 20.
"I can't tell you how excited I am", said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona during a press conference on Thursday (September 24). “I am convinced that we are up to the challenge ahead “.
Indeed, the maneuver will be far from easy. The size of a small van, the probe will indeed have to descend in a spiral towards a small crater nicknamed Nightingale, aiming for a relatively flat region of only eight meters wide .
For your information, the target is narrower than expected. Indeed, NASA had initially anticipated a landing zone of about fifty meters. Nevertheless, Bennu's surface appeared much rougher than ground observations had suggested.
This operation, OSIRIS-REx will also have to manage it on its own (or almost). More than 200 million kilometers distance, it will take more than eighteen minutes signals to travel from Earth to the spacecraft. Controlling the maneuver in real time will therefore be impossible for mission operators.
Once there, OSIRIS-REx won't stay stationary for long. The probe will kiss the ground with its 3.4 m long sampling arm, for only a few seconds. A small explosion of nitrogen gas will then lift some material which will then be sucked up to be collected.
Ideally, NASA would like to collect sixty grams of it . If the quantity of material is deemed insufficient, a second attempt could be scheduled at the beginning of next year on another site.
These samples will then be sealed. If all goes as planned, OSIRIS-REx will leave Bennu in March 2021 and return to Earth on September 24, 2023 . The capsule should normally land in the desert of Utah, United States.
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 will 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 will not be the first probe to bring pristine asteroid samples back to Earth. The Japanese spacecraft Hayabusa has already delivered some grains from the asteroid Itokawa in 2010. The samples from the asteroid Ryugu, captured by the Japanese probe Hayabusa2, should land in Australia on December 6th.> .
