THE SALYUT FAMILY

Salyut 1: (1971) Also known as DOS 1. First Earth orbiting space station; occupied 23 days.
Salyut: (1972) Also known as DOS 2. Suffered launch failure 29-Jul-1972.
Salyut 2: (1973) Also known as Almaz 1. Suffered a systems failure while in orbit.
Cosmos 557: (1973) Also known as DOS 3. Suffered a systems failure while in orbit.
Salyut 3: (1974) Also known as Almaz 2. Second USSR space station. Introduced uprated solar arrays. Operated 7 months; occupied 15 days.
Salyut 4: (1974) Also known as DOS 4. Third USSR space station; occupied 93 days.
Salyut 5: (1976) Also known as Almaz 3. Fourth USSR space station; occupied 65 days.
Salyut 6: (1977) Also known as DOS 5. Fifth USSR space station. Incorporated uprated propulsion system and rear docking port. Orbited for almost 5 years; occupied 676 days.
Salyut 7: (1982) Sixth USSR space station. Orbited for almost 9 years; occupied 812 days.

Salyut development began in the 1960s and it became clear to western observers as the program developed that there were distinct civil and military interests. It was not until a 1990s publication that details were revealed publically of how separate they were. Chelomei's bureau had been working since 1964 on the manned Almaz military station when Korolev's bureau was directed in late 1969 to produce a station (designated DOS: 'Permanent Orbital Station') within 18 months. The first meeting between the bureaus took place Feb-1970. The Korolev bureau took over two Almaz vessels. They remained separate programs, although they both used Chelomei's 3-stage Proton. A slightly different history, however, claims that Almaz was almost completed by Chelomei but the control system was late. The program was forced on Korolev in 1970 and the bureau added Soyuz elements (particularly the control system, solar panels and propulsion unit) to create Salyut.

Salyut 7 had three habitable compartments totalling 100 m³. From Salyut 6 a major redesign of the original engine system replaced the single nozzle with twin nozzles on each side of the second docking port added at the rear. >20 portholes were provided for experiments, visual observations and photography. The work was conducted from seven control posts.

The Forward Transfer Compartment, 2 m diameter x 3 m long, was basically an access tunnel with an inner bulkhead enabling it to be sealed off for EVAs from the side hatch; two suits stored here were for the shared use of all visiting crews. There were seven portholes, some carrying astro-orientation sensors.

The Working/Operations Compartment was the main living/working area and was comprised of two cylindrical shells connected by a conical section. The small first section was 2.9 m diamter x 3.5 m long, the conical section 1.2 m long, and the second section 4.15 m diameter x 2.7 m long. Equipment was arranged in standard racks around the interior's sides. Salyut's central control position in the lower part of the first section had two seats. Further back, a table offered hot food and hot/cold water. On one side was the system that regenerated water from the atmosphere, and on the other the onboard computer. In the rear of the larger section, on opposite sides, were the crew's bunks and food stowage. Aft was a toilet and two small airlocks for ejecting waste. The shower was at the forward end of the section. To the outside of the first section were attached three solar panels, two horizontal and one vertical, spanning 17 m. (On Salyut 1-2 there were two smaller pairs of horizontal panels, with the Soyuz providing supplementary power from a similar pair.)

The Rear Transfer Compartment was first incorporated on Salyut 6. On early Salyuts this was an unpressurized service module 2.2 m diameter x 2.17 m long. On Salyut 6 it was widened to the same 4.15 m diameter as the working compartment to take a second docking port. Here the short-term Intercosmos visitors were received when they docked, as were the unmanned Progress ferries, which plugged into the propellant resupply lines.

