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65-401: The process of collecting sunlight, converting it to electricity, and managing and distributing this electricity builds up excess heat that can damage spacecraft equipment. This heat must be eliminated for reliable operation of the space station in orbit. The ISS power system uses radiators to dissipate the heat away from the spacecraft. The radiators are shaded from sunlight and aligned toward

130-576: A concept for a rotating wheel space station in Collier's Weekly , referencing Potočnik's idea. However, development of a rotating station was never begun in the 20th century. The first human flew to space and concluded the first orbit on April 12, 1961, with Vostok 1 . The Apollo program had in its early planning instead of a lunar landing a crewed lunar orbital flight and an orbital laboratory station in orbit of Earth, at times called Project Olympus , as two different possible program goals, until

195-475: A consequence the cells can withstand overcharging as long as the heat generated can be dissipated. The cells have the disadvantage of relatively high self-discharge rate, i.e. chemical reduction of Ni(III) into Ni(II) in the cathode: which is proportional to the pressure of hydrogen in the cell; in some designs, 50% of the capacity can be lost after only a few days' storage. Self-discharge is less at lower temperature. Compared with other rechargeable batteries,

260-702: A longer lifetime at the cost of requiring regular support launches. The ISS is divided into two main sections, the Russian Orbital Segment (ROS) and the US Orbital Segment (USOS). The first module of the ISS, Zarya , was launched in 1998. The Russian Orbital Segment's "second-generation" modules were able to launch on Proton , fly to the correct orbit, and dock themselves without human intervention. Connections are automatically made for power, data, gases, and propellants. The Russian autonomous approach allows

325-500: A lunar orbiting module which was used for station-like purposes. But before that the Gemini program paved the way and achieved the first space rendezvous (undocked) with Gemini 6 and Gemini 7 in 1965. Subsequently in 1966 Neil Armstrong performed on Gemini 8 the first ever space docking, while in 1967 Kosmos 186 and Kosmos 188 were the first spacecrafts that docked automatically. In January 1969, Soyuz 4 and Soyuz 5 performed

390-410: A nickel–hydrogen battery provides good specific energy of 55–60 watt-hours/kg, and very long cycle life (40,000 cycles at 40% DOD) and operating life (> 15 years) in satellite applications. The cells can tolerate overcharging and accidental polarity reversal, and the hydrogen pressure in the cell provides a good indication of the state of charge. However, the gaseous nature of hydrogen means that

455-561: A pressurized cell at up to 1200  psi (82.7  bar ) pressure. The nickel–hydrogen battery was patented in the United States on February 25, 1971 by Alexandr Ilich Kloss , Vyacheslav Mikhailovic Sergeev and Boris Ioselevich Tsenter from the Soviet Union. NiH 2 cells using 26% potassium hydroxide (KOH) as an electrolyte have shown a service life of 15 years or more at 80% depth of discharge (DOD) The energy density

520-420: A primary bus voltage set to V mp , the peak power point of the solar arrays. As of 30 December 2005, V mp was 160 volts DC ( direct current ). It can change over time as the arrays degrade from ionizing radiation. Microprocessor-controlled switches control the distribution of primary power throughout the station. The battery charge/discharge units (BCDUs) regulate the amount of charge put into

585-458: A second crew to visit, bringing a new spacecraft with them; the Soyuz ferry could spend 90 days in space, at which point it needed to be replaced by a fresh Soyuz spacecraft. This allowed for a crew to man the station continually. The American Skylab (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

650-423: A sequential shunt unit (SSU) that provides coarse voltage regulation at the desired V mp . The SSU applies a "dummy" (resistive) load that increases as the station's load decreases (and vice versa) so the array operates at a constant voltage and load. The SSUs are provided by SS/L. DC-to-DC converter units supply the secondary power system at a constant 124.5 volts DC, allowing the primary bus voltage to track

715-579: 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 manage waste heat , and long-term ones such as weightlessness and relatively high levels of ionizing radiation . These conditions can create long-term health problems for space-station inhabitants, including muscle atrophy , bone deterioration , balance disorders , eyesight disorders , and elevated risk of cancer . Future space habitats may attempt to address these issues, and could be designed for occupation beyond

