Space Stations
- 8th Nov 2023
- Author: Ed Turner
An outpost in space
Even before humans had made it to space, there were several early concepts of space stations, starting in 1869 when Edward Hale devised a station made entirely of brick. Several more ideas were generated in the 20th century, including rotating ring stations that could create artificial gravity, as well as giant orbital weaponry to aid with the Second World War. Real space stations are a little simpler than these early concepts, though in my opinion much more impressive.
What are space stations?
In the early days of spaceflight, agencies pushed the envelope of how long humans could stay in space, with both the Soviet Union and the USA continuously one-upping each other for the spaceflight duration record.
Issues that astronauts run into when attempting to live in space for extended periods of time is the number of resources required to keep them alive in the inhospitable environment of space. They require oxygen, food and water to stay alive, as well as a way to generate electricity, maintain air pressure in the capsule, and get rid of waste. Not only this, but the cramped conditions of a space capsule leads to psychological and physical issues that can be detrimental to the mission.
Space stations solve this issue by providing large habitation modules for multiple crew members that can be resupplied multiple times to ensure their continuous occupation. The space station Mir allowed the spaceflight record to skyrocket to almost 438 days by Varleri Polyakov from 1994 to 1995.
Space stations provide a unique microgravity environment that can benefit us on Earth, including through drug synthesising and disease research. Not only this, but the operation of craft such as the International Space Station has required the invention of new technology such as water purification systems, which can be used by regions where fresh clean drinking water is sparse. Space stations also provide a similar environment for astronauts that they would experience in long duration flights to other planets.
Space Stations of the past
Early space stations were dangerous, experimental, and often had mission-ending failures. The Soviet Union were the first to successfully put a space station in orbit around the Earth as part of their Salyut programme, Salyut 1, in 1971. Each of the seven Salyut stations were propelled into space in one launch and hosted a crew for anywhere between two weeks and two months at a time until the programme ended in 1986. Mir took the title for first modular space station when the first module was launched in 1986. Mir was not visited only by Soviet cosmonauts, however, as it hosted astronauts from several different countries including British astronaut Helen Sharman, as well as American astronauts across ten space shuttle missions.
Not to be out done by the Soviets, NASA launched their first space station on the 14th May 1973 aboard the last Saturn V. This station, named Skylab, was made from the repurposed third stage of the Saturn V as what was known as a ‘dry workshop’, giving Skylab a huge habitable volume. Each of the three crews to visit the station set a new spaceflight duration record, with the final crew occupying the station for 84 days. When Skylab re-entered Earth’s atmosphere on 11 July 1979 it scattered debris across Western Australia, leading the Australian government to jokingly fine NASA A$400.
Most recently, the Chinese National Space agency, CNSA, have begun to send up their own space stations. Tiangong 1 and 2 were similar in concept to Salyut and Skylab, and were sent up in 2011 and 2016 respectively. CNSA used Tiangong 1 and 2 as a testbed for technologies and techniques to be used on the future Tiangong Space Station.
Current space stations
As of 2023 there are two space station in orbit: The International Space Station and the Tiangong Space Station. While the ISS is a collaborative effort by five space agencies from 15 countries, Tiangong is operated solely by CNSA.
The first module of the ISS was launched in 1998 and took over 40 flights to completely assemble. Since the first long duration stay began in November 2000, over 250 people have visited the station, with many of them completing multiple missions. The ISS is the most expensive thing ever built, with a total cost of $150 billion in 2023. Both Russia and the USA have expressed an intent to move funding away from the aging ISS, with Russia concentrating on their own space station and NASA shifting focus to the Artemis Programme. This means in 2031, the ISS will be deorbited and crashed into the Pacific Ocean, bringing to an end to one of the most incredible spaceflight missions in history.
The Tiangong space station is made up of three modules, though CNSA have hinted that they intend to expand it in the future. Tiangong is China’s first long-term space station, and has approximately one third of the habitable space that the ISS has. CNSA hope to gain experience with operating a spacecraft for long periods of time with permanent human occupation, as well as perform a variety of experiments unique to a microgravity environment, including fluid physics, atomic physics, and biological studies.
Life aboard these two space stations is very similar, though there are some differences reflected in by the age difference of the two. Astronauts must exercise for around two hours every day, perform scientific experiments, and perform maintenance. Astronauts on the ISS are finding an increasing amount of their time is being spent maintaining the aging modules, some of which have been in space for 25 years, whereas minimal time is required for maintenance on Tiangong.
Future space station concepts
The next decade will see the launch of several new stations from agencies around the world, including from NASA, Russia, as well as the first Indian space station. While Russia and India seem to be focusing on low Earth orbit, NASA have set their sights on the Moon.
As part of the infrastructure required for the Artemis Programme, NASA will create what they are calling Gateway. Astronauts will launch to lunar orbit aboard the mighty SLS and rendezvous with Gateway. During the mission, some of the astronauts will remain on the space station in orbit while the rest make the journey down the lunar surface, similar to the Apollo missions.
Private space stations
With the decommissioning of the International Space Station looming, NASA are looking to commercial companies to fill the void it will leave. In March 2021, NASA announced the Commercial LEO Destinations programme, which will help fund the design and development of space stations owned and operated by private companies, which NASA and other space agencies can then send their astronauts to.
As of 2023, these funds have led to two space stations under development. Nanoracks and partner Airbus were granted $160 million to create its Starlab Space Station project, and Blue Origin along with Sierra Space were granted $130 million to create its Orbital Reef project.
On 28 February 2020 NASA awarded a contract to Axiom Space to build a space station in low Earth orbit. What makes this contract so lucrative is that Axiom can build their station onto the ISS before it is decommissioned, allowing them to utilise the existing ISS infrastructure and power systems. Axiom Station will then undock and float freely in space.
While private space stations offer a cheap way for agencies to access space, they also open the possibility for ordinary people to experience space for extended periods of time, though of course ordinary people with deep pockets.
Full references / credits:
(Banner image) The International Space Station orbiting above the Earth. Credit: NASA
(1) Space Shuttle Atlantis docked to Mir in 1995. Credit: NASA
(2) Skylab imaged by the departing crew of Skylab 4. Credit: NASA
(3) An artist’s impression of the Tiangong space station in its final configuration.
Credit: Shujianyang CC BY-SA 4.0 DEED (https://en.wikipedia.org/wiki/Tiangong_space_station#/media/File:Chinese_Tiangong_Space_Station.jpg)
(4) An artist's impression of Lunar Gateway symbolically placed between the Earth and Moon. Credit: NASA
(5) The Axiom Station will serve as humanity’s central hub for research, manufacturing, and commerce in low Earth orbit (LEO). Credit: © Axiom Space
