Strictly speaking, a satellite collision is when two
satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition is typically loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit. Prime examples are the
anti-satellite weapon tests. There have been no observed collisions between
natural satellites, but impact craters may show evidence of such events. Both intentional and unintentional collisions have occurred between
man-made satellites around Earth since the 1980s.
Anti-satellite weapon tests and failed rendezvous or docking operations can result in orbital
space debris, which in turn may collide with other satellites.
Natural-satellite collisions
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.
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:
Several tests conducted as part of the
Soviet Union's
Istrebitel Sputnikov programme in the 1970s and 80s, involving IS-A satellites intercepting and destroying IS-P,
DS-P1-M and Lira target satellites launched specifically for the tests.
The 1985 destruction of the USA
P78-1 solar research satellite during a USA
ASM-135 anti-satellite missile test.
The 2008 destruction of the
USA-193 military reconnaissance satellite in a
decaying orbit by a USA
SM-3 missile.
The
2019 destruction of
Microsat-R after Indian military launched an anti-satellite weapon (ASAT) to destroy an Indian telecom satellite in a move called "Mission Shakti".
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 1991 collision between Kosmos 1934 and Mission-related debris (1977-062C, 13475).[1]
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 18 March 2021 collision between
Yunhai-1 02 and debris from the
Zenit-2 rocket body that launched the Kosmos 2333 satellite (a
Tselina-2 satellite) in 1996.[3]
There have been no spacecraft collisions with the
Martian moons.
There have been no spacecraft collisions with any
Jovian moons. Note that to avoid collision with
Europa and possible contamination by Earth microbes, the
NASAGalileo spacecraft was intentionally deorbited into Jupiter's atmosphere on September 21, 2003.
There have been no spacecraft collisions with any
Saturnian moons; the
ESAHuygens probe made a controlled landing on
Titan on January 14, 2005.
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.[4]