A space station is a spacecraft capable of supporting a human crew in outer space for an extended period of time and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station is an artificial satellite (i.e., a type of orbital spaceflight). Stations must have docking ports to allow other spacecraft to dock to transfer crew and supplies. The purpose of maintaining an orbital outpost varies depending on the program. Space stations have most often been launched for scientific purposes, but military launches have also occurred.
Space stations have harboured so far the only long-duration direct human presence in space. After the first station, Salyut 1 (1971), and the deaths of its Soyuz 11 crew, space stations have been operated consecutively since Skylab (1973), having allowed a progression of long-duration direct human presence in space. Stations have been occupied by consecutive crews since 1987 with the Salyut successor Mir. Uninterrupted occupation of stations has been achieved since the operational transition from the Mir to the ISS, with its first occupation in 2000.
The ISS has hosted the highest number of people in orbit at the same time, reaching 13 for the first time during the eleven day docking of STS-127 in 2009. On May 30, 2023 there were 11 people on the ISS and 6 on China's TSS: with a total of 17 people in orbit, it set the record for most people in orbit as of 2023. [1]
As of 2024, there are two fully operational space stations in low Earth orbit (LEO) – the International Space Station (ISS) and China's Tiangong Space Station (TSS). The ISS has been permanently inhabited since October 2000 with the Expedition 1 crews and the TSS began continuous inhabitation with the Shenzhou 14 crews in June 2022. These stations are used to study the effects of spaceflight on the human body, as well as to provide a location to conduct a greater number and longer length of scientific studies than is possible on other space vehicles. In 2022, the TSS finished its phase 1 construction with the addition of two lab modules: Wentian ("Quest for the Heavens"), launched on 24 July 2022, and Mengtian ("Dreaming of the Heavens") launched on 31 October 2022, joining the ISS as the most recent space station operating in orbit. In July 2022, Russia announced intentions to withdraw from the ISS after 2024 in order to build its own space station. [2] There have been numerous decommissioned space stations, including the USSR's Salyuts and Mir, NASA's Skylab, and China's Tiangong 1 and Tiangong 2.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. [3]
‡ = 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 [4] | 3 [5] | 19 April 1971 [6] | 11 October 1971 [7] | 175 | 24 [8] | 6 [9] | 2 [9] | 0 [9] | 18,425 kg (40,620 lb) [6] | 100 m3 (3,500 cu ft) [10] |
MOM [11] | |||||||||||
DOS-2 ‡ | DOS [12] | — [lower-alpha 1] | 29 July 1972 [6] [13] | 29 July 1972 | failed to reach orbit | — | — | — | — | 18,000 kg (40,000 lb) [14] | — |
RVSN [15] | |||||||||||
Salyut 2 ‡ | Almaz [13] | — [lower-alpha 1] | 3 April 1973 [13] | 16 April 1973 [13] | 13 [13] | — | — | — | — | 18,500 kg (40,800 lb) [16] | — |
MOM [17] | |||||||||||
Kosmos 557 ‡ | DOS [18] | — [lower-alpha 1] | 11 May 1973 [19] | 22 May 1973 [20] | 11 | — | — | — | — | 19,400 kg (42,800 lb) [14] | — |
USSR | |||||||||||
Skylab | Skylab [21] | 3 [22] | 14 May 1973 [23] | 11 July 1979 [24] | 2249 | 171 [25] | 9 [26] | 3 [27] | 0 [28] | 77,088 kg (169,950 lb) [29] | 360 m3 (12,700 cu ft) [30] |
NASA | |||||||||||
Salyut 3 | Almaz [4] | 2 [31] | 25 June 1974 [32] | 24 January 1975 [33] | 213 | 15 [34] | 2 [34] | 1 [34] | 0 | 18,900 kg (41,700 lb)* [35] | 90 m3 (3,200 cu ft) [18] |
MOM [17] | |||||||||||
Salyut 4 | DOS [36] | 2 [37] | 26 December 1974 [38] | 3 February 1977 [38] | 770 [38] | 92 [39] | 4 [39] | 2 [39] [40] | 1 [39] | 18,900 kg (41,700 lb) [18] * | 90 m3 (3,200 cu ft) [18] |
MOM [15] | |||||||||||
Salyut 5 | Almaz [36] | 2 [41] | 22 June 1976 [42] | 8 August 1977 [43] | 412 | 67 [44] | 4 [44] | 3 [44] | 0 [44] | 19,000 kg (42,000 lb) [18] * | 100 m3 (3,500 cu ft) [18] |
MOM [17] | |||||||||||
Salyut 6 | DOS [36] [45] | 2 [46] | 29 September 1977 [46] | 29 July 1982 [47] | 1764 | 683 [48] | 33 [48] | 16 [48] | 14 [48] | 19,000 kg (42,000 lb) [49] | 90 m3 (3,200 cu ft) [50] |
MOM [17] | |||||||||||
Salyut 7 | DOS [36] [45] | 3 [51] | 19 April 1982 [52] | 7 February 1991 [52] | 3216 [52] | 861 [51] | 22 [51] | 10 [51] | 15 [51] | 19,000 kg (42,000 lb) [53] | 90 m3 (3,200 cu ft) [18] |
MOM [17] | |||||||||||
Mir | DOS [36] [45] | 3 [54] | 19 February 1986 [55] [lower-alpha 2] | 23 March 2001 [24] [55] | 5511 [55] | 4594 [56] | 125 [56] | 39 [57] | 68 [56] | 129,700 kg (285,900 lb) [58] | 350 m3 (12,400 cu ft) [59] |
| |||||||||||
Tiangong-1 | Tiangong | 3 [60] | 29 September 2011 [61] [62] | 2 April 2018 [63] | 2377 | 22 | 6 [64] [65] | 2 [64] | 1 [66] | 8,506 kg (18,753 lb) [67] | 15 m3 (530 cu ft) [68] |
CMSA | |||||||||||
Tiangong-2 | Tiangong | 2 | 15 September 2016 | 19 July 2019 | 1037 | 29 | 2 | 1 | 1 | 8,506 kg (18,753 lb) [67] | 15 m3 (530 cu ft) [68] |
CMSA |
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 | USAF | MOL | 3 November 1966 [69] | 9 January 1967 [69] | 67 | 9,680 kg (21,340 lb) | 11.3 m3 (400 cu ft) |
