First it hit an asteroid. Now the frenzy of a NASA spacecraft can continue and it can shoot a hole in another space rock.
The OSIRIS-REX spacecraft is on its way back to Earth after hitting the surface of an asteroid called Bennu last year — briefly — to scoop up monsters. It will come home in 2023 and eject a capsule full of samples that could help eager scientists decipher the origins of water and life on Earth.
But the spacecraft still has plenty of fuel left. The mission team wondered: Could it go elsewhere?
Yes, it turns out. And not just anywhere, but one of the most famous asteroids near Earth: Apophis.
“We were pretty excited when we found out we could go there,” said Michael Nolan of the University of Arizona, the chief of the science team on the mission, who presented findings this week at the American Geophysical Union’s fall meeting in New York. Orléans.
Apophis was once considered the asteroid that posed the greatest threat to Earth. After its discovery in 2004, astronomers estimated the chance of hitting our planet in 2029 at one in 37, the highest in recorded history for an asteroid. At 300 meters across, it would not end life on our planet if it struck, but would decimate an area hundreds of kilometers wide.
“It was very scary,” said Dr. nolan.
Updated analysis later showed that the asteroid, which dances around Earth’s orbit, would have no impact on our planet. But it will still come close in April 2029 at a distance of just 20,000 miles, within the orbits of some geostationary satellites, and close enough to be visible to the naked eye in Europe, Asia and Africa.
If mission controllers on Earth sent OSIRIS-REX to complete three orbits of the planet after dropping its monsters, it could accidentally reach Apophis. When the asteroid flies through our skies, OSIRIS-REX would be just an hour behind, ready to slide upwards in June 2029.
“It’s kind of a fluke,” Dr. Nolan said.
While Apophis poses no threat to Earth — at least for the next century or so — studying it could tell us a lot about asteroids of this size. Currently, no other mission is planned to visit Apophis in 2029, although there are proposals to do so.
Next month, the OSIRIS-REX team will submit its proposal to NASA to extend the mission, with a decision expected in April. If it goes through, the spacecraft will spend 18 months studying Apophis after arrival.
While orbiting Apophis, OSIRIS-REX would plunge down the surface to capture high-resolution images. This includes looking for evidence of landslides caused by Earth’s gravity as the asteroid flew past.
The spacecraft would also attempt to descend to the surface and use its thrusters to blast a hole in the surface. The goal would be to uncover underground material, to help determine what the asteroid is made of.
“Apophis compositionally is the kind of asteroid most likely to become a hazard,” said Dr. nolan. “The material properties will help us understand what the structure is.”
This, in turn, could inform a future mission to save Earth from Apophis or another asteroid. By working out its mass, density and structure, scientists will know how spongy or hard the asteroid is, and tell us how best to interact with similar objects.
“We really need to understand what we’re dealing with,” said Jim Bell, an astronomer at Arizona State University who is not involved in the OSIRIS-REX mission. “Is this a solid chunk of stone? Can we change the orbit of this thing? Could we destroy it, blow it up into small pieces, if we had to take drastic measures?”
NASA’s ongoing DART mission, launched last month, conducts a not-too-dissimilar experiment by crashing into a small asteroid to see if we can alter its orbit.
Davide Farnocchia, of NASA’s Center for Near Earth Object Studies at the Jet Propulsion Laboratory in California, said Apophis’ close pass was a “great opportunity” to observe an asteroid of this size up close. It would also lead to a better understanding of whether Apophis poses a future threat to Earth.
After Apophis, OSIRIS-REX may even have enough fuel to visit yet another asteroid. Or it could be placed on the surface of Apophis and act as a “tracking beacon,” said Dr. nolan.
Budget constraints or other issues, such as concerns that OSIRIS-REX could inadvertently alter Apophis’ orbit and pose a threat to Earth, could determine whether the extended mission is approved. But it could be an exciting next chapter for the mission.
“It’s once in a millennium that something so big comes to Earth,” said Dr. bell. “We have to take advantage of that.”