Space station

A space station (or orbital station) is a spacecraft that stays in orbit and hosts humans for long periods of time. It is an artificial satellite with special rooms for people to live in. Space stations are used for many purposes, mostly as research stations, but sometimes for military work or even to welcome space tourists.

Space stations are special because they are the only places where humans have lived continuously in space. The very first space station was Salyut 1 in 1971. Since then, many space stations have been built and used, starting with Skylab in 1973. Today, people have lived in space without stopping since the year 2000, thanks to the International Space Station.

Right now, there are two big space stations that are fully working: the International Space Station and China's Tiangong Space Station. Sometimes, many people can be in space at the same time—up to 13 on one station and 17 altogether! Space stations are usually made in pieces that fit together in space. They have special places where other spacecraft can connect, bringing more people, food, and tools. Even though they stay in the same place, they have small engines to keep their orbit just right.

History

Early concepts

The idea of a space station first appeared in Edward Everett Hale’s 1868 story "The Brick Moon". Later, scientists like Konstantin Tsiolkovsky and Hermann Oberth thought deeply about space stations in the early 1900s.

In 1929, Herman Potočnik’s book The Problem of Space Travel described a “rotating wheel” space station to create artificial gravity. During World War II, there was a idea for a “sun gun”—a theoretical orbital weapon flying around Earth. No more work was done on it. In 1951, Wernher von Braun shared a idea for a rotating space station in Collier's Weekly, but it was never built.

First advances and precursors

First description of a rotating space station, in Hermann Noordung's The Problem of Space Travel (1929).(Legend: Achs-Körper: axle body. Aufzugschacht: elevator shaft. Treppenschacht: stairwell. Verdampfungsrohr: boiler pipe).

Further information: Space rendezvous § First docking

The first person to travel to space was on April 12, 1961, aboard Vostok 1.

Early space station ideas were mostly drawings, but between 1959 and 1961, people built a full-sized model called the Manned Astronomical Research Station to test ideas on Earth. The Apollo program once planned to send people to orbit the Moon and build an Earth-orbiting lab called Project Olympus. But later, the focus changed to landing on the Moon. The Apollo spacecraft later acted like a small station.

The Gemini program helped by completing the first space meetings between ships in 1965 and 1966. In 1966, Neil Armstrong joined two spacecraft for the first time.

In January 1969, Soyuz 4 and Soyuz 5 let astronauts move between ships for the first time, and in March, Apollo 9 did this inside the ships.

Gemini 8 docking with Agena vehicle

Salyut, Almaz and Skylab

Main articles: Salyut, Almaz, and Skylab

In 1971, the Soviet Union launched the world’s first space station, Salyut 1. The Almaz and Salyut series were later joined by Skylab, Mir, and Tiangong-1 and Tiangong-2. These early stations were built all at once and sent to space ready to use. Crews would visit, do research, and leave when they ran out of supplies.

The first space station was Salyut 1, launched by the Soviet Union on April 19, 1971. The early Salyut stations were either for civilians or for the military (called Almaz). The civilian stations Salyut 6 and Salyut 7 could welcome new crews who brought fresh spacecraft. This kept people living there all the time. Skylab, an American station from 1973 to 1979, could also welcome new crews but never used its extra spot for supplies.

Mir

Skylab (1973–1974), the first U.S. space station and second overall

Main article: Mir

The Soviet space station Mir was different. Instead of one big piece, it started with a core and grew by adding new parts later. This made it easier to change and fix, and supplies could fly up regularly.

International Space Station

Main article: International Space Station

Mir station seen in 1998

The ISS has two main parts: the Russian Orbital Segment and the US Orbital Segment. The first piece, Zarya, flew in 1998.

Russia’s parts could fly, find the station, and connect themselves without people. America’s parts were brought up by the Space Shuttle and connected by astronauts.

Axiom Station is a new commercial space station planned to start as a piece attached to the ISS. Axiom Space received approval in January 2020. The first piece, called the Payload Power Transfer Module, may fly to the ISS as early as 2027.

Tiangong program

Main articles: Tiangong space station and Tiangong program

China’s first space lab, Tiangong-1, flew in September 2011. An uncrewed ship called Shenzhou 8 joined it automatically in November 2011. Then, crews from Shenzhou 9 in June 2012 and Shenzhou 10 in 2013 visited Tiangong-1.

Tiangong-1 fell back to Earth over the South Pacific Ocean in April 2018. A second lab, Tiangong-2, flew in 2016 and also fell back safely in July 2019.

The Tiangong Space Station began with a core piece launched on April 29, 2021. More pieces were added in 2022, letting six people live there. The station finished growing on November 5, 2022.

