NASA DART Mission To Crash Into Asteroid Could One Day Save Earth From Killer Asteroids

NASA announced this week that it has approved a 2022 space mission, DART, that will test the idea that an impactor can crash into an asteroid and alter its course. Given that any asteroid approaching 100 meters (328 feet) in diameter could cause catastrophic regional damage to the Earth if it actually impacted, the data gathered by the test mission could potentially one day save the planet.

NASA announced on June 30 that the Double Asteroid Redirection Test (DART) was upgraded from concept development to preliminary design phase last week (June 23). The primary goal of the mission, according to Lindley Johnson, planetary defense officer at NASA Headquarters in Washington, is to test and gather data from the intentional crashing of a spacecraft into an asteroid.

"DART would be NASA's first mission to demonstrate what's known as the kinetic impactor technique -- striking the asteroid to shift its orbit -- to defend against a potential future asteroid impact."
Johnson added, "This approval step advances the project toward an historic test with a non-threatening small asteroid."

NASA's target for DART is a binary asteroid named Didymos (Greek for "twin") that will pass closest to Earth in October 2022 (and again in 2024). Didymos A, is roughly one-half mile (780 meters) in diameter and is orbited by a smaller asteroid called Didymos B, which measures about 530 feet (160 meters) in size. DART is designed to impact only the smaller asteroid, Didymos B.

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

"The fact that Didymos B 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."
asteroid pair in space
NASA's DART mission will send a spacecraft impactor into the smaller of two asteroids in a binary, Didymos B, to test an alteration of the smaller asteroid's orbit. [Image by Nostalgia for Infinity/Shutterstock]

The NASA approval for designing the DART spacecraft, which is tentatively estimated to be the size of a refrigerator, comes just a week after NASA announced that it was quietly phasing out another redirect mission called ARM (Asteroid Redirect Mission). The space agency stated, according to Space News, that congressional disinterest killed funding for the mission and financing was not made available in the latest budget blueprint released by the White House for fiscal year 2018.

ARM, which was first introduced in 2013, was to launch a robotic spacecraft to a near-Earth asteroid, where said craft would then obtain a boulder a few meters in diameter from the asteroid's surface. It would be designed to return the acquired boulder to cislunar space, where astronauts on an Orion spacecraft would then visit the orbiting boulder, performing studies and collecting samples for return to Earth.

Congress found that the asteroid mission was not critical to NASA's long-term goal of sending a manned mission to Mars.

imminent asteroid impactor
Can Earth be defended from an asteroid impact by a spacecraft designed to defelcet it? NASA's DART plans to test the idea's effectiveness in 2022. [Image by sdecoret/Shutterstock]

As for DART, it is designed to approach and impact Didymos B at a velocity of nine times the speed of a bullet (approximately 3.7 miles per second, or 6 kilometers per second). Observatories on Earth will monitor the impact and the resulting alteration in the orbit of Didymos B around Didymos A. This will allow scientists to more accurately determine the capabilities of the kinetic impact as an asteroid mitigation strategy, according to NASA. As explained by the space agency, "The kinetic impact 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."

[Featured Image by Jan Kaliciak/Shutterstock]