A space station (or orbital station) is a spacecraft which remains in orbit and hosts humans for extended periods of time. It therefore is an artificial satellite featuring habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served military or commercial uses, such as hosting space tourists.
Space stations have been hosting the only continuous presence of humans in space. The first space station was Salyut 1 (1971), hosting the first crew, of the ill-fated Soyuz 11. Consecutively space stations have been operated since Skylab (1973) and occupied since 1987 with the Salyut successor Mir. Uninterrupted occupation has been sustained since the operational transition from the Mir to the International Space Station (ISS), with its first occupation in 2000.
Currently there are two fully operational space stations – the International Space Station (ISS) and China's Tiangong Space Station (TSS), which have been occupied since October 2000 with Expedition 1 and since June 2022 with Shenzhou 14. The highest number of people at the same time on one space station has been 13, first achieved with the eleven day docking to the ISS of the 127th Space Shuttle mission in 2009. The record for most people on all space stations at the same time has been 17, first on May 30, 2023, with 11 people on the ISS and 6 on the TSS. [1]
Space stations are most often modular, featuring docking ports, through which they are built and maintained, allowing the joining or movement of modules and the docking of other spacecrafts for the exchange of people, supplies and tools. While space stations generally do not leave their orbit, they do feature thrusters for station keeping.These stations have re-entered the atmosphere and disintegrated.
The Soviet Union ran two programs simultaneously in the 1970s, both of which were called Salyut publicly. The Long Duration Orbital Station (DOS) program was intended for scientific research into spaceflight. The Almaz program was a secret military program that tested space reconnaissance. [2]
‡ = Never crewed
Name | Program Entity | Crew size | Launched | Reentered | Days in orbit | Days occu- pied | Total crew and visitors | Number of crewed visits | Number of robotic visits | Mass (* = at launch) | Pressurized volume |
---|---|---|---|---|---|---|---|---|---|---|---|
Salyut 1 | DOS [3] | 3 [4] | 19 April 1971 [5] | 11 October 1971 [6] | 175 | 24 [7] | 6 [8] | 2 [8] | 0 [8] | 18,425 kg (40,620 lb) [5] | 100 m3 (3,500 cu ft) [9] |
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DOS-2 ‡ | DOS [10] | — [lower-alpha 1] | 29 July 1972 [5] [11] | 29 July 1972 | failed to reach orbit | — | — | — | — | 18,000 kg (40,000 lb) [12] | — |
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Salyut 2 ‡ | Almaz [11] | — [lower-alpha 1] | 3 April 1973 [11] | 16 April 1973 [11] | 13 [11] | — | — | — | — | 18,500 kg (40,800 lb) [14] | — |
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Kosmos 557 ‡ | DOS [16] | — [lower-alpha 1] | 11 May 1973 [17] | 22 May 1973 [18] | 11 | — | — | — | — | 19,400 kg (42,800 lb) [12] | — |
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Skylab | Skylab [19] | 3 [20] | 14 May 1973 [21] | 11 July 1979 [22] | 2249 | 171 [23] | 9 [24] | 3 [25] | 0 [26] | 77,088 kg (169,950 lb) [27] | 360 m3 (12,700 cu ft) [28] |
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Salyut 3 | Almaz [3] | 2 [29] | 25 June 1974 [30] | 24 January 1975 [31] | 213 | 15 [32] | 2 [32] | 1 [32] | 0 | 18,900 kg (41,700 lb)* [33] | 90 m3 (3,200 cu ft) [16] |
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Salyut 4 | DOS [34] | 2 [35] | 26 December 1974 [36] | 3 February 1977 [36] | 770 [36] | 92 [37] | 4 [37] | 2 [37] [38] | 1 [37] | 18,900 kg (41,700 lb) [16] * | 90 m3 (3,200 cu ft) [16] |
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Salyut 5 | Almaz [34] | 2 [39] | 22 June 1976 [40] | 8 August 1977 [41] | 412 | 67 [42] | 4 [42] | 3 [42] | 0 [42] | 19,000 kg (42,000 lb) [16] * | 100 m3 (3,500 cu ft) [16] |
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Salyut 6 | DOS [34] [43] | 2 [44] | 29 September 1977 [44] | 29 July 1982 [45] | 1764 | 683 [46] | 33 [46] | 16 [46] | 14 [46] | 19,000 kg (42,000 lb) [47] | 90 m3 (3,200 cu ft) [48] |
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Salyut 7 | DOS [34] [43] | 3 [49] | 19 April 1982 [50] | 7 February 1991 [50] | 3216 [50] | 861 [49] | 22 [49] | 10 [49] | 15 [49] | 19,000 kg (42,000 lb) [51] | 90 m3 (3,200 cu ft) [16] |
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Mir | DOS [34] [43] | 3 [52] | 19 February 1986 [53] [lower-alpha 2] | 23 March 2001 [22] [53] | 5511 [53] | 4594 [54] | 125 [54] | 39 [55] | 68 [54] | 129,700 kg (285,900 lb) [56] | 350 m3 (12,400 cu ft) [57] |
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Tiangong-1 | Tiangong | 3 [58] | 29 September 2011 [59] [60] | 2 April 2018 [61] | 2377 | 22 | 6 [62] [63] | 2 [62] | 1 [64] | 8,506 kg (18,753 lb) [65] | 15 m3 (530 cu ft) [66] |
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Tiangong-2 | Tiangong | 2 | 15 September 2016 | 19 July 2019 | 1037 | 29 | 2 | 1 | 1 | 8,506 kg (18,753 lb) [65] | 15 m3 (530 cu ft) [66] |
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These stations are prototypes; they only exist as testing platforms and were never intended to be crewed. OPS 0855 was part of a cancelled Manned Orbiting Laboratory project by the United States, while the Genesis stations were launched privately. The Genesis stations were "retired" when their avionics systems stopped working after two and a half years, yet they still remain in orbit as derelict spacecraft.
