Nasa is in final preparations to launch the world’s first planetary defence mission. The Double Asteroid Redirection Test (Dart) is scheduled to launch on 23 November and is a joint mission with the Johns Hopkins Applied Physics Laboratory.
Dart is designed to collide with the asteroid Dimorphos and change its orbit as a test for spotting an asteroid on collision course with Earth and deflecting its path.
At 160 metres across, Dimorphos is about the size of the Great Pyramid of Giza. It is a moon to the larger asteroid Didymos and completes an orbit of its parent rock once every 11.9 hours.
In October 2022, Dart will collide with Dimorphos at a speed of 6.6 km/s. This will change the asteroid’s velocity by about 0.4 mm/s, altering its orbital period by about 10 minutes.
If imparted early enough, small changes to an Earth-heading asteroid could be enough to avoid catastrophe.
Dart is part of a larger, two-part mission called the Asteroid Impact and Deflection Assessment (Aida) mission. The second part is the European Space Agency’s Hera mission. Scheduled for launch in October 2024, Hera will study the aftermath of the collision in closeup.
Dart will be launched from Vandenberg space force base, California, on a SpaceX Falcon 9 rocket.
