Nasa’s Double Asteroid Redirection Test (DART) – the world’s first planetary defence technology demonstration – successfully impacted its asteroid target, the agency’s first attempt to move an asteroid in space.

Mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, announced the successful impact at 7.14 pm local time on Monday.

As a part of Nasa’s overall planetary defence strategy, DART’s impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered, Nasa said.

‘Unprecedented success for planetary defense’

“At its core, DART represents an unprecedented success for planetary defense, but it is also a mission of unity with a real benefit for all humanity,” said Nasa Administrator Bill Nelson.

“As Nasa studies the cosmos and our home planet, we’re also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth.”

DART targeted the asteroid moonlet Dimorphos, a small body just 530 feet (160 metres) in diameter. It orbits a larger, 2,560-foot (780-metre) asteroid called Didymos. Neither asteroid poses a threat to Earth.

The mission’s one-way trip confirmed Nasa can successfully navigate a spacecraft to intentionally collide with an asteroid to deflect it, a technique known as kinetic impact.

Asteroid monitoring

The investigation team will now observe Dimorphos using ground-based telescopes to confirm that DART’s impact altered the asteroid’s orbit around Didymos. Researchers expect the impact to shorten Dimorphos’ orbit by about 1 per cent, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

“Planetary Defense is a globally unifying effort that affects everyone living on Earth,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at Nasa headquarters in Washington.

“Now we know we can aim a spacecraft with the precision needed to impact even a small body in space. Just a small change in its speed is all we need to make a significant difference in the path an asteroid travels.”

Image: Asteroid Didymos (top left) and its moonlet, Dimorphos, about 2.5 minutes before the impact of NASA’s DART spacecraft. The image was taken by the on board DRACO imager from a distance of 570 miles (920 kilometres). This image was the last to contain a complete view of both asteroids. Didymos is roughly 2,500 feet (780 meters) in diameter; Dimorphos is about 525 feet (160 metres) in length. Didymos’ and Dimorphos’ north is toward the top of the image. Credits: NASA/Johns Hopkins APL
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