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780-477: A year, all aboard Mir . Many spacecraft are used to dock with the space stations. Soyuz flight T-15 in March to July 1986 was the first and as of 2016, only spacecraft to visit two different space stations, Mir and Salyut 7 . The International Space Station has been supported by many different spacecraft. The Tiangong space station is supported by the following spacecraft: The Tiangong program relied on

845-523: Is 75  Wh / kg , 60 Wh/dm specific power 220 W/kg. The open-circuit voltage is 1.55  V , the average voltage during discharge is 1.25 V. While the energy density is only around one third as that of a lithium battery , the distinctive virtue of the nickel–hydrogen battery is its long life: the cells handle more than 20,000 charge cycles with 85% energy efficiency and 100% faradaic efficiency . NiH 2 rechargeable batteries possess properties which make them attractive for

910-562: 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. Space stations are made from durable materials that have to weather space radiation , internal pressure, micrometeoroids , thermal effects of

975-428: Is capable of generating nearly 31 Kilowatts (kW) of direct current power. When retracted, each wing folds into a solar array blanket box just 51 centimetres (20 in) high and 4.57 metres (15.0 ft) in length. Altogether, the eight solar array wings can generate about 240 kilowatts in direct sunlight, or about 84 to 120 kilowatts average power (cycling between sunlight and shade). The solar arrays normally track

1040-535: Is not designed for disassembly and must be deorbited as one mass. The Axiom Orbital Segment is a planned commercial segment to be added to the ISS starting in the mid-2020s. Axiom Space gained NASA approval for the venture in January 2020. Up to three Axiom modules will attach to the International Space Station. The first module, Hab One, is expected to be launched at the end of 2026 and will be docked to

1105-702: The International Space Station's solar arrays . Use of this system reduced usage of a shuttle's on-board power-generating fuel cells , allowing it to stay docked to the space station for an additional four days. SSPTS was a shuttle upgrade that replaced the Assembly Power Converter Unit (APCU) with a new device called the Power Transfer Unit (PTU). The APCU had the capacity to convert shuttle 28 VDC main bus power to 124 VDC compatible with ISS's 120 VDC power system. This

1170-586: The Kennedy 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 the Apollo command and service module docking. While never realized, the Apollo command and service module would perform docking maneuvers and eventually become

1235-545: 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 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

1300-574: 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. The duration record for a single spaceflight is 437.75 days, set by Valeri Polyakov aboard Mir from 1994 to 1995. As of 2021 , four cosmonauts have completed single missions of over

1365-570: The energy storage of electrical energy in satellites and space probes . For example, the ISS , Mercury Messenger , Mars Odyssey and the Mars Global Surveyor are equipped with nickel–hydrogen batteries. The Hubble Space Telescope , when its original batteries were changed in May 2009 more than 19 years after launch, led with the highest number of charge and discharge cycles of any NiH 2 battery in low Earth orbit . The development of

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1430-495: The ISS never again required the use of an orbiter's power systems. In December 2006, during mission STS-116 , PMA-2 (then at the forward end of the Destiny module) was rewired to allow for the use of the SSPTS. The first mission to make actual use of the system was STS-118 with Space Shuttle Endeavour . Only Discovery and Endeavour were equipped with the SSPTS. Atlantis

1495-577: The ISS on the SpaceX CRS-8 resupply mission. 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 2   year lifetime it was still attached and being used for storage in August 2022. The space station environment presents

1560-525: The S4 segment, and the 4A power channel and mast can on the P4 truss segments, on 3 and 22 December 2022, respectively. The third pair of panels were launched on 5 June 2023. On 9 June, astronauts Steve Bowen and Warren Hoburg of Expedition 69 installed the fifth iROSA on the 1A power channel and mast can on the S4 truss segment. On 15 June, Bowen and Hoburg installed the sixth iROSA on the 1B power channel and mast can on

1625-500: The S4, P4, S6, and P6 Trusses, consists of 24 lightweight lithium-ion battery cells and associated electrical and mechanical equipment. Each battery assembly has a nameplate capacity of 110  Ah (396,000  C ) (originally 81 Ah) and 4 kWh (14 MJ). This power is fed to the ISS via the BCDU and DCSU respectively. The batteries ensure that the station is never without power to sustain life-support systems and experiments. During

