By Michelle Starr
The time has come. We’re going to smash a spacecraft into an asteroid.
The asteroid is Didymos B, the smaller of the two objects in the Didymos binary asteroid system. The spacecraft is NASA’s Double Asteroid Redirection Test (DART). The reason: to test whether a spacecraft impact can deflect an asteroid’s trajectory, as a means to protect Earth from rogue space rocks.
The joint asteroid impact and deflection assessment (AIDA) project by the European Space Agency (ESA) and NASA was announced in 2015, but recent surprise findings from subsequent asteroid missions may have implications for the test.
For example, when JAXA’s Hayabusa2 bombed asteroid Ryugu in April of this year, it made a much bigger crater than expected. In addition, the material on the asteroid’s surface behaves a lot like sand; that could influence the effectiveness of kinetic impact deflection.