Name | Entity | Program | Launched | Reentered | Days in orbit | Mass | Pressurized volume |
---|---|---|---|---|---|---|---|
OPS 0855 | ![]() | MOL | 3 November 1966 [67] | 9 January 1967 [67] | 67 | 9,680 kg (21,340 lb) | 11.3 m3 (400 cu ft) |
Genesis I | ![]() | 12 July 2006 [68] | (In Orbit) | 6617 | 1,360 kg (3,000 lb) [69] | 11.5 m3 (410 cu ft) [70] | |
Genesis II | 28 June 2007 [68] | 6266 | 11.5 m3 (406 cu ft) [70] |
As of 2024, two stations are orbiting Earth with life support system in place and fully operational.
Name | Entity | Crew size | Launched | Days in orbit [lower-alpha 3] | Days occupied | Total crew and visitors | Crewed visits | Robotic visits | Mass | Pressurized volume | Habitable volume |
---|---|---|---|---|---|---|---|---|---|---|---|
International Space Station | 7 [71] | 20 November 1998 [71] [lower-alpha 2] | 9408 | 8697 [72] | 230 [73] | 88 [74] | 94 [74] | 450,000 kg (990,000 lb) [75] | 1,005 m3 (35,500 cu ft) [76] | 388 m3 (13,700 cu ft) | |
Tiangong space station | 3–6 [77] | 29 April 2021 | 1212 | 1082 | 19 | 7 | 8 | 100,000 kg (220,000 lb) | 340 m3 (12,000 cu ft) | 122 m3 (4,310 cu ft) |
These space stations have been announced by their host entity and are currently in planning, development or production. The launch date listed here may change as more information becomes available.
Name | Entity | Program | Crew size | Launch date | Planned Pressurized Volume | Remarks |
---|---|---|---|---|---|---|
Lunar Gateway | ![]() ![]() ![]() ![]() | Artemis | 4 | 2025 [78] | ≥125 m3 (4,400 cu ft) | Intended to serve as a science platform and as a staging area for the lunar landings of NASA's Artemis program and follow-on human mission to Mars. |
Axiom Station | ![]() | International Space Station programme | TBD | Late 2026 [79] | ~666.8 m3 (~23,548 cu ft) | Eventually will detach from the ISS in the early 2030s and form a private, free flying space station for commercial tourism and science activities. |
Russian Orbital Service Station | ![]() | Russia's next generation space station. | TBD | 2027 [80] | With Russia leaving the ISS programme sometime after 2024, Roscosmos announced this new space station in April 2021 as the replacement for that program. | |
Starlab | ![]() ![]() ![]() ![]() ![]() | Private | 4 | 2028 [81] | ~450 m3 (~15892 cu ft) | "Commercial platform supporting a business designed to enable science, research, and manufacturing for customers around the world." While originally Lockheed Martin was included in the project, as of 2024, it appears their primary role has been filled by Airbus, to provide the main habitat for the station. [82] As of 2024, they are no longer listed as a partner on Starlab's website. [83] |
StarMax | ![]() | Private | TBD | 2026 [84] | 400 m3 (14,126 cu ft) | "The StarMax module provides up to 400 cubic meters of usable habitable volume - nearly half the volume of the International Space Station in one module." |
Orbital Reef | ![]() ![]() | Private | 10 | second half 2020s [85] | 830 m3 (29,000 cu ft) | "Commercial station in LEO for research, industrial, international, and commercial customers." |
Bharatiya Antariksha Station [86] | ![]() | Indian Human Spaceflight Programme | 3 | ~2035 [86] [87] [88] [89] [90] | ISRO chairman K. Sivan announced in 2019 that India will not join the International Space Station, but will instead build a space station of its own. [91] of 52 Tonne Mass [92] It is intended to be built 5–7 years after the conclusion of the Gaganyaan program. [93] | |
Lunar Orbital Station [94] | ![]() | TBD | after 2030 [95] | |||
Haven-1 | ![]() | Private | 4 | 2025 [96] | "Scheduled to be the world's first commercial space station, Haven-1 and subsequent human spaceflight missions will accelerate access to space exploration" [97] | |
LIFE Pathfinder | ![]() | Private | TBD | 2026 | "Before offering LIFE for Orbital Reef, though, the company is proposing to launch a standalone “pathfinder” version of LIFE as soon as the end of 2026". [98] | |
