Explained: Why NASA crashed a spacecraft into an asteroid using kinetic impact?

Washington, Sep 27: After 10 months flying in space, NASA's Double Asteroid Redirection Test (DART) - the world's first planetary defense technology demonstration - successfully smashed its asteroid target using kinetic impact on Monday, 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 p.m. EDT.

It is just one way to defend planet Earth from an approaching object -and for now, the only method possible with current technology.

As a part of NASA's overall planetary defense 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.

"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."

What is the Nasa Dart mission?

The acronym stands for Double Asteroid Redirection Test, the first "planetary defense" experiment conducted by the US space agency, in association with scientists at Johns Hopkins University, to see if it can alter the trajectory of an asteroid in deep space if one ever comes close enough to threaten Earth.

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

Why NASA crashed a spacecraft into an asteroid?

Nasa wants to know if it has the capability to protect us if such a scenario ever occurs. This mission by NASA is nothing less than a full-scale planetary defence to change an asteroid's path. This technique is called kinetic impact, which will alter the orbit of the asteroid by crashing into it. This tiny deflection could be sufficient to prove that this technique can actually change the path of an asteroid on a collision path with the Earth. The spacecraft will be blown apart through impact equivalent to about three tonnes of TNT.

Kinetic impact

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.

Kinetic impaction involves sending one or more large, high-speed spacecraft into the path of an approaching near-earth object. This could deflect the asteroid into a different trajectory, steering it away from the Earth's orbital path.

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%, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

Future missions:

Roughly four years from now, the European Space Agency's Hera project will conduct detailed surveys of both Dimorphos and Didymos, with a particular focus on the crater left by DART's collision and a precise measurement of Dimorphos' mass.

The exploration of asteroids will not end here. It is reported that the European Space Agency is set to launch the Hera mission in 2024.

By observing the deformation caused by the arrow impact on Demorphos, the Hera spacecraft will reportedly gain a better understanding of its composition and formation.

It is anticipated that the lessons learned from this mission will help validate the mechanics of high-velocity collisions.