Soyuz 18
| Mission type | Docking with Salyut 4 |
|---|---|
| Operator | Soviet space program |
| COSPAR ID | 1975-044A |
| SATCAT no. | 07818 |
| Mission duration | 62 days 23 hours 20 minutes 8 seconds |
| Orbits completed | 993 |
| Spacecraft properties | |
| Spacecraft | Soyuz 7K-T No.7 |
| Spacecraft type | Soyuz 7K-T |
| Manufacturer | NPO Energia |
| Launch mass | 6570 kg |
| Landing mass | 1200 kg |
| Crew | |
| Crew size | 2 |
| Members | Pyotr Klimuk Vitaly Sevastyanov |
| Callsign | Кавказ (Kavkaz - "Caucasus") |
| Start of mission | |
| Launch date | 24 May 1975, 14:58:10 UTC |
| Rocket | Soyuz-U |
| Launch site | Baikonur, Site 1/5 |
| End of mission | |
| Landing date | 26 July 1975, 14:18:18 UTC |
| Landing site | 56 km at the east of Arkalyk, Kazakhstan 51°N 68°E / 51°N 68°E |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Perigee altitude | 193.0 km |
| Apogee altitude | 247.0 km |
| Inclination | 51.6° |
| Period | 88.6 minutes |
| Docking with Salyut 4 | |
| Docking date | 26 May 1975 |
| Undocking date | 26 July 1975 |
| Time docked | 61 days |
Vimpel Diamond patch | |
Soyuz 18 (Russian: Союз 18, Union 18) was a 1975 Soviet crewed mission to Salyut 4, the second and final crew to man the space station. Pyotr Klimuk and Vitaly Sevastyanov set a new Soviet space endurance record of 63 days and the mark for most people in space simultaneously (seven) was tied during the mission.