A Don Quijote spacecraft flying by the Earth

Detail of a Don Quijote spacecraft trajectory from the Earth to the asteroid.
Don Quijote is currently under study by ESA’s Advanced Concepts Team (ACT). Two target asteroids (2002 AT4 and 1989 ML) have been selected.
The current scenario envisages two spacecraft in separate interplanetary trajectories. One spacecraft (Hidalgo) will impact an asteroid; the other (Sancho) will arrive earlier at the target asteroid, rendezvous and orbit the asteroid for several months, observing it before and after the impact to detect any changes in its orbit.