The image above contains clickable links Size comparisons between current and past space stations as they appeared most recently. Solar panels in blue, heat radiators in red. Stations have different depths not shown by silhouettes.
Space stations have been hosting the only continuouspresence of humans in space. The first space station wasSalyut 1 (1971), hosting the first crew, of the ill-fatedSoyuz 11. Consecutively space stations have been operated sinceSkylab (1973) and occupied since 1987 with theSalyut successorMir. Uninterrupted occupation has been sustained since the operational transition from the Mir to theInternational Space Station (ISS), with its first occupation in 2000.
Currently there are two fully operational space stations – the ISS andChina'sTiangong Space Station (TSS), which have been occupied since October 2000 withExpedition 1 and since June 2022 withShenzhou 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 ofthe 127thSpace 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 oftenmodular, featuringdocking 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 featurethrusters forstation keeping.
First description of arotating space station, inHermann Noordung'sThe Problem of Space Travel (1929). (Legend:Achs-Körper:axle body.Aufzugschacht:elevator shaft.K: electric cable to an external observatory.Kondensatorrohre: condenser pipes.S:airlock.Treppenschacht:stairwell.Verdampfungsrohr: boiler pipe).
The first human flew to space and concluded the first orbit on April 12, 1961, withVostok 1.
TheApollo program had inits early planning instead of alunar landing a crewedlunar orbital flight and an orbital laboratory station in orbit of Earth, at times calledProject Olympus, as two different possible program goals, until theKennedy administration sped ahead and made the Apollo program focus on what was originally planned to come after it, the lunar landing. The Project Olympus space station, or orbiting laboratory of the Apollo program, was proposed as an in-space unfolded structure with theApollo command and service module docking.[5] While never realized, the Apollo command and service module would performdocking maneuvers and eventually become a lunar orbiting module which was used for station-like purposes.
In January 1969,Soyuz 4 andSoyuz 5 performed the first docked, but not internal, crew transfer, and in March,Apollo 9 performed the first ever internal transfer of astronauts between two docked spaceships.
Skylab (1973–1974), the first U.S. space station and second overall
In 1971, theSoviet Union developed and launched the world's first space station,Salyut 1.[6] TheAlmaz andSalyut series were eventually joined bySkylab,Mir, andTiangong-1 andTiangong-2. The hardware developed during the initial Soviet efforts remains in use, with evolved variants comprising a considerable part of the ISS, orbiting today. Each crew member stays aboard the station for weeks or months but rarely more than a year.
Early stations were monolithic designs that were constructed and launched in one piece, generally containing all their supplies and experimental equipment. A crew would then be launched to join the station and perform research. After the supplies had been consumed, the station was abandoned.[6]
The first space station wasSalyut 1, which was launched by theSoviet Union on April 19, 1971. The early Soviet stations were all designated "Salyut", but among these, there were two distinct types: civilian and military. The military stations,Salyut 2,Salyut 3, andSalyut 5, were also known asAlmaz stations.[7]
The civilian stationsSalyut 6 andSalyut 7 were built with two docking ports, which allowed a second crew to visit, bringing a new spacecraft with them; theSoyuz ferry could spend 90 days in space, at which point it needed to be replaced by a fresh Soyuz spacecraft.[8] This allowed for a crew to man the station continually. The AmericanSkylab (1973–1979) was also equipped with two docking ports, like second-generation stations, but the extra port was never used. The presence of a second port on the new stations allowedProgress supply vehicles to be docked to the station, meaning that fresh supplies could be brought to aid long-duration missions. This concept was expanded on Salyut 7, which "hard docked" with aTKS tug shortly before it was abandoned; this served as a proof of concept for the use of modular space stations. The later Salyuts may reasonably be seen as a transition between the two groups.[7]
Unlike previous stations, the Soviet space stationMir had amodular design; a core unit was launched, and additional modules, generally with a specific role, were later added. This method allows for greater flexibility in operation, as well as removing the need for a single immensely powerfullaunch vehicle. Modular stations are also designed from the outset to have their supplies provided by logistical support craft, which allows for a longer lifetime at the cost of requiring regular support launches.[9]
The Russian Orbital Segment's "second-generation" modules were able to launch onProton, fly to the correct orbit, and dock themselves without human intervention.[11] Connections are automatically made for power, data, gases, and propellants. The Russian autonomous approach allows the assembly of space stations prior to the launch of crew.
