Salyut 4

Salyut 4 (DOS-4)

Salyut 4 being constructed
The insignia of the Salyut Program.
Station statistics
COSPAR ID	1974-104A
SATCAT no.	07591
Call sign	Salyut 4
Crew	2
Launch	December 26, 1974 04:15:00 UTC
Launch pad	LC-81/24, Baikonur Cosmodrome, Soviet Union
Reentry	February 3, 1977
Mass	18,210 kilograms (40,150 lb) (fuelled mass) 16,210 kilograms (35,740 lb)
Length	15.8 m
Width	4.15 m
Pressurised volume	90 m3
Periapsis altitude	136 mi (219 km)
Apoapsis altitude	168 mi (270 km)
Orbital inclination	51.6 degrees
Orbital period	89.1 minutes
Days in orbit	770 days
Days occupied	92 days
No. of orbits	12,444
Distance travelled	~313,651,190 mi (~504,772,660 km)
Statistics as of de-orbit and reentry
Configuration
Salyut 4 and Soyuz diagram

Salyut 4 (DOS 4) (Russian: Салют-4; English translation: Salute 4) was a Salyut space station launched on December 26, 1974 into an orbit with an apogee of 355 km, a perigee of 343 km and an orbital inclination of 51.6 degrees. It was essentially a copy of the DOS 3 (or Kosmos 557), and unlike its ill-fated sibling it was a complete success. Three crews attempted to make stays aboard Salyut 4 (Soyuz 17 and Soyuz 18 docked; Soyuz 18a suffered a launch abort). The second stay was for 63 days duration, and an unmanned capsule, called Soyuz 20, remained docked to the station for three months, proving the system's long-term durability despite some deterioration of the environmental system during Soyuz 18's mission. Salyut 4 was deorbited February 2, 1977, and re-entered the Earth's atmosphere on February 3.