View source for Salyut 1

{{short description|Soviet space station (1971)}}
{{Use American English|date=October 2019}}
{{Use mdy dates|date=April 2018}}
{{Infobox space station
 | spelling               = us
 | station                = Salyut 1 (DOS-1)
 | station_image          = Salyut 1.jpg
 | station_image_size     =
 | station_image_caption  = Salyut 1 as seen from the departing [[Soyuz 11]]
 | insignia               = Salyut_program_insignia.svg
 | insignia_size          = 160px
 | insignia_caption       =
 | COSPAR_ID              = <!-- Wikidata -->
 | SATCAT                 = <!-- Wikidata -->
 | sign                   = Salyut 1
 | crew                   = 3
 | launch                 = {{start-date|April 19, 1971, 01:40:00}}&nbsp;[[Coordinated Universal Time|UTC]]<ref name="Nasa 1971-032A"/>
 | carrier_rocket         =  [[Proton-K]] No.&nbsp;254-01
 | launch_pad             = [[Baikonur Cosmodrome|Baikonur]], [[Baikonur Cosmodrome Site 81|Site 81/24]]
 | reentry                = {{end-date|October 11, 1971}}
 | status                 = [[Atmospheric entry#Deorbit disposal|De-orbited]]
 | mass                   = {{cvt|18425|kg}}
 | length                 = ~{{cvt|20|m}}
 | diameter               = ~{{cvt|4|m}}
 | volume                 = {{cvt|99|m3}}
 | pressure               =
 | perigee                = {{cvt|200|km|mi nmi|0}}
 | apogee                 = {{cvt|222|km|mi nmi}}
 | inclination            = 51.6°
 | speed                  =
 | period                 = 88.5 minutes
 | orbits_day             =
 | in_orbit               = 175 days
 | occupied               = 24 days
 | orbits                 = 2,929
 | distance               = {{cvt|118602524|km}}
 | apsis                  = gee
 | as_of                  =
 | stats_ref              =
 | configuration_image    = RP1357 p64 Salyut 1.svg
 | configuration_size     =
 | configuration_caption  = Soyuz docking with Salyut 1
|configuration_class=skin-invert-image}}

'''Salyut 1''' ({{langx|ru|Салют-1||Salute 1}}), also known as '''DOS-1''' (Durable Orbital Station 1), was the world's first [[space station]]. It was launched into [[low Earth orbit]] by the [[Soviet Union]] on April 19, 1971. The [[Salyut programme|''Salyut'' program]] subsequently achieved five more successful launches of seven additional stations. The program's final module, [[Zvezda (ISS module)|''Zvezda'']] (DOS-8), became the core of the [[Russian Orbital Segment]] of the [[International Space Station]] and remains in orbit today.

Salyut 1 was adapted from an [[Almaz]] airframe and comprised five components: a transfer compartment, a main compartment, two auxiliary compartments, and the [[Orion (space telescope)|Orion 1 Space Observatory]]. It was visited by the [[Soyuz 10]] and [[Soyuz 11]] missions. While the crew of Soyuz 10 was able to soft dock, the [[Docking and berthing of spacecraft#Docking states|hard-docking]] failed, forcing the crew to abort their mission. The Soyuz 11 crew successfully docked, spending 23 days aboard Salyut 1 conducting experiments. The Soyuz 11 crew died of asphyxia caused by a valve failure just before reentry, making them the only humans to have died above the [[Kármán line]].

Following the deaths, the mission of Salyut 1 was terminated, and the station reentered Earth's atmosphere, burning up on October 11, 1971.

