Double Asteroid Redirection Test (DART) was a NASA space mission aimed at testing a method of planetary defense against near-Earth objects (NEOs). It was designed to assess how much a spacecraft impact deflects an asteroid through its transfer of momentum when hitting the asteroid head-on. The selected target asteroid, Dimorphos, is a minor-planet moon of the asteroid Didymos; neither asteroid poses an impact threat to Earth. Launched from Earth on 24 November 2021, the DART spacecraft successfully collided with Dimorphos on 26 September 2022 and shortened its orbit by 32 minutes, greatly in excess of the pre-defined success threshold of 73 seconds. DART is a joint project between NASA and the Johns Hopkins Applied Physics Laboratory. The project was funded through NASA's Planetary Defense Coordination Office, managed by NASA's Planetary Missions Program Office at the Marshall Space Flight Center, and several NASA laboratories and offices provided technical support. The Italian Space Agency contributed LICIACube, a CubeSat which photographed the impact event, and other international partners, such as the European Space Agency (ESA), and Japan Aerospace Exploration Agency (JAXA), are contributing to related or subsequent projects. Mission history NASA and the European Space Agency (ESA) started with individual plans for missions to test asteroid deflection strategies, but by 2015, they struck a collaboration called AIDA (Asteroid Impact and Deflection Assessment) involving two separate spacecraft launches that would work in synergy. Under that proposal, the European spacecraft, AIM, would have launched in December 2020, and DART in July 2021. AIM would have orbited the larger asteroid to study its composition and that of its moon. DART would then kinetically impact the asteroid's moon on 26 September 2022, during a close approach to Earth. The AIM orbiter was however canceled, then replaced by Hera which plans to start observing the asteroid four years after the DART impact. Live monitoring of the DART impact thus had to be obtained from ground-based telescopes and radar. In June 2017, NASA approved a move from concept development to the preliminary design phase, and in August 2018 the start of the final design and assembly phase of the mission. On 11 April 2019, NASA announced that a SpaceX Falcon 9 would be used to launch DART. Satellite impact on a small solar system body had already been implemented once, by NASA's Deep Impact space probe's impactor spacecraft and for a completely different purpose (analysis of the structure and