Mission accomplished. The spacecraft sent by NASA to divert the trajectory of an asteroid hit its target on Monday, as part of a novel “planetary defense” test that should better protect humanity from an eventual devastating collision with a cosmic object.
The ship, smaller than a car, crashed at more than 20,000 kilometers per hour against its target, which it reached at the scheduled time, 23:14 GMT.
And NASA teams, gathered at mission control in Maryland, burst with happiness at the spectacular images of the approaching asteroid Dimorphos until shortly before impact.
In the live broadcast, rocks could be clearly distinguished on the gray surface of the asteroid located about 11 million kilometers from Earth.
“We are embarking on a new era, where we potentially have the ability to protect ourselves from a dangerous asteroid impact,” said Lori Glaze, NASA’s director of planetary sciences.
Dimorphos measures about 160 meters in diameter and does not represent any danger to our planet. It is actually the satellite of another larger asteroid, Didymos, around which it orbited in 11 hours and 55 minutes. NASA was looking to reduce its orbit by about 10 minutes to bring it closer to Didymos.
It will take several days or perhaps weeks for scientists to confirm that the asteroid’s trajectory really changed, and they will do so thanks to telescopes on Earth that will observe the change in brightness when the small asteroid passes in front of or behind the large one.
Although the objective is still modest compared to that of science fiction films such as “Armageddon”, this “planetary defense” mission baptized as DART (Double Asteroid Redirection Test) allows NASA to train in the event that a large asteroid threatens a day with impacting the Earth.
integrated camera
The ship traveled for ten months from its takeoff in California.
To hit such a small target, it steered autonomously for the last four hours of the journey, like a self-guided missile.
Three minutes after the impact, a satellite the size of a shoebox, called LICIACube and launched by DART a few days ago, was to pass within 55 km of the asteroid to capture images of the collision, which will be sent to Earth in the next weeks and months.
The event was also to be observed by the Hubble and James Webb Space Telescopes, which should be able to detect a bright cloud of dust.
All this will also serve to better understand the composition of Dimorphos, which is representative of a fairly common population of asteroids, and therefore measure the effect that this technique, called kinetic impact, can have on them.
unknown
Asteroids have surprised scientists in the past.
In 2020, the American Osiris-Rex probe sank much deeper than expected to the surface of the asteroid Bennu.
The porosity of Dimorphos is currently unknown. “If the asteroid responds to the DART impact in a completely unexpected way, it might actually lead us to reconsider the extent to which kinetic impact is a generalizable technique,” Statler said.
None of the known asteroids threaten Earth for the next 100 years.
Nearly 30,000 asteroids of all sizes have been cataloged in its vicinity, which it calls near-Earth objects, that is, its orbit crosses the Earth’s orbit.
Those of a kilometer or more have been sighted almost all, according to scientists. But they estimate that they only know about 40% of the asteroids that measure 140 meters or more, capable of devastating an entire region.
“Our most important job is to find” the missing ones, said Lindley Johnson, NASA’s planetary defense agent.
The earlier they are detected, the more time experts have to determine the best way to defend against them.
But the DART mission is a crucial first step, Johnson said: “It’s a very exciting time … in space history, and even in human history.”
“I think Earthlings can sleep better, I definitely will,” said DART mission systems engineer Elena Adams.