== Background ==
Salyut 1 originated as a modification of the Soviet military's [[Almaz]] space station program that was then in development.{{sfn|Portree|1995}} After the landing of [[Apollo 11]] on the Moon in July 1969, the Soviets began shifting the primary emphasis of their crewed space program to orbiting space stations, with a possible lunar landing later in the 1970s if the [[N1 (rocket)|N-1 rocket]] became flight-worthy.{{sfn|Baker|2007|p=18}} [[Leonid Brezhnev]] canceled the lunar landing program in 1974 after four catastrophic N-1 launch failures. One other motivation for the space station program was a desire to one-up the US [[Skylab]] program then in development. The basic structure of Salyut 1 was adapted from the Almaz with a few modifications and would form the basis of all Soviet space stations through [[Mir]].{{sfn|Portree|1995}}

Civilian Soviet space stations were internally referred to as DOS (Durable Orbital Station), although publicly, the Salyut name was used for the first six DOS stations (''[[Mir]]'' was internally known as DOS-7).{{sfn|Portree|1995}} Several military experiments were nonetheless carried on Salyut 1, including the OD-4 optical visual ranger,{{sfn|Ivanovich|2008|p=9}} the Orion ultraviolet instrument for characterizing rocket exhaust plumes,{{sfn|Ivanovich|2008|p=29}} and the highly classified Svinets [[radiometer]].<ref>{{cite web | url=http://www.jamesoberg.com/cosmonauts-see-launches.pdf | title=Have cosmonauts seen launches? | first=James | last=Oberg |author-link=James Oberg |page=4 |date=2016-12-18 |access-date=2018-04-18 |df=mdy-all}}</ref>{{self-published source|date=June 2022}}

== Construction and operational history ==
Construction of Salyut 1 began in early 1970, and after nearly a year it was shipped to the [[Baikonur Cosmodrome]]. Some remaining assembly had yet to be done, and this was completed at the launch center. The Salyut programme was managed by [[Kerim Kerimov]],<ref>{{cite book |url=https://books.google.com/books?id=V60oDwAAQBAJ&pg=PA85 |title=Outposts on the Frontier: A Fifty-Year History of Space Stations |publisher=[[University of Nebraska Press]] |first=Jay |last=Chladek |pages=85–86 |date=2017 |isbn=978-0-8032-2292-2}}</ref> chairman of the state commission for Soyuz missions.{{sfn|Ivanovich|2008|p=56}}

Launch was planned for April 12, 1971 to coincide with the 10th anniversary of [[Yuri Gagarin]]'s flight on [[Vostok 1]], but technical problems delayed it until April 19.<ref>{{Cite book |url=https://books.google.com/books?id=JIAgAQAAIAAJ&q=salyut+1+april+12+1971 |title=Into the Final Frontier: The Human Exploration of Space |last=McNamara |first=Bernard |publisher=Harcourt College Publishers |year=2001 |isbn=9780030320163 |pages=223 }}</ref> The first crew launched later in the [[Soyuz 10]] mission, but they ran into troubles while docking and were unable to enter the station; the Soyuz 10 mission was aborted and the crew returned safely to Earth. A replacement crew launched on [[Soyuz 11]] and remained on board for 23 days. This was the first time in the history of spaceflight that a space station had been occupied, and a new record was set for time spent in space. This success was, however, short-lived when the crew was killed during [[Atmospheric entry|reentry]], as a pressure-equalization valve in the Soyuz 11 reentry capsule had opened prematurely, causing the crew to asphyxiate. They were the first and, as of 2025, only humans to have died in space. After this accident, all missions were suspended while the Soyuz spacecraft was redesigned. The station was intentionally destroyed by [[Atmospheric re-entry|de-orbiting]] after six months in orbit, because it ran out of fuel before a redesigned Soyuz spacecraft could be launched to it.{{sfn|Shayler|Hall|2003|p=179}}

==Structure==
At launch, the announced purpose of Salyut was to test the elements of the systems of a space station and to conduct scientific research and experiments. The craft was described as being {{convert|20|m|ft|abbr=on}} in length, {{convert|4|m|ft|abbr=on}} in maximum diameter, and {{convert|99|m3|cuft|abbr=on}} in interior space with an on-orbit dry mass of {{convert|18425|kg|lb|abbr=on}}. Of its several compartments, three were pressurized (100&nbsp;m<sup>3</sup> total), and two could be entered by the crew.<ref name="Nasa 1971-032A"/>