Architecture

Space stations can be built in two main ways: as one big vehicle launched all at once, or as many smaller pieces launched separately and joined together in space. Building stations in pieces is now preferred because it costs less and gives more flexibility.

A space station is a very complex machine. It needs many different systems to work together, such as structure, power, temperature control, navigation, computers, life support, and places for crew members. The station must also serve a useful purpose, which helps decide what features it needs.

Space stations are made from strong materials like stainless steel, titanium, and aluminum alloys. They also have special layers of protection to shield against space radiation, tiny space rocks, and extreme temperatures.

The International Space Station has one special inflatable module that was added in 2016. This module was folded up for launch and then expanded once it reached the station, creating extra space to store things.

Living in space brings many challenges. For short trips, astronauts must manage air, water, food, and waste heat. For longer stays, problems like muscle loss, bone weakening, balance issues, eyesight changes, and higher cancer risk can occur. Future space stations might use artificial gravity, radiation shielding, and even grow their own food to help solve these problems.

Most space stations get their power from solar panels, just like other spacecraft close to the Sun do.

Space stations recycle air and water brought from Earth. Extra oxygen can be made using special generators.

Occupation

Space stations are special places in space where people can live for long periods. The first space station was Salyut 1 in 1971, followed by Skylab in 1973. Since then, people have lived on space stations without stopping. The ISS, which started in 2000, has had the most people at one time—13 people together in 2009.

The longest someone has stayed in space on one trip is 437.75 days. This record was set by Valeri Polyakov aboard Mir from 1994 to 1995.

Operations

Resupply and crew vehicles

Main articles: List of crewed spacecraft and Comparison of space station cargo vehicles

International Space Station

Main articles: List of human spaceflights to the International Space Station and Uncrewed spaceflights to the International Space Station

The International Space Station has been helped by many different spacecraft.

Future
- Sierra Nevada Corporation Dream Chaser
- Roscosmos Orel
Current
- Northrop Grumman Cygnus (2013–present)
- New Space-Station Resupply Vehicle (HTV-X)
- Roscosmos Progress (multiple variants) (2000–present)
- Energia Soyuz (multiple variants) (2001–present)
- SpaceX Dragon 2 (2020–present)
Retired
- Automated Transfer Vehicle (ATV) (2008–2015)
- H-II Transfer Vehicle (HTV) (2009–2020)
- Space Shuttle (1998–2011)
- SpaceX Dragon 1 (2012–2020)

Tiangong space station

Main article: Tiangong space station

The Tiangong space station is helped by the following spacecraft:

Shenzhou (2021–present)
Tianzhou (2021–present)

Tiangong program

Main article: Tiangong program

The Tiangong program used the following spacecraft.

Shenzhou program (2011–2016)

Mir

Main articles: List of human spaceflights to Mir and List of uncrewed spaceflights to Mir

The Mir space station was in space from 1986 to 2001 and was helped and visited by the following spacecraft:

Roscosmos Progress (multiple variants) (1986–2000) – An extra Progress spacecraft was used in 2001 to bring Mir down from space.
Energia Soyuz (multiple variants) (1986–2000)
Space Shuttle (1995–1998)

Skylab

Space Shuttle Endeavour docked to the ISS in 2011 (as viewed from Soyuz TMA-20)

Main article: Skylab

Apollo command and service module (1973–1974)

Salyut programme

Main article: Salyut programme

Energia Soyuz (multiple variants) (1971–1986)

Docking and berthing

Main article: Docking and berthing of spacecraft

Maintenance

Research

Main article: Scientific research on the International Space Station

Research on the Mir included the first long-term space-based ESA research project EUROMIR 95, which lasted 179 days and included 35 scientific tests.

During the first 20 years of the International Space Station, there were about 3,000 scientific tests in areas like biology, technology development, learning, human health, physical science, and Earth and space science.

Materials research

Space stations are great places to test how materials work in space. This research continues from earlier tests like the Long Duration Exposure Facility, which flew from April 1984 until January 1990.

Mir Environmental Effects Payload (1996–1997)
Materials International Space Station Experiment (2001–present)

Human research

Main articles: Effect of spaceflight on the human body and Bioastronautics

Botany

Main article: Astrobotany

Space tourism

Main article: Orbital space tourism

On the International Space Station, guests sometimes pay $50 million to spend a week living as an astronaut. Later, space tourism may grow once launch costs go down enough. By the end of the 2020s, space hotels may become more common.^{[citation needed]}

Finance

Sending things into space is very expensive, costing between $10,000 and $25,000 for each kilogram. Because of this high cost, only government space agencies can afford to build and run space stations. These agencies get their money mainly from taxes. For example, the International Space Station also gets a small amount of money from space tourism.