A major catastrophic asteroid impact is just a matter of time, and NASA is gearing up to tackle such potentially hazardous asteroids. The Double Asteroid Redirection Test (DART) mission has moved from the concept stage to a design stage, and will test the viability of using a spacecraft to deflect an asteroid that can strike Earth. The approach will use what is known as the kinetic impactor technique, where a spacecraft manages to change the trajectory of an asteroid just enough so that it is no longer a problem to humans on Earth.
In 2022 and 2024, a pair of asteroids will fly past the Earth at a safe distance. The two asteroids are together called Didymos, the Greek word for "twin". Didymos B is smaller than Didymos A, and the target of the DART mission. Tom Statler, program scientist for DART says "A binary asteroid is the perfect natural laboratory for this test. 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."
Didymos B is about 160 meters in diameter, and is the size of an asteroid that could have regional effects if it struck Earth. DART is a refrigerator sized spacecraft that will use on board systems aim at the target asteroid, and strike it at speeds that are nine times that of a bullet. If successful, the technology proven by the DART mission can be used to prevent a catastrophic asteroid strike on the surface of Earth.