in space exploration, the rendezvous and coupling of spacecraft or sections of spacecraft. Docking is a necessary operation in establishing space stations and in performing other missions with vehicles that function in orbit for prolonged periods, as well as in rescuing spacecraft crews. It may be executed manually (by the astronauts) or automatically. The first manual docking was achieved on Mar. 16, 1966, when the crew of the American spacecraft Gemini 8 docked with an Agena rocket. The first automatic docking took place on Oct. 30, 1967, between the Soviet artificial earth satellites Cosmos 186 and Cosmos 188.
The docking gear provides for the initial contact of the spacecraft, absorption of the collision energy, alignment of the spacecraft, locked coupling until a pressurized seal is obtained, and un-docking. Docking gear may be of the probe-and-cone type, in which the active docking device (the probe) is mounted on one spacecraft and the passive device (the cone) is mounted on the other, or it may have a two-way configuration that enables either spacecraft to perform active or passive docking. Probe-and-cone gear was used for docking of the Soviet spacecraft Soyuz 4 and Soyuz 5, the Soyuz 11 spacecraft and the Salyut space station, and American spacecraft in the Apollo program. Two-way docking gear was first tested in the Soyuz-Apollo program.