SALYUT 1 SPECIFICATIONS

Designation: DOS 1
Launched: 19-Apr-1971
Reentered: 11-Oct-1971
Principal uses: civilian space station
Orbit: 200 x 222 km, 51.6^o
Crew size: 3; occupied 23 days by 1 crew (Soyuz pressure loss killed crew before reentry)
Overall length: 13.1 m
Maximum diameter: 4.15 m
Total mass: 18,210 kg
Propellant mass: 2,000 kg
Propulsion system
    main engine thrust: 4.09 kN (+ 4.03 kN backup)
    propellant: nitric acid/UDMH
    specific impulse: 282 s
    delta v: 320 m/s
Attitude & orbit control system
    thrusters: 14 (+4 backup) x 98 N + 18 X 9.8 N
    propellant: hydrogen peroxide
Power: 4 solar panels, each 9.8 m span, 33 m² total area; 1.0 kW average

SALYUT 3 SPECIFICATIONS

Designation: Almaz 2
Launched: 25-Jun-1974
Reentered: 24-Jan-1975
Principal uses: military space station
Orbit: ? x 219 km
Crew size: 2; occupied 15 days by 1 crew
Power: three solar arrays, automatically rotating through 180^o for tracking the Sun, instead of the four fixed small arrays on Salyut 1

SALYUT 4 SPECIFICATIONS

Designation: DOS 4
Launched: 26-Dec-1974
Reentered: 3-Feb-1977
Principal uses: civilian space station
Orbit: initially 219 x 270 km, 51.6^o; raised to 343 x 355 km
Crew size: typically 2; occupied 93 days by 2 crews
Overall length: 13.1 m
Maximum diameter: 4.15 m
Total mass: 18,900 kg
Propellant mass: 2,000 kg
Propulsion system
    main engine thrust: 4.09 kN (+ 4.03 kN backup)
    propellant: nitric acid/UDMH
    specific impulse: 282 s
    delta v: 320 m/s
Attitude & orbit control system
    thrusters: 4 (+4 backup) x 98 N + 4 x 59 N + 2 x 20 N + 18 X 9.8 N
    propellant: hydrogen peroxide
Power: 3 solar panels, each 17.0 m span, 60 m² total area; 2.0 kW average

SALYUT 5 SPECIFICATIONS

Designation: Almaz 3
Launched: 22-Jun-1976
Reentered: 8-Aug-1977
Principal uses: military space station
Orbit: initially 219 x 260 km, 51.6^o; raised to 256 x 275 km
Crew size: typically 2; occupied 65 days by 2 crews
Total mass: 19,000 kg?

SALYUT 6 SPECIFICATIONS

Designation: DOS 5
Launched: 29-Sep-1977
Reentered: 28-Jul-1982
Principal uses: civilian space station
Orbit: initially 219 x 275 km, 51.6^o; raised to 355 x 377 km
Crew size: typically 2-3; occupied 676 days by 5 long stay + 11 visiting crews
Overall length: 14.4 m
Maximum diameter: 4.15 m
Habitable volume: 90 m³
Total mass: 19,825 kg
Propellant mass: 1,200 kg
Propulsion system
    main engine thrust: 2 x 2.94 kN
    propellant: NTO/UDMH
    specific impulse: 305 s
Attitude control thrusters: 14 x 98 N + 18 x 9.8 N
Power: 3 solar panels, each 17.0 m span, 60 m² total area; 2.0 kW average

SALYUT 7 SPECIFICATIONS

Launched: 19-Apr-1982
Reentered: 7-Feb-1991
Principal uses: civilian space station
Orbit: initially 212 x 260 km, 51.6^o; raised to 474 km circular
Crew size: typically 2-3; occupied 812 days by 10 crews
Overall length: 14.4 m
Maximum diameter: 4.15 m
Habitable volume: 100 m³
Total mass: 19,920 kg
Propellant mass: 1,200 kg
Propulsion system
    main engine thrust: 2 x 2.94 kN
    propellant: NTO/UDMH
    specific impulse: 305 s
Attitude control thrusters: 14 x 98 N + 18 x 9.8 N
Power: 3 solar panels, each 17.0 m span, 60 m² total area; 2.0 kW average