===Transfer compartment===
The transfer compartment was equipped with the only [[docking and berthing of spacecraft|docking port]] of Salyut 1, which allowed one [[Soyuz 7K-OKS]] spacecraft to dock. It was the first use of the Soviet [[SSVP docking system]] that allowed internal crew transfer, a system that is in use today. The docking cone had a {{convert|2|m|ft|abbr=on}} front diameter and a {{convert|3|m|ft|abbr=on}} aft diameter.<ref name="Nasa 1971-032A"/>

===Main compartment===
The second and main compartment was about {{convert|4|m|ft|abbr=on}} in diameter. Televised views showed enough space for eight large chairs (seven at work consoles), several control panels, and 20 portholes (some obstructed by instruments).<ref name="Nasa 1971-032A"/> The interior design used various colors (light and dark gray, apple green, light yellow) for supporting the cosmonauts’ orientation in weightlessness.<ref>{{Cite book|url=https://books.google.com/books?id=8RWKOxH1c8sC&pg=PA47|title=Architecture for Astronauts: An Activity-based Approach|last=Häuplik-Meusburger|first=Sandra|date=2011|publisher=Springer|isbn=9783709106679|location=Vienna|pages=47|oclc=759926461}}</ref>

===Auxiliary compartments===
The third pressurized compartment contained the control and communications equipment, the power supply, the [[life support system]], and other auxiliary equipment. The fourth and final unpressurized compartment was about 2&nbsp;m in diameter and contained the engine installations and associated control equipment. Salyut had buffer chemical batteries, reserve supplies of oxygen and water, and regeneration systems. Externally mounted were two double sets of [[solar cell]] panels that extended like wings from the smaller compartments at each end, the heat regulation system's [[radiator]]s, and orientation and control devices.<ref name="Nasa 1971-032A"/>

Salyut 1 was modified from one of the [[Almaz]] airframes. The unpressurized service module was the modified service module of a Soyuz craft.{{sfn|Portree|1995}}

===Orion 1 Space Observatory===
The astrophysical [[Orion 1 Space Observatory]] designed by [[Grigor Gurzadyan]] of [[Byurakan Observatory]] in [[Armenia]], was installed in Salyut 1. [[UV astronomy|Ultraviolet spectrograms]] of stars were obtained with the help of a mirror telescope of the [[Marin_Mersenne|Mersenne]] [[Three-mirror_anastigmat|system]] and a [[spectrograph]] of the [[Wadsworth constant deviation system|Wadsworth system]] using film sensitive to the far ultraviolet. The dispersion of the spectrograph was 32&nbsp;[[angstrom|Å]]/mm (3.2&nbsp;nm/mm), while the resolution of the spectrograms derived was about 5&nbsp;Å at 2600&nbsp;Å (0.5&nbsp;nm at 260&nbsp;nm). [[Slitless spectrograms]] were obtained of the stars ''[[Vega]]'' and ''[[Beta Centauri]]'' between 2000 and 3800&nbsp;Å (200 and 380&nbsp;nm).<ref>{{cite journal |title=Observed Energy Distribution of α Lyra and β Cen at 2000–3800 Å |journal=[[Nature (journal)|Nature]] |first1=G. A. |last1=Gurzadyan |first2=J. B. |last2=Ohanesyan |volume=239 |issue=5367 |page=90 |date=September 1972 |doi=10.1038/239090a0 |bibcode=1972Natur.239...90G|s2cid=4265702 |doi-access=free }}</ref> The telescope was operated by crew member [[Viktor Patsayev]], who became the first man to operate a telescope outside of the Earth's atmosphere.<ref name="Marett-Crosby2013">{{cite book|last=Marett-Crosby|first=Michael|title=Twenty-Five Astronomical Observations That Changed the World: And How To Make Them Yourself|url=https://books.google.com/books?id=0KRSphlvsqgC&pg=PA282|access-date=2018-04-18|date=2013-06-28|publisher=Springer Science & Business Media|isbn=9781461468004|page=282|df=mdy-all}}</ref>

