If you’ve ever been interested in outer space, you’ve probably heard of the International Space Station (ISS). The ISS is a collaborative effort between the USA, Canada, Japan, Russia and the European Union. It orbits the earth and serves as a base for crews of astronauts and cosmonauts in space. While the research conducted aboard the ISS is incredible, it is also interesting to consider the design of the ISS and other space stations like it. What are the limitations that constrain the construction of a space station? What precautions are undertaken during construction to ensure the safety of later astronauts who use the facility? How does the architecture of the handful of space stations currently in orbit vary?
Image 1_The ISS in 2019_©NASA Space Station view (49882314162).jpg
Keep reading this article to learn the answers to these questions and more about the architecture of space stations.
The evolution of Space Station Architecture over time
image 2_Earth Seen from the ISS, NASA_©https://upload.wikimedia.org/wikipedia/commons/a/a5/Space_Station_view_%2849881484683%29.jpg
In his paper “Design of the Space Station Habitable Models”, Gary H. Kitmacher provides a brief history of the design of space stations. He mentions early in his paper that the primary consideration for early space station design was “orbiting the maximum habitable volume for the lowest cumulative launch costs”. Indeed, space stations needed to be large enough to accommodate living facilities and research labs while retaining space for essential electronics and navigational controls. However, it also quickly became apparent that their total size and weight would be beyond the payload of any existing single rocket launch. Accordingly, space station design became modular. Beyond reducing launch costs by moulding to existing technology, this allowed individual components of a station to be both manufactured and rigorously tested on earth before being launched into space (Kitmacher, 2002).
Image 3_Skylab and Saturn V Diagram_NASA_©1535px-Skylab components in launch configuration.jpg
The first space station to follow this idea was the US’s Skylab, which was a modified section of the existing Saturn V rocket. The experience of astronauts aboard Skylab proved invaluable, as they later advised on the design of the ISS as well. Their insights revealed that it is necessary to have a local architectural directionality of up and down within the space. Within this local directionality, astronauts floating in zero gravity found themselves more often moving from side to side rather than up and down, similar to how they would move on the earth. Another interesting consideration revealed from their experience was the idea of open spaces versus closed spaces. Astronauts described preferring to spend time in their more closed living quarters, where they did not need to worry as much about their items escaping from them and being difficult to retrieve in a large room. These were both important considerations taken into account during the design of the International Space Station. However, Skylab ended up being a one-piece design, making modular design a feature for future stations (Kitmacher, 2002).
Image 4_The International Space Station_©Wikipedia Commons 480px-The station pictured from the SpaceX Crew Dragon 5 (cropped).jpg
Based on the findings from the Skylab experience, the US’s design for the ISS was developed over almost thirty years. The design was based on modular sections (each the largest it could be for a single rocket launch to reduce the number of modules needed for the station), and they maintained a consistent local architectural sense of up and down. While there was a strong debate on whether to vertically or horizontally configure the modules, the eventual design for the station primarily relies on horizontal modules. This modular design was also based on a concern for safety in regards to meteor strikes on the station. As such, a suggestion was made that each module had multiple exit and entry points to enable easier access during a crisis, and ease in travel.
Accordingly, this meant that the structure of the ISS became long, tubular module sections connected by nodes that contained “berthing ports”, or doors to other modules. These nodes also served as storage for on-board systems, freeing space within the modules. The use of nodes also allowed for the modules to grow longer, reducing the number of modules required and improving costs. Overall, the design of the ISS was a cumulative effort through decades of research and refinement. Yet, the core tenets of its design remain the same from the beginnings of space stations in Skylab (Kitmacher, 2002).
Beyond the ISS: Other Space Stations in Orbit
Image 5_Rendering of Tiangong Space Station as of July 2022_©Shujianyang Tiangong Space Station Rendering 2021.10.png
Aside from the ISS, China also operates a space station. Their station, Tiangong, is a relative newcomer, only beginning in-orbit assembly in 2020. The structure is still not entirely complete. The station also relies on a modular design like the ISS; however, one major difference is the presence of a key central module for this design (the ISS chose to avoid this in case of a situation where an inability to access the central module would impair the ability to use the station). Tiangong’s focus will remain on research, with two laboratories attached to the two ends of the central module of the station. Currently, only one laboratory – named Wentian – is attached to the station and in operation. The second laboratory – named Mengtian – is planned for launch in October of 2022, and a telescope is planned for launch in 2023 (Tiangong Space Station – Wikipedia, 2022).
Image 6_The ISS and Earth_©NASA, 2560px-International Space Station after undocking of STS-132.jpg
The architecture of a space station is contingent on a variety of factors. From cost to weight, resilience to redundancy, every aspect of the design of a space station is a fascinating example of how the necessity of function can shape a structure’s form in totality. While space station architecture has already reached a peak, it is unquestionable that further development in this field will yield new design ideas that could facilitate longer, manned space exploration.
References:
- En.wikipedia.org. 2022. Tiangong space station – Wikipedia. [online] Available at: <https://en.wikipedia.org/wiki/Tiangong_space_station#Planning> [Accessed 24 July 2022].
- Kitmacher, G., 2002. DESIGN OF THE SPACE STATION HABITABLE MODULES. [ebook] Houston. Available at: <http://www.spacearchitect.org/pubs/IAC-02-IAA.8.2.04.pdf> [Accessed 24 July 2022].
