Don Quijote (spacecraft)
|Operator||European Space Agency|
|Mission type||Orbiter, Impactor, and Lander|
|Flyby of||2003 SM84
or 99942 Apophis
|Homepage||Sancho study (ESA)|
Don Quijote is a proposed space probe under development by the European Space Agency, which would study the effects of crashing a spacecraft into an asteroid. The mission is intended to test whether a spacecraft could successfully deflect an asteroid on a collision course with Earth. The orbiter is being designed to last for seven years.
The mission is still in the planning stages with launch dates proposed for 2013 or 2015.
The mission will consist of two spacecraft that will execute a series of maneuvers around a small, 500-metre (1,600-foot) asteroid.
- The first spacecraft, Sancho, will arrive at the asteroid and orbit it for several months, studying it. The orbiter will use a single xenon ion engine.
- After a few months, the second spacecraft, Hidalgo, will hurtle toward the asteroid on a collision course. It will sleep for most of the trip and then steer itself using optical sensors with an accuracy of 50 meters. Sancho will retreat to a safe distance while Hidalgo will hit the asteroid at around 10 km/s.
- Sancho will then return to its close orbit and see how much the asteroid's shape, internal structure, orbit and rotation have been affected by the impact.
- Sancho will release the Autonomous Surface Package, a Lander which will free-fall toward the asteroid for 2 hours before landing. This package will be directed towards the interior of the impact crater where it will investigate properties of the surface.
The craft would be launched by a Vega launcher and a Star 48 upper stage. The ESA is currently considering two design scenarios: the "Cheap Option" using a chemical propulsion system and the "Flexible Option" using an electric propulsion system. The former would be targeted to the Amor asteroid 2003 SM84, the latter to the asteroid 99942 Apophis.
Sancho (orbiter) 
The instruments on the orbiter are classified into those essential to the success of the mission and those for the completion of extended mission objectives. The primary instruments are the Radio Science Experiment, Orbiter Camera, Imaging Laser Altimeter, and a LIDAR instrument. For the extended mission objectives, the orbiter carries an IR Spectrometer, a Thermal IR Imager, an X-Ray Spectrometer, a Radiation Monitor and the Autonomous Surface Package (ASP).
Hidalgo (impactor) 
Unlike many other spacecraft, the goal of the Hidalgo impactor is to be as massive as possible upon reaching the target asteroid; because of this goal, the propulsion module is not jettisoned after use. The impactor carries few subsystems to make it as low-cost and maneuverable as possible. It has no moving appendages (solar panels, etc.) to complicate orientation, it uses only its RCS thrusters for course corrections, and it has a high-resolution targeting camera for ~50 m targeting accuracy on impact. The LISA Pathfinder design was considered as an initial design reference.
Originally, the ESA identified two near-Earth asteroids as possible targets: 2002 AT4 and (10302) 1989 ML. Neither asteroid represents a threat to Earth. In a subsequent study, two different possibilities were selected: the Amor asteroid 2003 SM84 and 99942 Apophis; the latter is of particular significance to Earth as it will make a close approach in 2029 and 2036.
In 2005, the proposed mission was combined with AIDA, with the target selected as a binary asteroid, so that the effect of the deflection can be seen even from Earth by observing the period of the binary. The targets were 2002 AT4 and (10302) 1989 ML
The mission is named after the fictional Spanish knight from Miguel de Cervantes' renowned novel, Don Quixote, who charged against a windmill, thinking it to be a giant. Like Quixote, the Hidalgo spacecraft will 'attack' an object much larger than itself, hopefully with more impressive results. 'Sancho' is named after Sancho Panza, the Quixote's squire, who preferred to stay back and watch from a safe distance, which is the role assigned to that probe. Finally, the name Hidalgo was a minor Spanish title (roughly equivalent to a Baronet), now obsolete. In the novel, it was the title Alonso Quijano had even before becoming Don Quijote.
See also 
- "Don Quixote concept". ESA.
- "Sancho study: designing the minimum Earth escape spacecraft". ESA. August 18, 2011.
- ESA selects targes for asteroid deflecting mission Don Quijote
-  Asteroid Impact Deflection Assessment AIDA study (ESA), 19 December 2012
- Asteroid deflection mission seeks smashing ideas (ESA), 15 January 2013
- Asteroid Deflection Mission AIDA Set To Crash Two Spacecraft Into Space Rock In 2022 Huffington Post
Further reading 
- Gil-Fernández, J.; Panzeca, R.; and Corral, C. (2008-10-15). "Impacting small Near Earth Objects". Advances in Space Research 42 (8): 1352. Bibcode:2008AdSpR..42.1352G. doi:10.1016/j.asr.2008.02.023.