Japanese Space Station Module (Mitsui) | ![]() | TBA | TBD | TBD | Japan's spaceflight agency, JAXA, announced in July 2024 that has contracted Mitsui & Co. to develop a concept for a new space station module for eventual flight and docking to an American private space station as yet to be determined as of the initial announcement. [99] [100] [101] |
Most of these stations were canceled due to financial difficulties, or merged into other projects.
Name | Entity | Crew | Cancellation | Remarks |
---|---|---|---|---|
Manned Orbiting Laboratory 1–7 | ![]() | 2 [102] | 1969 | Boilerplate mission launched successfully, wider project cancelled due to excessive costs [103] |
Skylab B | ![]() | 3 [104] | 1976 | Constructed, but launch cancelled due to lack of funding. [105] Now a museum piece. |
OPS-4 | ![]() | 3 [106] | 1979 | Constructed, but Almaz program cancelled in favour of uncrewed recon satellites. |
Freedom | ![]() | 14–16 [107] | 1993 | Merged to form the basis of the International Space Station. |
Mir-2 | ![]() ![]() | 2 [108] | ||
Columbus MTFF | ![]() | 3 | ||
Galaxy | ![]() | Robotic [109] | 2007 | Canceled due to rising costs and ability to ground test key Galaxy subsystems [110] |
Sundancer | 3 | 2011 | Was under construction, but cancelled in favour of developing B330. | |
Almaz commercial | ![]() | 4+ | 2016 | Soviet hardware was acquired, but never launched due to lack of funds. |
Tiangong-3 | ![]() | 3 | 2017 | The goals for Tiangong-2 and 3 were merged, and were completed by a single station rather than two separate stations. |
OPSEK | ![]() | 2+ | 2017 | Some modules such as Nauka were launched and attached to the ISS- but proposals to split these off as a separate station were cancelled, and they instead remain part of the ISS. |
B330 | ![]() | 3 | 2020 | Test articles were constructed but not flight ready hardware; cancelled due to the COVID-19 pandemic. |
Northrop Grumman CLD | Northrop Grumman | 4-8 [111] | 2023 | Developed under the Commercial LEO Destinations program, cancelled by Northrop Grumman to partner with Nanoracks on Starlab. |
Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA includes spacewalks and lunar or planetary surface exploration. In a stand-up EVA (SEVA), an astronaut stands through an open hatch but does not fully leave the spacecraft. EVAs have been conducted by the Soviet Union/Russia, the United States, Canada, the European Space Agency and China.
The International Space Station (ISS) is a large space station assembled and maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA, Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). The ISS is the largest space station ever built. Its primary purpose is to perform microgravity and space environment experiments.
A space station is a spacecraft which remains in orbit and hosts humans for extended periods of time. It therefore is an artificial satellite featuring habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served military or commercial uses, such as hosting space tourists.
Mir was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by the Russian Federation. Mir was the first modular space station and was assembled in orbit from 1986 to 1996. It had a greater mass than any previous spacecraft. At the time it was the largest artificial satellite in orbit, succeeded by the International Space Station (ISS) after Mir's orbit decayed. The station served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology, and spacecraft systems with a goal of developing technologies required for permanent occupation of space.
The Salyut programme was the first space station programme, undertaken by the Soviet Union. It involved a series of four crewed scientific research space stations and two crewed military reconnaissance space stations over a period of 15 years, from 1971 to 1986. Two other Salyut launches failed. In one respect, Salyut had the task of carrying out long-term research into the problems of living in space and a variety of astronomical, biological and Earth-resources experiments, and on the other hand the USSR used this civilian programme as a cover for the highly secretive military Almaz stations, which flew under the Salyut designation. Salyut 1, the first station in the programme, became the world's first crewed space station.
