ESA selects targets for asteroid-deflecting mission Don Quijote   Artist's impression of the Don Quijote Mission. A near miss?     Artist's impression on an asteroid impact with the Earth. Looking for the perfect target     Comparative sizes of asteroids.   This artist's impression shows how the families of asteroids follow the orbits of their prototypes. Amors cross Mars’ orbit but do not cross Earth’s. It is the Apollo asteroids that cross Earth’s orbit. There are also the Atens. These asteroids spend most of their time inside Earth’s orbit, crossing it briefly before disappearing back into the glare of the Sun. Note for editors:     Hidalgo impacts with the asteroid while Sancho, with an attitude appropriate to its name, retreats to a safe distance to observe the impact without taking unnecessary risk.