|Mission type||Asteroid probe|
|Operator||European Space Agency, NASA|
|Start of mission|
|Launch date||AIM (cancelled)
DART: July 2021 (proposed)
DART: Minotaur V
|(65803) Didymos  orbiter|
|Spacecraft component||AIM (cancelled)|
|Orbital insertion||October 2022 (cancelled)|
|(65803) Didymos impactor|
|Impact date||October 2022|
The Asteroid Impact and Deflection Assessment (AIDA) mission was a proposed pair of space probes which would study and demonstrate the kinetic effects of crashing an impactor spacecraft into an asteroid moon. The mission is intended to test whether a spacecraft could successfully deflect an asteroid on a collision course with Earth. The concept proposed two spacecraft: Asteroid Impact Mission (AIM) (built by ESA) would orbit the asteroid, and Double Asteroid Redirection Test (DART) (built by NASA) would impact its moon. Besides the observation of the change of orbital parameters of the asteroid moon, the observation of the plume, the crater, and the freshly exposed material will provide unique information for asteroid deflection, science and mining communities.
In December 2016 the European Space Agency cancelled the development of the AIM spacecraft after Germany decided to fund ExoMars project only. However, NASA will continue with the development of DART spacecraft and will monitor the effects of the impact with ground-based telescopes.
The AIDA mission was a joint international collaboration of the European Space Agency (ESA), the German Aerospace Center (DLR), Observatoire de la Côte d'Azur (OCA), NASA, and Johns Hopkins University Applied Physics Laboratory (JHU/APL). The project was formed by joining two separate studies, Applied Physics Laboratory, an asteroid impactor developed by NASA, and a monitoring spacecraft - ESA's AIM.
AIDA would have targeted 65803 Didymos, a binary asteroid system in which one asteroid is orbited by a smaller one. The primary asteroid is about 800 m (2,600 ft) in diameter; its small satellite is about 150 m (490 ft) in diameter in an orbit about 1.1 km from the primary. Didymos is not an Earth-crossing asteroid, and there is no possibility that the deflection experiment could create an impact hazard.
Under the proposal, AIM would have launched in October 2020, and DART in July 2021. AIM would have orbited the larger asteroid and study the composition of it and its moon. DART would then impact the moon on October 2022, during a close approach to Earth. AIM would have studied the asteroid's strength, surface physical properties and its internal structure, as well as measure the effect on the asteroid moon's orbit around the larger asteroid. Since the AIM orbiter was cancelled, the effects of the impact by DART will be monitored from ground-based telescopes.
The impact of the 300 kg (660 lb) DART spacecraft at 6.25 km/s will produce a velocity change on the order of 0.4 mm/s, which leads to a significant change in the mutual orbit of these two objects, but only a minimal change in the heliocentric orbit of the system. AIDA would have provided a great benefit obtaining the size of the resulting impact crater in addition to the momentum transfer measurement, as the effects of porosity and strength of the target are needed to calculate the momentum transfer efficiency.
DART is a 300 kg (660 lb) impactor that hosts no scientific payload other than a 20-cm aperture CCD camera to support autonomous guiding to impact the target body through its center.
- AIM (cancelled)
- an asteroid lander (based on the German MASCOT heritage) for in-situ measurements
- a thermal infrared imager to discriminate different surface properties like rocks or granular surfaces
- a monostatic high frequency radar to obtain information on the structure of the asteroid's surface
- a bistatic low frequency radar (on the orbiter and on the lander) that allows a view inside the asteroid and obtain data on its inner structure
- two interplanetary CubeSats  out of five proposals currently under investigation that support the science and technology objectives of the AIM and AIDA mission
- deep-space optical communication
Both AIM and DART were initially approved for preliminary design in February 2015, but in December 2016 the ESA component, the AIM orbiter was not funded in order to help pay for additional expenses of the ExoMars rover. ExoMars rover has been in development since at least 2005 when over half a billion Euros was authorized for it.
Germany offered to cover 35 million of the 60 million needed for the AIM portion to continue, however, this was not enough to continue development. Nevertheless, NASA will continue the DART mission to (65803) Didymos, and will measure the effects of the impact from ground-based telescopes. 
- Cheng, A.F.; Michel, P.; Reed, C.; Galvez, A.; Carnelli, I. (2012). DART: Double Asteroid Redirection Test (PDF). European Planetary Science Congress 2012. EPSC Abstracts.
- Asteroid Impact & Deflection Assessment (AIDA) study Archived 2015-06-07 at the Wayback Machine..
- "AIDA study". ESA. 19 December 2012. Archived from the original on 20 October 2014. Retrieved 2014-09-19.
- AIDA mission rationale Archived May 11, 2015, at the Wayback Machine.. ESA, 25 May 2012.
- ExoMars Rover Gets Funding Despite Schiaparelli Mars Lander Crash. Alixandra Caole Vila, Nature World News. 7 December 2016.
- NASA presses ahead with asteroid mission despite ESA funding decision. Jeff Foust, Space News. 13 December 2016
- "AIDA: Asteroid Impact and Deflection Assessment Mission Under Study at ESA and NASA" (PDF). Observatoire de la Côte d'Azur. February 2015. Retrieved 2015-03-29.
- Cubesat Companions for ESA's Astroid [sic] Mission. Source: ESA. November 2, 2015.
- Andone, Dakin (July 25, 2017). "NASA unveils plan to test asteroid defense technique". CNN. Retrieved July 25, 2017.
- Video: 5 min presentation of AIDA, at YouTube.