The Russian "second-generation" modules are able to be reconfigured to suit changing needs. As of 2009,RKK Energia was considering the removal and reuse of some modules of the ROS on theOrbital Piloted Assembly and Experiment Complex after the end of mission is reached for the ISS.[12] However, in September 2017, the head of Roscosmos said that the technical feasibility of separating the station to form OPSEK had been studied, and there were now no plans to separate the Russian segment from the ISS.[13]
In contrast, the main US modules launched on theSpace Shuttle and were attached to the ISS by crews duringEVAs. Connections for electrical power, data, propulsion, and cooling fluids are also made at this time, resulting in an integrated block of modules that is not designed for disassembly and must be deorbited as one mass.[14]
Axiom Station is a planned commercial space station that will begin as a single module docked to the ISS.Axiom Space gained NASA approval for the venture in January 2020. The first module, the Payload Power Transfer Module (PPTM), is expected to be launched to the ISS no earlier than 2027.[15] PPTM will remain at the ISS until the launch of Axiom's Habitat One (Hab-1) module about one year later, after which it will detach from the ISS to join with Hab-1.[15]
Rendering of the completed Tiangong Space Station in November 2022
China's first space laboratory,Tiangong-1 was launched in September 2011.[16] The uncrewedShenzhou 8 then successfully performed an automatic rendezvous and docking in November 2011. The crewedShenzhou 9 then docked with Tiangong-1 in June 2012, followed by the crewedShenzhou 10 in 2013.[citation needed]
A second space laboratoryTiangong-2 was launched in September 2016, while a plan forTiangong-3 was merged with Tiangong-2.[19] The station made a controlled reentry on 19 July 2019 and burned up over the South Pacific Ocean.[20]
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.
"Scheduled to be the world's first commercial space station, Haven-1 and subsequent human spaceflight missions will accelerate access to space exploration"[27]
"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".[29]
"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."
With Russia leaving the ISS programme sometime after 2024, Roscosmos announced this new space station in April 2021 as the replacement for that program.
ISRO chairmanK. Sivan announced in 2019 that India will not join theInternational Space Station, but will instead build a space station of its own.[40] of 52 Tonne Mass[41] It is intended to be completed 5–7 years after the conclusion of theGaganyaan program.[42]
"Commercial platform supporting a business designed to enable science, research, and manufacturing for customers around the world."
While originallyLockheed Martin was included in the project, as of 2024, it appears their primary role has been filled byAirbus, to provide the main habitat for the station.[44] As of 2024, they are no longer listed as a partner on Starlab's website.[45]
A planned successor to Haven-1. Vast CEO Max Hoat expressed hope that the first module of Haven-2 will be launched in 2028 if the station will be approved during the second phase of NASA'sCommercial LEO Destinations program.[46]
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.[49][50][51]
Two types of space stations have been flown: monolithic and modular. Monolithic stations consist of a single vehicle and are launched by one rocket. Modular stations consist of two or more separate vehicles that are launched independently and docked on orbit. Modular stations are currently preferred due to lower costs and greater flexibility.[52][53]
A space station is a complex vehicle that must incorporate many interrelated subsystems, including structure, electrical power, thermal control,attitude determination and control, orbital navigation and propulsion, automation and robotics, computing and communications, environmental and life support, crew facilities, and crew and cargo transportation. Stations must serve a useful role, which drives the capabilities required.[citation needed]
Space stations are made from durable materials that have to weatherspace radiation, internal pressure,micrometeoroids, thermal effects of the sun and cold temperatures for long periods of time. They are typically made fromstainless steel,titanium and high-qualityaluminum alloys, with layers of insulation such asKevlar as a ballistics shield protection.[54]
The International Space Station (ISS) has a single inflatable module, theBigelow Expandable Activity Module, which was installed in April2016 after being delivered to the ISS on theSpaceX CRS-8 resupply mission.[55][56] This module, based on NASA research in the 1990s, weighs 1,400 kilograms (3,100 lb) and was transported while compressed before being attached to the ISS by the space station arm and inflated to provide a 16 cubic metres (21 cu yd) volume. Whilst it was initially designed for a 2year lifetime it was still attached and being used for storage in August 2022.[57][58]