1690-506: The S6 truss segment. The last pair of iROSAs, the seventh and eighth, are planned to be installed on the 2A and 3B power channels on the P4 and S6 truss segments in 2025. Since the station is often not in direct sunlight, it relies on rechargeable lithium-ion batteries (initially nickel-hydrogen batteries ) to provide continuous power during the "eclipse" part of the orbit (35 minutes of every 90 minute orbit). Each battery assembly, situated on

1755-861: The South Pacific Ocean. The Tiangong Space Station ( Chinese : 天宫 ; pinyin : Tiāngōng ; lit. 'Heavenly Palace'), the first module of which was launched on 29 April 2021, is in low Earth orbit, 340 to 450 kilometres above the Earth at an orbital inclination of 42° to 43°. Its planned construction via 11 total launches across 2021–2022 was intended to extend the core module with two laboratory modules, capable of hosting up to six crew. 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. (~23,548 cu ft) (~15892 cu ft) While originally Lockheed Martin

1820-475: The Sun, with the "alpha gimbal " used as the primary rotation to follow the Sun as the space station moves around the Earth, and the "beta gimbal " used to adjust for the angle of the space station's orbit to the ecliptic . Several different tracking modes are used in operations, ranging from full Sun-tracking, to the drag-reduction mode ( night glider and Sun slicer modes), to a drag-maximization mode used to lower

1885-445: The altitude. Over time, the photovoltaic cells on the wings have degraded gradually, having been designed for a 15-year service life. This is especially noticeable with the first arrays to launch, with the P6 and P4 Trusses in 2000 ( STS-97 ) and 2006 ( STS-115 ). STS-117 delivered the S4 truss and solar arrays in 2007. STS-119 (ISS assembly flight 15A) delivered the S6 truss along with

1950-431: The areas of biology and biotech, technology development, educational activities, human research, physical science, and Earth and space science. Nickel%E2%80%93hydrogen battery A nickel–hydrogen battery (NiH 2 or Ni–H 2 ) is a rechargeable electrochemical power source based on nickel and hydrogen . It differs from a nickel–metal hydride (NiMH) battery by the use of hydrogen in gaseous form, stored in

2015-575: 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 the Orbital Piloted Assembly and Experiment Complex after the end of mission is reached for the ISS. However, in September 2017, the head of Roscosmos said that

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2080-566: The battery. Each BCDU can regulate discharge current from two battery ORUs (each with 38 series-connected Ni-H 2 cells), and can provide up to 6.6 kW to the Space Station. During insolation, the BCDU provides charge current to the batteries and controls the amount of battery overcharge. Each day, the BCDU and batteries undergo sixteen charge/discharge cycles. The Space Station has 24 BCDUs, each weighing 100 kg. The BCDUs are provided by SS/L Eighty-two separate solar array strings feed

2145-399: The catalyst and gas diffusion elements, of a fuel cell . During discharge, hydrogen contained in the pressure vessel is oxidized into water while the nickel oxyhydroxide electrode is reduced to nickel hydroxide. Water is consumed at the nickel electrode and produced at the hydrogen electrode, so the concentration of the potassium hydroxide electrolyte does not change. As the battery discharges,

2210-427: The cold void of deep space. Each ISS solar array wing (often abbreviated "SAW") consists of two retractable "blankets" of solar cells with a mast between them. Each wing is the largest ever deployed in space, weighing over 2,400 pounds and using nearly 33,000 solar arrays, each measuring 8-cm square with 4,100 diodes. When fully extended, each is 35 metres (115 ft) in length and 12 metres (39 ft) wide. Each SAW

2275-550: The crewed Shenzhou 10 in 2013. According to the China Manned Space Engineering Office , Tiangong-1 reentered over the South Pacific Ocean , northwest of Tahiti , on 2 April 2018 at 00:15 UTC. A second space laboratory Tiangong-2 was launched in September 2016, while a plan for Tiangong-3 was merged with Tiangong-2. The station made a controlled reentry on 19 July 2019 and burned up over

2340-450: The differential viability of the microbial cells, as a function of phylogenetic lineage, remain elusive. Like uncrewed spacecraft close to the Sun, space stations in the inner Solar System generally rely on solar panels to obtain power. Space station air and water is brought up in spacecraft from Earth before being recycled. Supplemental oxygen can be supplied by a solid fuel oxygen generator . The last military-use space station

