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.
![]() Salyut 4 being constructed | |
![]() Salyut 4 diagram | |
![]() The insignia of the Salyut Program. | |
Station statistics | |
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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 |
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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 represented the second phase of DOS civilian space station. Although the basic design of Salyut 1 was retained, it switched to three large solar panels mounted on the forward module rather than its predecessor's four small panels on the docking module and engine compartment, presumably to generate more power. It had an interior floor area of 34.8 sq. m The pitch of the station was 2 X 59 N, yaw was 2 X 59 N and roll was 2 X 20 N. The electric System produced an average of 2.00 kW of power. It had 2,000 kg of scientific equipment alongside two sets of three solar panels each and was equipped with the Delta Navigation System which was a new autonomous navigation system that calculates orbital elements without assistance from ground.[1] It was powered by KTDU-66 thrusters.[2]
Installed on the Salyut 4 were OST-1 (Orbiting Solar Telescope) 25 cm solar telescope with a focal length of 2.5m and spectrograph shortwave diffraction spectrometer for far ultraviolet emissions, designed at the Crimean Astrophysical Observatory, and two X-ray telescopes.[3][4] One of the X-ray telescopes, 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 in × 10 in 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).[1]
Other instruments include a swivel chair for vestibular function tests, lower body negative pressure gear for cardiovascular studies, bicycle ergometer integrated physical trainer (electrically driven running track 1 m X .3 m with elastic cords providing 50 kg load), penguin suits and alternate athletic suit, sensors for temperature and characteristics of upper atmosphere, ITS-K infrared telescope spectrometer and ultraviolet spectrometer for study of earth's infrared radiation, multispectral earth resources camera, cosmic ray detector, embryological studies, new engineering instruments tested for orientation of station by celestial objects and in darkness and a teletypewriter.[1]
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.
Expedition | Crew | Launch date | Flight up | Landing date | Flight down | Duration (days) | Notes |
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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 | Launch from Baikonur; landing 110 km northeast of Tselinograd; docking on space station Salyut 4, which had been launched 3 days earlier; transfer into space station and 29 days stay time there; astronomical experiments. |
Soyuz 18 | Pyotr Klimuk, Vitaly Sevastyanov |
May 24, 1975 14:58:10 UTC |
Soyuz 18 | July 26, 1975 14:18:18 UTC |
Soyuz 18 | 62.97 | Launch from Baikonur; landing 56 km east of Arkalyk; 2. crew of spacestation Salyut 4; 62 days staying time; intensive fitness training; breeding of "space vegetable"; solar observation; taking photographs of Earth surface. |
Salyut programme | ||
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Salyut stations (DOS) | ![]() | |
Almaz stations (OPS) |
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TKS spacecraft |
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List of space stations | |||||||||
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Notes: † Never inhabited due to launch or on-orbit failure, ‡ Part of the Almaz military program, ° Never inhabited, lacks docking mechanism. |
← 1973 · Orbital launches in 1974 · 1975 → | |
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Kosmos 628 | Skynet 2A | Kosmos 629 | Kosmos 630 | Kosmos 631 | Sphinx · VDS | Kosmos 632 | OPS 6889 | Tansei 2 | San Marco 4 | Kosmos 633 | Meteor-M No.30 | Kosmos 634 | Miranda | Kosmos 635 · Nauka-17KS No.1L | OPS 8579 | Kosmos 636 | Kosmos 637 | Kosmos 638 | Kosmos 639 | OPS 6245 · OPS 4547 · OPS 3935 | Kosmos 640 | Unnamed | Westar 1 | Molniya-1-27 | Kosmos 641 · Kosmos 642 · Kosmos 643 · Kosmos 644 · Kosmos 645 · Kosmos 646 · Kosmos 647 · Kosmos 648 | Meteor-M No.22 | Molniya-2-9 | Kosmos 649 | Kosmos 650 | Kosmos 651 | Kosmos 652 | Kosmos 653 | Kosmos 654 | SMS-1 | Interkosmos 11 | Kosmos 655 | Yantar-2K No.1 | Kosmos 656 | Luna 22 | Kosmos 657 | ATS-6 | Explorer 52 | Kosmos 658 | OPS 1776 | Kosmos 659 | Kosmos 660 | Kosmos 661 | Salyut 3 | Kosmos 662 | Kosmos 663 | Kosmos 664 | Kosmos 665 | Soyuz 14 | Meteor-Priroda No.1 | DS-P1-Yu No.68 | Kosmos 666 | Unnamed | OPS 7518 | Aeros 2 | Molniya-2-10 | Kosmos 667 | Kosmos 668 | Kosmos 669 · Nauka-8KS No.3 | Molniya-1 No.38 | Kosmos 670 | Kosmos 671 | OPS 6983 | Kosmos 672 | OPS 3004 | Kosmos 673 | Soyuz 15 | Kosmos 674 | Kosmos 675 | Unnamed | ANS | Kosmos 676 | Kosmos 677 · Kosmos 678 · Kosmos 679 · Kosmos 680 · Kosmos 681 · Kosmos 682 · Kosmos 683 · Kosmos 684 | Kosmos 685 | Kosmos 686 | Westar 2 | Kosmos 687 | Ariel 5 | Kosmos 688 | Kosmos 689 | Kosmos 690 | Molniya-1 No.26 | Kosmos 691 | Meteor-M No.33 | Luna 23 | OPS 7122 · OPS 6239 · OPS 8452 | Interkosmos 12 | Kosmos 692 | Kosmos 693 | Fanhui Shi Weixing 1 | NOAA-4 · OSCAR-7 · INTASAT | Kosmos 694 | Kosmos 695 | Molniya-3 No.11 | Intelsat IV F-8 | Skynet 2B | Kosmos 696 | Soyuz 16 | Helios 1 | Kosmos 697 | Meteor-M No.32 | Kosmos 698 | Symphonie 1 | Molniya-2-11 | Kosmos 699 | Salyut 4 | Kosmos 700 | Kosmos 701 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |