10 Space Station Design Concepts

Modular Space Stations

The space stations of the modern age (Mir, ISS, Tiangong) use a modular design, with several segments (or modules) launched from the Earth and assembled in space. Modules are typically cylindrical in shape, allowing them to be launched inside conventional rockets. It seems likely that all space stations will be constructed in this way for some time to come as it is the most practical solution.

Of course, a modular design doesn’t necessarily mean that a space station is limited in size and complexity. Space stations like the ISS could develop into huge structures, with bigger rockets allowing the addition of bigger modules.

Inflatable Space Stations

One way in which the traditional modular space station design might change over the next few decades is the introduction of inflatable modules. This might sound like a crazy idea, but inflatable designs have already been tested and may soon be put into operation.

Inflatable space station Genesis2The idea of creating inflatable segments was first proposed by NASA as part of their concept for a manned flight to Mars. The TransHab concept consisted of a traditional cylindrical module with an inflatable exterior shell, providing extra living space. The module would have been launched inside a rocket as usual, and would then have expanded once in orbit, inflated by the breathable atmosphere within. The fully inflated TransHab module would be 8.2 meters in diameter (spacious compared with other craft) and contain three levels of leg-stretching luxury.

The TransHab concept was reluctantly dropped by NASA in 2000, but the concept was bought by Bigelow Aerospace, who continued to develop the design. The company has since launched the Genesis I (2006) and Genesis II (2007) modules to test the viability of inflatable space modules. They plan to build their own TransHab space station – referred to as Space Complex Alpha – as early as 2014.

Orbital Tether

Another ambitious idea that has been explored by NASA is the building of an ‘orbital tether’, also known as a ‘space elevator’, ‘space ladder’, ‘space tether’ or ‘skyhook’. This idea has actually been around for a very long time (hence its many names) and has long been considered a practical solution to the problem of transporting materials and personnel into orbit, and refueling spacecraft.

orbital tether

The idea is to connect (or tether) an orbiting space station to the ground. The space station would act as a counterweight, keeping the tether upright. The space station could then be reached by climbing the tether in an airtight elevator car.

Many science fiction writers have played with this idea, including Arthur C. Clarke (in The Fountains of Paradise), but the original credit goes to Russian scientist Konstantin Tsiolkovsky who, in 1895, was inspired by the Eiffel Tower to conceive a tall tower connected to a “castle” in a geostationary orbit.

Orbital Drydock

Drydock space station

The building of an orbital ‘drydock’ (or ‘space dock’) like those seen in Star Trek would seem to be a practical necessity of any space-faring civilization.

The need to build and repair space ships in orbit is likely to grow as we venture farther out into space, as building large craft on the surface and launching them into space becomes impractical. Even modular space craft require some assembly in space. This means more spacewalks and a greater need for robotic arms. A design that surrounds the craft allowing access and inspection from all angles would therefore be advantageous.

An orbital space dock would not only allow the construction of larger spaceships, but of larger space stations too.

Habitation Wheel

This design was first used in 1929, when Austro-Hungarian scientist Herman Potocnik proposed its use for long space voyages. The spinning wheel has since become a staple of science fiction, and is still considered to be the most practical solution to the problem of artificial gravity.

wheel space stationAn enclosed  spinning wheel creates centrifugal force, pushing its contents outward and creating the illusion of gravity. A spinning segment does not need to be a complete circle for the effect to work, but this is the most practical design in terms of floor space. The purpose of the wheel is generally to provide a comfortable living space for the crew.

The idea of using rotation to create artificial gravity dates back to 1903 and Russian scientist Konstantin Tsiolkovsky and it has been something of a scifi revolution. The simple spinning wheel concept has since led to many more interesting designs.

Stanford Torus

The Stanford torus takes the idea of a spinning wheel and applies a much large scale. The design was developed at Stanford University in 1975 as part of a study into potential long-term habitation of space. Unlike smaller wheel designs, the Stanford torus would be a permanent, self-sufficient orbital habitat. Sunlight would bStanford Torus space statione provided by a series of mirrors on the inside of the wheel (shielding against radiation from direct sunlight).

Like other wheel-shaped space stations, the torus features spokes leading to a central ‘hub’ section. As this section would experience the lowest ‘gravity’, it would be the ideal place for ships to dock.

O’Neill Cylinder

Another spinning space station concept is the O’Neill cylinder. The idea was first proposed by American physicist Gerard O’Neill in his 1976 book “The High Frontier: Human Colonies in Space”.

Tubular space station

The O’Neill cylinder works in much the same way as the Stanford torus, except that it is cylindrical rather than wheel-shaped. This provides a larger surface area and more living space within.

Light enters the habitat via three large windows running the length of the cylinder. Three large shutters, one for each window, can be closed to protect the habitat from radiation. While in an open position, the mirrored inner-surface of these shutters reflects light into the habitat, thus protecting it from the harmful effects of direct sunlight. In the picture (right), you can see the sun reflected in the uppermost shutter.

