Currently on its way back to Earth with rock samples from the asteroid Bennu in its luggage, the OSIRIS-REx probe will play extra time. NASA has just extended its mission to visit another asteroid named Apophis.
On October 21, 2021, the American probe OSIRIS-REx landed on the asteroid Bennu more than 330 million kilometers from Earth. On site, the probe collected more than sixty grams of sample. His goal now is to bring them back to Earth. If all goes as planned, his return is scheduled for September 2023. The material, virtually unchanged for 4.6 billion years, will then be studied by scientists in laboratories around the world.
The original plan was that after jettisoning its capsule, the probe would then fly off to a graveyard orbit of the Sun, somewhere between Mercury and Venus. Finally, it will not be the end of the journey.
A few months ago, the mission team pointed out that OSIRIS-REX has enough fuel to visit another potential target: the asteroid Apophis. The team therefore submitted its proposal to NASA. After several months of study, the project has finally validated by the agency in consultation with theUniversity of Arizona. The new mission phase will be known as OSIRIS-Apophis Explorer or OSIRIS-APEX.
An Ancient Threat
Apophis (340 meters in diameter) was once considered a threat to Earth. Following its discovery in 2004, astronomers had indeed assessed its chance of hitting our planet in 2029 at 1 in 37. Follow-up analyzes had then tempered the spirits, underlining that the object would not hit the Earth during the hundred coming years.
Although Apophis poses no threat to Earth in the short to medium term, its study could tell us a lot about asteroids of this size.
That said, the asteroid will still pass from near Earth in April 2029 to just over 32 000 km distance. It is at this precise moment that the OSIRIS-REX probe could intervene after having carried out three flybys of the Earth.
In detail, the ship will make its first maneuver towards Apophis thirty days after dropping its sample capsule. Once there, he will study the asteroid for about eighteen months. During this mission, it will also be a question of firing the thrusters near the surface of the object to raise a little dust and expose underground material. In this way, scientists will be able to learn more about the composition of the asteroid. The team also plans to study the effects that Earth’s gravitational pull might have on the object as it passes by.
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