2405-487: The early 20th century. In 1929, Herman Potočnik 's The Problem of Space Travel was published, the first to envision a "rotating wheel" space station to create artificial gravity . Conceptualized during the Second World War , the " sun gun " was a theoretical orbital weapon orbiting Earth at a height of 8,200 kilometres (5,100 mi). No further research was ever conducted. In 1951, Wernher von Braun published

2470-400: The expected 30-year life of the station. Each battery measured 40 by 36 by 18 inches (102 by 91 by 46 cm) and weighed 375 pounds (170 kg). From 2017 to 2021, the nickel-hydrogen batteries were replaced by lithium-ion batteries . On January 6, 2017, Expedition 50 members Shane Kimbrough and Peggy Whitson began the process of converting some of the oldest batteries on the ISS to

2535-458: 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. In 1971, the Soviet Union developed and launched the world's first space station, Salyut 1 . The Almaz and Salyut series were eventually joined by Skylab , Mir , and Tiangong-1 and Tiangong-2 . The hardware developed during

2600-403: The first iROSA's successful deployment and connection to the station's power system. The 25 June spacewalk saw the astronauts successfully install and deploy the second iROSA on the 4B mast can opposite the first iROSA. The next pair of panels were launched on 26 November 2022. Astronauts Josh Cassada and Frank Rubio of Expedition 68 installed each one on the 3A power channel and mast can on

2665-450: The following spacecraft. The Mir space station was in orbit from 1986 to 2001 and was supported and visited by the following spacecraft: Research conducted on the Mir included the first long term space based ESA research project EUROMIR   95 which lasted 179   days and included 35 scientific experiments. During the first 20 years of operation of the International Space Station, there were around 3,000 scientific experiments in

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2730-775: The forward port of Harmony , requiring relocation of the PMA-2 . Axiom Space plans to attach up to two additional modules to its first core module, and send private astronauts to inhabit the modules. The modules would later detach into the Axiom Station in a manner similar to Russia's proposed OPSEK. China's first space laboratory, Tiangong-1 was launched in September 2011. The uncrewed Shenzhou 8 then successfully performed an automatic rendezvous and docking in November 2011. The crewed Shenzhou 9 then docked with Tiangong-1 in June 2012, followed by

2795-533: The fourth set of solar arrays and batteries to the station during March 2009. To augment the oldest wings, NASA launched three pairs of large-scale versions of the ISS Roll Out Solar Array (IROSA) aboard three SpaceX Dragon 2 cargo launches from early June 2021 to early June 2023, SpaceX CRS-22 , CRS-26 and CRS-28 . These arrays were deployed along the central part of the wings up to two thirds of its length. Work to install iROSA's support brackets on

2860-401: The hydrogen pressure drops, providing a reliable state of charge indicator. In one communication satellite battery, the pressure at full charge was over 500 pounds/square inch (3.4 MPa), dropping to only about 15 PSI (0.1 MPa) at full discharge. If the cell is over-charged, the oxygen produced at the nickel electrode reacts with the hydrogen present in the cell and forms water; as

2925-410: 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

2990-624: 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 . The first mention of anything resembling a space station occurred in Edward Everett Hale 's 1868 " The Brick Moon ". The first to give serious, scientifically grounded consideration to space stations were Konstantin Tsiolkovsky and Hermann Oberth about two decades apart in

3055-416: The new lithium-ion batteries. Expedition 64 members Victor J. Glover and Michael S. Hopkins concluded the campaign on February 1, 2021. There are a number of differences between the two battery technologies. One difference is that the lithium-ion batteries can handle twice the charge, so only half as many lithium-ion batteries were needed during replacement. Also, the lithium-ion batteries are smaller than

3120-403: The new stations allowed Progress 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 a TKS 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

3185-425: The nickel hydrogen battery started in 1970 at Comsat and was used for the first time in 1977 aboard the U.S. Navy's Navigation technology satellite-2 (NTS-2). Currently, the major manufacturers of nickel–hydrogen batteries are Eagle-Picher Technologies and Johnson Controls, Inc. The nickel–hydrogen battery combines the positive nickel electrode of a nickel–cadmium battery and the negative electrode, including