The space station environment presents a variety of challenges to human habitability, including short-term problems such as the limited supplies of air, water, and food and the need to managewaste heat, and long-term ones such asweightlessness and relatively high levels ofionizing radiation. These conditions can create long-term health problems for space-station inhabitants, includingmuscle atrophy,bone deterioration,balance disorders,eyesight disorders, and elevated risk ofcancer.[59]
Futurespace habitats may attempt to address these issues, and could be designed for occupation beyond the weeks or months that current missions typically last. Possible solutions include the creation ofartificial gravity by arotating structure, the inclusion ofradiation shielding, and the development of on-site agricultural ecosystems. Some designs might even accommodate large numbers of people, becoming essentially "cities in space" where people would reside semi-permanently.[60]
Molds that develop aboard space stations can produce acids that degrade metal, glass, and rubber. Despite an expanding array of molecular approaches for detecting microorganisms, rapid and robust means of assessing the differential viability of the microbial cells, as a function of phylogenetic lineage, remain elusive.[61]
Space station air and water is brought up in spacecraft from Earth before being recycled. Supplementaloxygen can be supplied by asolid fuel oxygen generator.[63]
Space stations have harboured so far the only long-duration direct human presence in space. After the first station,Salyut 1 (1971), and its tragicSoyuz 11 crew, space stations have been operated consecutively sinceSkylab (1973–1974), having allowed a progression of long-duration direct human presence in space. Long-duration resident crews have been joined by visiting crews since 1977 (Salyut 6), and stations have been occupied by consecutive crews since 1987 with theSalyut successorMir. Uninterrupted occupation of stations has been achieved since the operational transition from the Mir to theISS, 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 ofSTS-127 in 2009.[67]
Many spacecraft are used to dock with the space stations. Soyuz flightT-15 in March to July 1986 was the first and as of 2016, only spacecraft to visit two different space stations,Mir andSalyut 7.[69]
Research conducted on the Mir included the first long term space based ESA research project EUROMIR95 which lasted 179days and included 35 scientific experiments.[108]
During the first 20 years of operation of the International Space Station, there were around 3,000 scientific experiments in the areas of biology and biotech, technology development, educational activities, human research, physical science, and Earth and space science.[109][110]
Space stations provide a useful platform to test the performance, stability, and survivability of materials in space. This research follows on from previous experiments such as theLong Duration Exposure Facility, a free flying experimental platform which flew from April1984 until January1990.[111][112]
As it currently costs on average $10,000 to $25,000 per kilogram to launch anything into orbit, space stations remain the exclusive province of government space agencies, which are primarily funded bytaxation. In the case of theInternational Space Station,space tourism makes up a small portion of money to run it.
"The Brick Moon" – an 1869 serial byEdward Everett Hale – was the first fictional space station or habitat.The concepts of space stations andspace habitats feature inscience fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations (thoughgeneration ships also fit this description, they are usually not considered space habitats as they are heading for a destination[117]), but the line between the two is fuzzy with significant overlap and the term space station is sometimes used for both concepts.[118][119] The first such artificial satellite in fiction wasEdward Everett Hale's "The Brick Moon" in 1869,[118][120] a sphere of bricks 61 meters across accidentally launched into orbit around the Earth with people still onboard.[117][121]
^de Groh, Kim K.; Banks, Bruce A.; Dever, Joyce A.; Jaworske, Donald A.; Miller, Sharon K. R.; Sechkar, Edward A.; Panko, Scott R. (March 2008).International Space Station Experiments (Misse 1–7)(PDF). International Symposium on SM/MPAC and SEED Experiments. Tsukuba, Japan:NASA (published August 2009).hdl:2060/20090005995.S2CID54880762. TM-2008-215482.Archived(PDF) from the original on 12 June 2024.
Neri Vela, Rodolfo (1990).Manned space stations" Their construction, operation and potential application. Paris: European Space Agency SP-1137.ISBN978-92-9092-124-0.
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