==Specifications==
* Length: {{Convert|15.8|m}}
* Maximum diameter: {{Convert|4.15|m}}
* Habitable volume: {{Convert|90|m3}}
* Mass at launch: {{Convert|18900|kg}}
* Launch vehicle: [[Proton-K]] (Serial No.&nbsp;254-01)
* Span across solar arrays: ~{{Convert|10|m}}
* Area of solar arrays: {{Convert|28|m2}}
* Number of solar arrays: 4
* Resupply carriers: Salyut 1-type Soyuz (redesigned Soyuz missions were intended to take place, but this did not occur)
* Number of docking ports: 1
* Total crewed missions: 2
* Total long-duration crewed missions: 1{{sfn|Portree|1995}}

==Visiting spacecraft and crews==
The only spacecraft that ever docked to Salyut 1 were [[Soyuz 10]] and [[Soyuz 11]]. Soyuz 10 failed to hard-dock with Salyut 1 and had to abort the mission. Soyuz 11 conducted experiments in Salyut 1 for 23 days, however the cosmonauts later died during reentry in their Soyuz capsule.

===Soyuz 10===
[[File:Salyut1 with docked Soyuz spacecraft.jpg|thumb|Still frame from an animation of Salyut 1 with attached Soyuz.]]
[[Soyuz 10]] was launched on April 22, 1971, carrying cosmonauts [[Vladimir Shatalov]], [[Aleksei Yeliseyev]], and [[Nikolai Rukavishnikov]]. After taking 24&nbsp;hours for rendezvous and approach, Soyuz 10 soft-docked with Salyut 1 on April 24 at 01:47&nbsp;UTC and remained for 5.5&nbsp;h.<ref name="Nasa 1971-032A"/> Hard-docking was unsuccessful due to technical malfunctions. The crew could not enter the station and had to return to Earth on April 24.{{sfn|Shayler|Hall|2003|p=174}}

===Soyuz 11===
[[File:The Soviet Union 1971 CPA 4060 stamp (Cosmonauts Georgy Dobrovolsky, Vladislav Volkov and Viktor Patsayev).jpg|thumb|The Soyuz 11 crew with the Salyut station in the background, in a Soviet commemorative stamp]]
[[Soyuz 11]] was launched on June 6, 1971 at 04:55:09&nbsp;UTC and took 3 hours and 19 minutes on June 7 to complete docking.<ref>{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-053A |title=Soyuz 11 |work=NSSDC ID: 1971-035A |publisher=NASA |access-date=March 24, 2012}}</ref> The cosmonauts [[Georgy Dobrovolsky]], [[Viktor Patsayev]], and [[Vladislav Volkov]] entered to Salyut 1 and their mission was announced as:<ref name="Nasa 1971-032A"/>
* Checking the design, units, onboard systems, and equipment of the orbital piloted station.
* Testing the station's manual and autonomous procedures for orientation and navigation, as well as the control systems for maneuvering the space complex in orbit.
* Studying Earth's surface geology, geography, meteorology, and snow and ice cover.
* Studying physical characteristics, processes, and phenomena in the atmosphere and outer space in various regions of the electromagnetic spectrum.
* Conducting medico-biological studies to determine the feasibility of having cosmonauts in the station perform various tasks, and studying the influence of space flight on the human organism.

