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NASA plans to protect Earth from a future killer asteroid strike

NASA plans to change a space rock's orbit by crashing a refrigerator-sized spacecraft into it

IANS  |  Washington 

Generic image of an asteroid near Earth's orbit
Generic image of an asteroid near Earth

Aiming to show how to protect from a future killer strike, National Aeronautics and Space Administration (NASA) plans to crash a refrigerator-sized spacecraft at a speed about nine times faster than a bullet into a space rock, forcing it to change its orbit.

The target for the first-ever mission to demonstrate an deflection technique for planetary defence — the Double Redirection Test (DART) — is an asteroid that will have a distant approach to in October 2022, and then again in 2024, said.

"would be NASA's first mission to demonstrate what's known as the — striking the asteroid to shift its orbit — to defend against a potential future asteroid impact," said Lindley Johnson, planetary defence officer at Headquarters in Washington.

The asteroid is called — Greek for "twin" — because it is an asteroid binary system that consists of two bodies — A, about 780 metres in size, and a smaller asteroid orbiting it called B, about 160 metres in size.

DART, scheduled for launch in 2020, would impact only the smaller of the two bodies,

The Didymos system has been closely studied since 2003. The primary body is a rocky S-type object, with composition similar to that of many asteroids.

The composition of its small companion, Didymos B, is unknown, but the size is typical of asteroids that could potentially create regional effects should they impact

"A binary asteroid is the perfect natural laboratory for this test," said Tom Statler, programme scientist for at Headquarters.

"The fact that is in orbit around Didymos A makes it easier to see the results of the impact, and ensures that the experiment doesn't change the orbit of the pair around the sun," Statler added.

After launch, would fly to Didymos, and use an on-board autonomous targeting system to aim itself at

Then the spacecraft would strike the smaller body at a speed about nine times faster than a bullet, approximately six kilometres per second.

Earth-based observatories would be able to see the impact and the resulting change in the orbit of Didymos B around Didymos A, allowing scientists to better determine the capabilities of as an asteroid mitigation strategy.

The technique works by changing the speed of a threatening asteroid by a small fraction of its total velocity, but by doing it well before the predicted impact so that this small nudge will add up over time to a big shift of the asteroid's path away from Earth.

"DART is a critical step in demonstrating we can protect our planet from a future asteroid impact," said Andy Cheng of The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, the DART investigation co-lead.

First Published: Mon, July 10 2017. 03:21 IST