3250-491: The older nickel-hydrogen batteries. Although Li-ion batteries typically have shorter lifetimes than Ni-H2 batteries as they cannot sustain as many charge/discharge cycles before suffering notable degradation, the ISS Li-ion batteries have been designed for 60,000 cycles and ten years of lifetime, much longer than the original Ni-H2 batteries' design life span of 6.5 years. The power management and distribution subsystem operates at

3315-524: The peak power point of the solar arrays. The thermal control system regulates the temperature of the main power distribution electronics and the batteries and associated control electronics. Details on this subsystem can be found in the article External Active Thermal Control System . From 2007 the Station-to-Shuttle Power Transfer System (SSPTS; pronounced spits ) allowed a docked Space Shuttle to make use of power provided by

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3380-447: 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

3445-466: 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. Space stations are most often modular , featuring docking ports , through which they are built and maintained, allowing

3510-528: The station and perform research. After the supplies had been consumed, the station was abandoned. The first space station was Salyut 1 , which was launched by the Soviet 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 , and Salyut 5 , were also known as Almaz stations. The civilian stations Salyut 6 and Salyut 7 were built with two docking ports, which allowed

3575-533: The sun and cold temperatures for long periods of time. They are typically made from stainless steel , titanium and high-quality aluminum alloys , with layers of insulation such as Kevlar as a ballistics shield protection. The International Space Station (ISS) has a single inflatable module, the Bigelow Expandable Activity Module , which was installed in April   2016 after being delivered to

3640-509: The sunlight part of the orbit, the batteries are recharged. The nickel-hydrogen batteries and the battery charge/discharge units were manufactured by Space Systems/Loral (SS/L), under contract to Boeing . Ni-H2 batteries on the P6 truss were replaced in 2009 and 2010 with more Ni-H2 batteries brought by Space Shuttle missions. The nickel-hydrogen batteries had a design life of 6.5 years and could exceed 38,000 charge/discharge cycles at 35% depth of discharge. They were replaced multiple times during

3705-576: 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. In contrast, the main US modules launched on the Space Shuttle and were attached to the ISS by crews during EVAs . Connections for electrical power, data, propulsion, and cooling fluids are also made at this time, resulting in an integrated block of modules that

3770-503: The truss mast cans holding the Solar Array Wings was initiated by the crew members of Expedition 64 in late February 2021. After the first pair of arrays were delivered in early June, a spacewalk on 16 June by Shane Kimbrough and Thomas Pesquet of Expedition 65 to place one iROSA on the 2B power channel and mast can of the P6 truss ended early due to technical difficulties with the array's deployment. The 20 June spacewalk saw

3835-515: The two groups. Unlike previous stations, the Soviet space station Mir had a modular 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 powerful launch vehicle . Modular stations are also designed from the outset to have their supplies provided by logistical support craft, which allows for

3900-411: The volume efficiency is relatively low (60-100 Wh/L for an IPV (individual pressure vessel) cell), and the high pressure required makes for high-cost pressure vessels. The positive electrode is made up of a dry sintered porous nickel plaque, which contains nickel hydroxide . The negative hydrogen electrode utilises a teflon-bonded platinum black catalyst at a loading of 7 mg/cm2 and

3965-606: The weeks or months that current missions typically last. Possible solutions include the creation of artificial gravity by a rotating structure , the inclusion of radiation 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. 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

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4030-624: 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. As of 2024, they are no longer listed as a partner on Starlab's website. (14,126 cu ft) (29,000 cu ft) 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. A space station

4095-695: Was the Soviet Salyut 5 , which was launched under the Almaz program and orbited between 1976 and 1977. Space stations have harboured so far the only long-duration direct human presence in space. After the first station, Salyut 1 (1971), and its tragic Soyuz 11 crew, space stations have been operated consecutively since Skylab (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

4160-433: Was the only surviving shuttle not equipped with the SSPTS, so it could only go on shorter length missions than the rest of the fleet. Space station 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

4225-523: Was used in the initial construction of the space station to augment the power available from the Russian Zvezda service module. The PTU adds to this the capability to convert the 120 VDC supplied by the ISS to the orbiter's 28 VDC main bus power. It is capable of transferring up to 8 kW of power from the space station to the orbiter. With this upgrade both the shuttle and the ISS were able to use each other's power systems when needed, though

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