Human spaceflight programs have been conducted, started, or planned by multiple countries and companies. Until the 21st century, human spaceflight programs were sponsored exclusively by governments, through either the military or civilian space agencies. With the launch of the privately funded SpaceShipOne in 2004, a new category of human spaceflight programs – commercial human spaceflight – arrived. By the end of 2022, three countries and one private company (SpaceX) had successfully launched humans to Earth orbit, and two private companies had launched humans on a suborbital trajectory.
The Almaz program was a highly secret Soviet military space station program, begun in the early 1960s.
The TKS spacecraft was a Soviet spacecraft conceived in the late 1960s for resupply flights to the military Almaz space station.
The Shuttle–Mir program was a collaborative 11-mission space program between Russia and the United States that involved American Space Shuttles visiting the Russian space station Mir, Russian cosmonauts flying on the Shuttle, and an American astronaut flying aboard a Soyuz spacecraft to engage in long-duration expeditions aboard Mir.
A space rendezvous is a set of orbital maneuvers during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance. Rendezvous requires a precise match of the orbital velocities and position vectors of the two spacecraft, allowing them to remain at a constant distance through orbital station-keeping. Rendezvous may or may not be followed by docking or berthing, procedures which bring the spacecraft into physical contact and create a link between them.
Mir, DOS-7, was the first module of the Soviet/Russian Mir space station complex, in low Earth orbit from 1986 to 2001. Generally referred to as either the core module or base block, the module was launched on 20 February 1986 on a Proton-K rocket from LC-200/39 at the Baikonur Cosmodrome. The spacecraft was generally similar in design to the two previous Soviet orbital stations, Salyut 6 and Salyut 7, however possessed a revolutionary addition in the form of a multiple docking node at the forward end of the module. This, in addition to the docking port at the rear of the spacecraft, allowed five additional modules to be docked directly to DOS-7, greatly expanding the station's capabilities.
The International Space Station programme is tied together by a complex set of legal, political and financial agreements between the fifteen nations involved in the project, governing ownership of the various components, rights to crewing and utilisation, and responsibilities for crew rotation and resupply of the International Space Station. It was conceived in September 1993 by the United States and Russia after 1980s plans for separate American (Freedom) and Soviet (Mir-2) space stations failed due to budgetary reasons. These agreements tie together the five space agencies and their respective International Space Station programmes and govern how they interact with each other on a daily basis to maintain station operations, from traffic control of spacecraft to and from the station, to utilisation of space and crew time. In March 2010, the International Space Station Program Managers from each of the five partner agencies were presented with Aviation Week's Laureate Award in the Space category, and the ISS programme was awarded the 2009 Collier Trophy.
The Russian Orbital Segment (ROS) is the name given to the components of the International Space Station (ISS) constructed in Russia and operated by the Russian Roscosmos. The ROS handles Guidance, Navigation, and Control for the entire Station.
The Orbital Piloted Assembly and Experiment Complex was a 2009–2017 proposed third-generation Russian modular space station for low Earth orbit. The concept was to use OPSEK to assemble components of crewed interplanetary spacecraft destined for the Moon, Mars, and possibly Saturn. The returning crew could also recover on the station before landing on Earth. Thus, OPSEK could form part of a future network of stations supporting crewed exploration of the Solar System.
Docking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules.
Tianhe, officially the Tianhe core module, is the first module to launch of the Tiangong space station. It was launched into orbit on 29 April 2021, as the first launch of the final phase of Tiangong program, part of the China Manned Space Program.
The S5.80 is a liquid pressure-fed rocket engine burning N2O4/UDMH with an O/F of 1.85. It is used for crew-rated spacecraft propulsion applications. It is currently used in the Soyuz-TMA-M spacecraft propulsion module KTDU-80, and its sibling, the S5.79 rocket engine, is still used as the main propulsion of the Zvezda ISS module. The S5.80 generates 2.95 kN (660 lbf) of thrust with a chamber pressure of 0.88 MPa (128 psi) and a nozzle expansion of 153.8 that enables it to achieve a specific impulse of 302 s (2.96 km/s). It is rated for 30 starts with a total firing time of 890 seconds. The engine, without the pressurization system or propellant tanks, weighs 310 kg (680 lb) and is an integrated unit that is 1.2 m (47 in) long with a diameter of 2.1 m (83 in).
Ondler said in the briefing that the first of those modules is now scheduled to launch to the ISS at the end of 2026, about a year later than the company previously announced.