Despite its playful name, taken from Miguel de Cervantes´s classic novel, the European Space Agency´s Don Quijote mission is deadly serious. Slated for 2012, the $180-million mission will attempt to move one of two target asteroids, just identified this fall, by rear-ending it with a speeding spacecraft. Quijote is the first venture of its kind, although the B612 Foundation, a privately-funded nonprofit based in Tiburon, California, intends to launch a similar effort by 2015.