On June 29, after 23 days and flying 362 orbits, the mission was cut short due to problems aboard the station, including an electrical fire. The crew transferred back to Soyuz 11 and reentered the Earth's atmosphere. The capsule parachuted to a soft landing at 23:16:52&nbsp;UTC in [[Kazakhstan]], but the recovery team opened the hatch to find all three crew members dead in their couches. An inquest found that a pressure relief valve had malfunctioned during reentry leading to a loss of cabin atmosphere.{{sfn|Baker|2007|pp=23–25}} The crew were not wearing [[pressure suit]]s, and it was decreed by the TsKBEM (the team of engineers who investigated the tragedy) that all further Soyuz missions would require the use of them.{{sfn|Shayler|Hall|2003|p=180}}

==Reentry of Salyut 1==
<span id="Re-entry"></span>
Salyut 1 was moved to a higher orbit in July–August 1971 to ensure that it would not be destroyed prematurely through [[orbital decay]]. In the meantime, Soyuz capsules were being substantially redesigned to allow pressure suits to be worn during launch, docking maneuvers, and re-entry.{{sfn|Baker|2007|p=25}} The Soyuz redesign effort took too long however, and by September, Salyut 1 was running out of fuel.{{sfn|Shayler|Hall|2003|p=179}} It was decided to conclude the station's mission and on October 11, the main engines were fired for a deorbit maneuver. After 175 days, the world's first space station burned up over the [[Pacific Ocean]].<ref name="Nasa 1971-032A"/>

''[[Pravda]]'' (October 26, 1971) reported that 75% of Salyut 1's studies were carried out by optical means and 20% by radio-technical means, while the remainder involved magnetometrical, gravitational, or other measurements. Synoptic readings were taken in both the visible and invisible parts of the [[electromagnetic spectrum]].<ref name="Nasa 1971-032A">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-032A |title=Salyut 1 |work=NSSDC ID: 1971-032A |publisher=NASA |access-date=March 24, 2012}}</ref>

== See also ==
{{portal|Soviet Union|Spaceflight}}
* {{annotated link|Salyut 6}}
* {{annotated link|Soviet space program}}

==References==
===Citations===
{{Reflist}}

===Sources===
* {{cite book |url=https://books.google.com/books?id=gWkD52bxQYQC |title=The Story of Manned Space Stations: An Introduction |series=Springer-Praxis Books in Astronomy and Space Sciences |publisher=[[Springer Science+Business Media]] |first=Philip |last=Baker |year=2007 |isbn=978-0-387-30775-6}}
* {{cite book |url=https://books.google.com/books?id=EbDGMiXvdG0C |title=Salyut – The First Space Station: Triumph and Tragedy |series=Springer-Praxis Books in Astronomy and Space Sciences |publisher=[[Springer Science+Business Media]] |first=Grujica S. |last=Ivanovich |year=2008 |isbn=978-0-387-73585-6 }}
* {{cite wikisource |title=Mir Hardware Heritage |chapter=Part 2 – Almaz, Salyut, and Mir |first=David S. F. |last=Portree |date=March 1995 |series=Johnson Space Center Reference Series |publisher=NASA |id=NASA Reference Publication 1357 |df=dmy-all }}
* {{cite book |url=https://books.google.com/books?id=dbGchpi1HP8C&pg=PA172 |first1=David J. |last1=Shayler |first2=Rex D. |last2=Hall |title=Soyuz: A Universal Spacecraft |series=Springer-Praxis Books in Astronomy and Space Sciences |publisher=[[Springer Science+Business Media]] |year=2003 |isbn=1-85233-657-9 }}

==External links==
* [http://www.zarya.info/Diaries/StationsDOS/Salyut1.php Salyut 1 chronology] at Zarya.info

{{Salyut Program}}
{{Orbital launches in 1971}}
{{Space stations}}
{{authority control}}

[[Category:Salyut programme]]
[[Category:1971 in the Soviet Union]]
[[Category:Spacecraft launched in 1971]]
[[Category:Spacecraft which reentered in 1971]]
[[Category:Populated places established in 1971]]
[[Category:Soviet inventions]]