The Guardian reports:

In a few weeks, Nasa controllers will deliberately crash their $330m Dart robot spacecraft into an asteroid. The half-tonne probe will be travelling at more than four miles a second when it strikes its target, Dimorphos, and will be destroyed.

The aim of this kamikaze science mission is straightforward: space engineers want to learn how to deflect asteroids in case one is ever discovered on a collision course with Earth. Observations of Dart’s impact on Dimorphos’s orbit will provide crucial data about how well spacecraft can protect Earth from asteroid armageddon, they say.

“We know asteroids have hit us in the past,” said Professor Alan Fitzsimmons, an astronomer at Queen’s University Belfast. “These impacts are a natural process and they are going to happen in the future. We would like to stop the worst of them.

“The problem is that we have never tested the technology which will be needed to do that. That is the purpose of Dart,” said Fitzsimmons, a member of the science team for the Double Asteroid Redirection Test (Dart) mission. Launched last November, the probe is scheduled to strike its target in the early hours of 27 September, BST. By carefully studying the asteroid’s path after the collision, scientists believe they will better understand how similar collisions could be used to deflect Earth-bound asteroids and comets. [Continue reading…]