Salyut 4

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**Salyut 4**
Mission Insignia

Salyut 4

Mission Statistics
Mission name:	Salyut 4
Call sign:	Salyut 4
Launch:	December 26, 1974 04:15:00 UTC Baikonur, U.S.S.R
Reentry:	February 3, 1977
Crews:	2
Occupied:	92 days
In orbit:	770 days
Number of orbits:	12,444
Apogee:	168 mi (270 km)
Perigee:	136 mi (219 km)
Period:	89.1 min
Inclination	51.6 deg
Distance traveled:	~313,651,190 mi (~504,772,660 km)
Orbital mass:	18,500 kg
Salyut 4

Salyut 4 (DOS 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, 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 Soyuz capsule remained docked to the station for three months, proving the system's long-term durability. Salyut 4 was deorbited on February 3, 1977.

[edit] Instrumentation

The Salyut 4 X-ray instrument, often called the Filin telescope, consisted of four gas flow proportional counters, three of which had a total detection surface of 450 cm² in the energy range 2-10 keV, and one of which had an effective surface of 37 cm² for the range 0.2 to 2 keV (32 to 320 aJ). The field of view was limited by a slit collimator to 3° × 10° full width at half maximum. The instrumentation also included optical sensors which were mounted on the outside of the station together with the X-ray detectors, and power supply and measurement units which were inside the station. Ground based calibration of the detectors was considered along with in-flight operation in three modes: inertial orientation, orbital orientation, and survey. Data could be collected in 4 energy channels: 2 to 3.1 keV (320 to 497 aJ), 3.1 to 5.9 keV (497 to 945 aJ), 5.9 to 9.6 keV (945 to 1,538 aJ), and 2 to 9.6 keV (320 to 1,538 aJ) in the larger detectors. The smaller detector had discriminator levels set at 0.2 keV (32 aJ), 0.55 keV (88 aJ), and 0.95 keV (152 aJ).

[edit] Science

Among others, observations of Sco X-1, Cir X-1, Cyg X-1, and A0620-00 were published from the Filin data. A highly variable low energy of 0.6 to 0.9 keV (96 to 144 aJ) flux was detected in Sco X-1. Cir X-1 was not detected at all during a July 5 1975 observation, providing an upper limit on the emission of 3.5e-11 erg·cm^-2·s^-1 (35 fW/m²) in the 0.2 to 2.0 keV (32 to 320 aJ) range. Cyg X-1 was observed on several occasions. Highly variable flux, in both the time and energy domains, was observed.

[edit] Specifications

Length - 15.8 m
Maximum diameter - 4.15 m
Habitable volume - 90 m³
Weight at launch - 18,900 kg
Launch vehicle - Proton (three-stage)
Orbital inclination - 51.6°
Area of solar arrays - 60 m²
Number of solar arrays - 3
Electricity production - 4 kW
Resupply carriers - Soyuz Ferry
Number of docking ports - 1
Total manned missions - 3
Total unmanned missions - 1
Total long-duration manned missions - 2

[edit] Visiting spacecraft and crews

Soyuz 17 - January 11 - February 10, 1975
- Georgi Grechko
- Aleksei Gubarev

Soyuz 18a - April 5, 1975 - Launch abort
- Vasili Lazarev
- Oleg Makarov

Soyuz 18 - May 24 - July 26, 1975
- Pyotr Klimuk
- Vitali Sevastyanov

Soyuz 20 - November 17, 1975 - February 16, 1976
- no crew

[edit] Salyut 4 Expeditions

Expedition	Crew	Launch Date	Flight Up	Landing Date	Flight Down	Duration - Days -
Soyuz 17	Georgi Grechko, Aleksei Gubarev	January 11, 1975 21:43:37 UTC	Soyuz 17	February 10, 1975 11:03:22 UTC	Soyuz 17	29.56
Soyuz 18	Pyotr Klimuk, Vitali Sevastyanov	May 24, 1975 14:58:10 UTC	Soyuz 18	July 26, 1975 14:18:18 UTC	Soyuz 18	62.97