There have been no observed collisions between natural satellites of any Solar System planet or moon. Collision candidates for past events are:
- Impact craters on many Jupiter (Jovian) and Saturn's (Saturnian) moons. They may have been formed by collisions with smaller moons, but they could equally likely have been formed by impacts with asteroids and comets during the Late Heavy Bombardment.
- The far side of the Moon may have formed from the impact of a smaller moon that also formed during the giant impact event that created the Moon.
- The objects making up the Rings of Saturn are believed to continually collide and aggregate with each other, leading to debris with limited size constrained to a thin plane. Although this is believed to be an ongoing process, this has not been directly observed.
Three types of collisions have occurred involving artificial satellites orbiting the Earth:
- Intentional collisions intended to destroy the satellites, either to test anti-satellite weapons or destroy satellites which may pose a hazard should they reenter the atmosphere intact:
- Unintentional low-speed collisions during failed rendezvous and docking operations:
- The 1994 collision between the crewed Soyuz TM-17 spacecraft and the Russian Mir space station.
- The 1997 low-speed collision between the Progress M-34 supply ship and the Russian Mir space station during manual docking manoeuvers.
- The 2005 low-speed collision between the USA DART spacecraft and the USA MUBLCOM communications satellite during orbital rendezvous manoeuvers.
- Unintentional high-speed collisions between active satellites and orbital debris:
- The 1996 collision between the French Cerise military reconnaissance satellite and debris from an Ariane rocket.
- The 2009 collision between the Iridium 33 communications satellite and the derelict Russian Kosmos 2251 spacecraft, which resulted in the destruction of both satellites.
- The 22 January 2013 collision between debris from Fengyun FY-1C satellite and the Russian BLITS nano-satellite.
- The 22 May 2013 collision between two CubeSats, Ecuador's NEE-01 Pegaso and Argentina's CubeBug-1, and the particles of a debris cloud around a Tsyklon-3 upper stage (SCN 15890) left over from the launch of Kosmos 1666.
- The 18 March 2021 collision between Yunhai-1 02 and debris from the Zenit-2 rocket body that launched Tselina-2 in 1996.
Satellite collision avoidance
Satellite operators frequently maneuver their satellites to avoid potential collisions. One notable near collision was Sept 2019 between an ESA satellite and a SpaceX Starlink satellite, when ESA tweeted/complained at having to move to avoid the Starlink satellite.