(This animation shows how NASA’s Double Asteroid Redirection Test (DART) would target and strike the smaller (left) element of the binary asteroid Didymos to demonstrate how a kinetic impact could potentially redirect an asteroid as part of the agency’s planetary defense program. Credits: NASA/JHUAPL.)

“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,” NASA planetary defense officer Lindley Johnson said in a statement. “This approval step advances the project toward an historic test with a non-threatening small asteroid.”

For DART, NASA wants to target the Didymos asteroid body, a twin system that is expected to make a distant approach near Earth in 2022 and 2024. The body consists of asteroid Didymos A, around 780 meters in size, and Didymos B, which is around 160 meters wide. According to NASA, DART wants to target only Didymos B.

As part of DART, the craft would fly towards Didymos and use an on-board targeting system to launch itself at Didymos B at a speed of around 3.7 miles per second. From the test, NASA wants to see how effective DART could be at preventing future larger asteroids. NASA believes that while the impact would only affect the velocity of the asteroid by a small margin, doing this early enough could alter its trajectory enough when it gets closer to Earth.

I think the first time it ever occurred to me that you might need to deflect an asteroid heading straight for your planet was in 1968 - thanks, Star Trek!

SPOCK: This obelisk is one huge deflector mechanism. It is imperative that we get inside immediately. Captain, we do not have much time.
KIRK: I don't know how to get inside.
SPOCK: If we are not able to gain entry and activate the deflector mechanism within the next fifty minutes, this entire planet will be destroyed.
KIRK: The key must be in these symbols. We've got to decipher them!

Spoiler! Spock presses the middle button of a row of three, and other sections light up. A blue beam shoots out of the top of the obelisk and pushes the asteroid away. Hopefully, NASA will also succeed with this program.