Probably the most famous O’Neill cylinder in science fiction is space station Babylon 5. However, Babylon 5 is not a true O’Neill cylinder as it lacks the reflective radial shutters.

Bernal Sphere

Similar to the O’Neill cylinder, the Bernal sphere is a large rotating habitat with added protection from radiation. If the O’Neill cylinder is Scooby Doo, the Bernal sphere is Scrappy Doo – smaller but twice as tough. While it may not be as efficient in terms of providing comfortable living space, it is much more efficient in protecting against radiation from solar flares. Unlike Scrappy Doo, however, the Bernal sphere is much older than its cousin. It was first proposed in 1929 by British scientist John Bernal. It was later used by Gerard O’Neill in his study at Stanford University, alongside the O’Neill cylinder and the Stanford taurus.

Bernal sphere space station

The central habitat would be roughly spherical in shape to help deflect radiation. This would create a valley of habitable space inside. Light would enter the habitat through windows at either end of the sphere’s rotational axis, reflected by a series of mirrors. This enclosed design would be much less vulnerable to radiation and impact damage than the O’Neill cylinder, though it does lack the design elegance of its counterpart.

As the habitat would be much smaller, a series of agriculture rings were added to either end. These greenhouses would be insulated against radiation by the large amounts of soil they would contain, but they would be considerably more vulnerable than the sheltered habitat of the sphere.

Ringworld

Imagine a giant Stanford torus encircling a star, with a radius equal to the distance between the Earth and the Sun. This is the concept of the ‘ringworld’, first envisioned by Larry Niven in his 1970 novel, “Ringworld“. Niven’s ringworld had an inner surface several million times greater than that of the Earth. The illusion of night and day was created by a series of huge shadow squares positioned closer to the star.

Dyson Sphere

Another idea, similar to that of the ringworld, is the Dyson sphere. In most fictional portrayals, the Dyson sphere takes the ringworld concept and encloses it as a complete sphere, creating a giant hollow globe around the sun. The purpose being to harness vast amounts of solar energy, and to provide huge amounts of living space.

Freeman Dyson, for whom the concept is named, had a different vision however. His concept did not involve building a single spherical mega-structure, but encircling the sun with a series of smaller space stations; a ‘swarm’ or ‘shell’.

Another of Dyson’s concepts has been dubbed the “Dyson net’. It involves placing a large number of huge solar panels in orbit around the sun. The panels would be connected by a ‘net’ of cables to both transfer energy and keep the panels in place.

  • http://wideawakebutdreaming.wordpress.com/ Raymond Frazee

    something Clark brought up in “Fountains of Paradise” and expanded upon in “2061” and “3001”. Once you have orbital elevators in place you can connect them all with an equatorial ring, and that not only gives you a heck of a lot of room to grow, but stabilizes the elevators even more. Because of the size of the structure one can place internal rings producing centrifugal gravity to off-set the zero gee one would feel everywhere else.

    Also two other megaprojects for space: the Globus Cassus, which is where you take Earth apart and turn it into a kind of Dyson Sphere with the ecosystem on the inside, and a Topopolis, which is a long cylinder like an O’Neill colony, only wraps all the way around a star and rotates along its “center line” to produce gravity all along the inside walls.

    • TVG

      The topopolis was described in Larry Niven’s Bigger Than Worlds.

  • http://www.scifiideas.com admin

    Ray. What would you call a ring connecting space elevators like that?

  • http://wideawakebutdreaming.wordpress.com/ Raymond Frazee

    Let me get out “Fountains of Paradise” . . . there doesn’t seem to be any exact name for the formation. Clarke got some of the information of it from a NASA Technical Memorandum TM-75174, “A Space ‘Necklace’ About the Earth”, done by a Dr. Polyakov of the Astrankhan Teching Institute in the (then) Soviet Union.

    Clark also talks just a little about it here, but it seems there’s no real name for it. So I’d call it a “Geostationary Necklace”, since that’s what it would really be.

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    I like the concept of an inflatable space station. Modular space stations are not that bad either.

  • http://tomorrownewsnetwork.com/ James Pailly

    There was an anime movie where they had an artificial ring around the earth connecting four space elevators. As I recall, they just called it the “space ring.”

    • Cassidy Frazee

      That was something Arthur Clark imagined in “The Fountains of Paradise,” and had it play a part in 2061: Odyssey Three.” He admitted that while he was working on the proofs for “Fountains,” someone sent him a paper that a Russian had published in Teknika Molodezhi, describing “The Space Necklace”, as they called it. Clark always like it when those coincidences popped up . . .

  • Steven Lyle Jordan

    The Babylon 5 station from the program of the same name featured a sort of hybrid station: Partly rotated to create artificial gravity; and partly fed by gravity generators in certain areas (though it was not obvious what parts of the interior sets were supposed to be under gravity and what parts were under centrifugal force).