Genesis I | Bigelow Aerospace | 12 July 2006 [70] | (In Orbit) | 6512 | 1,360 kg (3,000 lb) [71] | 11.5 m3 (410 cu ft) [72] | |
Genesis II | 28 June 2007 [70] | 6161 | 11.5 m3 (406 cu ft) [72] |
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 [73] | 20 November 1998 [73] [lower-alpha 2] | 9303 | 8592 [74] | 230 [75] | 88 [76] | 94 [76] | 450,000 kg (990,000 lb) [77] | 1,005 m3 (35,500 cu ft) [78] | 388 m3 (13,700 cu ft) | |
Tiangong space station | 3–6 [79] | 29 April 2021 | 1107 | 977 | 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 | Remarks |
---|---|---|---|---|---|
Lunar Gateway | NASA ESA CSA JAXA | Artemis | 4 | 2025 [80] | 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 | Axiom Space | International Space Station programme | TBD | Late 2026 [81] | 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 | Roscosmos | Russia's next generation space station. | TBD | 2027 [82] | 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 | NanoRacks Voyager Space Lockheed Martin Airbus | Private | 4 | 2028 [83] | "Commercial platform supporting a business designed to enable science, research, and manufacturing for customers around the world." |
StarMax | Gravitics | Private | TBD | 2026 [84] | "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 | Blue Origin Sierra Space | Private | 10 | second half 2020s [85] | "Commercial station in LEO for research, industrial, international, and commercial customers." |
Bharatiya Antariksha Station [86] | ISRO | Indian Human Spaceflight Programme | 3 | ~2035 [87] [88] [89] [90] [91] | ISRO chairman K. Sivan announced in 2019 that India will not join the International Space Station, but will instead build a 20 ton space station of its own. [92] It is intended to be built 5–7 years after the conclusion of the Gaganyaan program. [93] |
Lunar Orbital Station [94] | Roscosmos | TBD | after 2030 [95] | ||
Haven-1 | Vast | 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 | Sierra Space | 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] |
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 | USAF | 2 [99] | 1969 | Boilerplate mission launched successfully, wider project cancelled due to excessive costs [100] |
Skylab B | NASA | 3 [101] | 1976 | Constructed, but launch cancelled due to lack of funding. [102] Now a museum piece. |
OPS-4 | USSR | 3 [103] | 1979 | Constructed, but Almaz program cancelled in favour of uncrewed recon satellites. |
Freedom | NASA | 14–16 [104] | 1993 | Merged to form the basis of the International Space Station. |
Mir-2 | USSR Roscosmos | 2 [105] | ||
Columbus MTFF | ESA | 3 | ||
Galaxy | Bigelow Aerospace | Robotic [106] | 2007 | Canceled due to rising costs and ability to ground test key Galaxy subsystems [107] |
Sundancer | 3 | 2011 | Was under construction, but cancelled in favour of developing B330. | |
Almaz commercial | Excalibur Almaz | 4+ | 2016 | Soviet hardware was acquired, but never launched due to lack of funds. |
Tiangong-3 | CNSA | 3 | 2017 | The goals for Tiangong-2 and 3 were merged, and were completed by a single station rather than two separate stations. |
OPSEK | Roscosmos | 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 | Bigelow Aerospace | 3 | 2020 | Test articles were constructed but not flight ready hardware; cancelled due to the COVID-19 pandemic. |
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.
Human spaceflight is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be remotely operated from ground stations on Earth, or autonomously, without any direct human involvement. People trained for spaceflight are called astronauts, cosmonauts (Russian), or taikonauts (Chinese); and non-professionals are referred to as spaceflight participants or spacefarers.
A space station is a spacecraft capable of supporting a human crew in outer space for an extended period of time and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station is an artificial satellite. Stations must have docking ports to allow other spacecraft to dock to transfer crew and supplies. The purpose of maintaining an orbital outpost varies depending on the program. Space stations have most often been launched for scientific purposes, but military launches have also occurred.
Mir was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by Russia. 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.
The Tiangong program is China's space program to create a modular space station, comparable to Mir. This program is independent and unconnected to any other international space-active countries. The program is part of the China Manned Space Program that began in 1992. The core module of the Tiangong space station, the Tianhe was finally launched on 29 April 2021 marking the start of the Tiangong Space program deployment.
The Orlan space suit is a series of semi-rigid one-piece space suit models designed and built by NPP Zvezda. They have been used for spacewalks (EVAs) in the Russian space program, the successor to the Soviet space program, and by space programs of other countries, including NASA.
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 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.
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.