Don Quijote is an asteroid investigation , geophysical characterisation and deflection technological experiment mission. The mission will contain the following elements: * Two spacecraft which are to be launched in separate interplanetary trajectories. * One spacecraft, which will be referred to as Hidalgo, will impact an asteroid of approximately 500 m diameter at a relative speed of at least 10 km/s. * The other spacecraft, called Sancho, will arrive earlier at the same asteroid along a very different route, perform a rendez-vous and remain in orbit around the asteroid for several months before and after the impact. * Sancho will...