    I always favored the O’Neill cylinder, with two caveats: One, I thought the huge windows were just crazy, as they would essentially allow all solar radiation into the cylinder, not to mention costing you a third of your usable space. Interior artificial lighting is a much better idea.

    Two, everyone on the O’Neill cylinder lives on the inside of the outer shell, leaving a lot of pretty but otherwise unused space above everyone’s heads. If you had inner levels, like cylinders inside of cylinders, you’d have more usable space; and you could vary the rotation of each level to give them the same gravity as the outer level, or progressively lower gravity levels (might be handy for the elderly or infirm), right down to no gravity (for freight areas).

    I used that variation of the O’Neill design in my Verdant Skies novels.

    • http://scifiideas.com/ Mark Ball

      So when you get old and infirm, it’s time for you to go “upstairs”, reaching a “higher level”, and other puns.
      I always imagined B5 was working on a multi-cylinder principal, the outer one being “Down Below”.

  • TVG

    Babylon 5 only used spin gravity, combined with active suspension of disbelief to simulate normal gravity. The Earth Alliance did not have any other artificial gravity technology until they later obtained it from the Minbari. That’s why all the Earth ships have spinning sections except later when the new Excalibur class does away with that.

  • rjschwarz

    I’ve always wondered, in the 2001 style habitation wheel would there be gravity on the interior walls of the hub? The hub is spinning just like the rest of the station after all.

    Also, would it be possible to make a counter-spin section designed to stay still like on Babylon 5 or would the connection between moving parts be to prone to air leakage.

    • Cassidy Frazee

      There would be some, but it’s minimal. The 2001 space station, Space Station V, was 300 meters across and made one rotation every minute, producing a centripetal acceleration of just over .16 g, or what you’d find on the moon. 30 meters from the center point–about 100 feet–the centripetal acceleration is .033 g, or about what you’d find on a good sized asteroid. It’s close to being zero gee without complete weightlessness.

      With various moving part like you’d have on B5 there probably is some air loss, but then there would be some air loss day-to-day, though minimal. All the moving parts probably wouldn’t add significantly to that loss.

      • rjschwarz

        Thanks.

        • http://scifiideas.com/ Mark Ball

          It makes much more sense just to spin the whole station. The area close to the center would be a good place to ‘land’ ships because of the lower gravity, while the outer rim can be used for… squash courts, water polo, pyramid, rollerball, parisses squares, fencing – ya know, all the sports people play in space :)

          • http://scifiideas.com/ Mark Ball

            The cylindrical space station docking areas in Elite Dangerous are a great example.

            • rjschwarz

              Okay, next question as I design my station. You have a spinning station more or less like in 2001 but big enough to provide Mars gravity. Now yank a dome off the Valley Forge in Silent Running and attached like a hubcap on one side of the wheel.

              The idea is open space for recreation, the ability to grow plants (possibly food), and a sunshield to some extent. Originally the idea was the dome and hanger bays wouldn’t spin so that it would be a big zero g section. If it spins perhaps the dome will have have a bunch of mini-wheels/level/walkways instead of a big open area for playing.

            • http://scifiideas.com/ Mark Ball

              Hmm. Sure, if you want a zero-g dome. That seems a little pointless to me (unless you’re playing that game from Ender’s Game).
              I like the idea of wheels within wheels, but it’s probably very inefficient.
              I think a Stanford Torus would suit your needs much better.

            • http://scifiideas.com/ Mark Ball

              Here’s a picture I found a while ago of really poor station design. It made me chuckle.

            • Cassidy Frazee

              Hey, if you don’t mind all your food stuff you’re growing eventually floats up to the top of the glass dome, go for it!

              To me, the O’Neill cylinder design is still the best for maximum living and having breathable null-g area to do things like fly around with real wings. If you want to go smaller, use a Bernal sphere.

              The one thing to watch for in “traditional” rotating stations is the Coriolis force as you get closer to the center of the station. That can mess you up with vertigo pretty fierce if you’re not careful.

            • rjschwarz

              I don’t want anything as big as the O’Neill or Bernal or Bab 5 More of a gateway/port for those going to Earth than a major colony station. Thanks for helping me clear up the vision a bit.

            • Cassidy Frazee

              Checking the Spin Calculator (http://www.artificial-gravity.com/sw/SpinCalc/SpinCalc.htm) to get .4 gs you need a station with a radius of 125 meters (400 feet) so you don’t get too much angular velocity that would mess up your head. If you take it all the way up to a thousand feet across, that gives you plenty of room to add on things, even put four or five levels on your station.

              The Atomic Rockets site has a whole section on artificial gravity (http://www.projectrho.com/public_html/rocket/artificialgrav.php). It’s a good read, and don’t let the math bother you.

          • rjschwarz

            Seems that whole 2001 matching the rotation would be a hassle when landing compared to the way Bab 5 did it.

            • http://scifiideas.com/ Mark Ball

              So far I’ve found it surprisingly easy in Elite, but that’s probably because I’ve got a small ship and because once you enter the bay you start to rotate along with the station (because of air pressure maybe?)