• NASA’s First Planetary Defense Technology Demonstration to Collide with Asteroid in 2022.
• The Double Asteroid Redirection Test, or DART, is a spacecraft designed to determine whether an asteroid can be redirected with a high-speed collision.
• SpaceX will launch the spacecraft toward an asteroid named Didymos about 4 million miles from Earth. It then will ram into the asteroid’s small moon at about 13,000 miles per hour.
• 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.

?About DART:

• The target for DART is an asteroid that will have a distant approach to Earth in October 2022, and then again in 2024.
• The asteroid is called Didymos – Greek for “twin” -because it is an asteroid binary system that consists of two bodies: Didymos A, about 780 metres in size, and a smaller asteroid orbiting it called Didymos B, about 160 metres in size.
• DART would impact only the smaller of the two bodies, Didymos B. 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 Earth. After launch, DART would fly to Didymos and use an APL-developed onboard autonomous targeting system to aim itself at Didymos B.
• Then the refrigerator-sized spacecraft would strike the smaller body at a speed about nine times faster than a bullet, about 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 kinetic impact as an asteroid mitigation strategy.
• 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.