Maybe we don’t have to find a new planet. Maybe we can make one.

From Elysium to Mass Effect to Interstellar, the fantasy of building a habitable space station seems to find its way into any kind of human extraterrestrial expansion. That’s not a coincidence. We’ve had ideas for a floating human colony for decades. NASA even has pictures of them.

While NASA does not have official plans for floating habitations, it does seriously entertain the concept. In the summer of 1975, nineteen professors met for ten weeks at Stanford and the NASA Ames Research Center to put together a comprehensive report determining the feasibility of constructing huge, spinning worlds for a few thousand humans to live on. Today, the designing process lives on as a student challenge. A team of three Bulgarian students just won the grand prize.

The focus of the NASA report was to come up a space habitat where 10,000 people could work, raise families, and live out normal human lives. The structure would orbit between the Earth and the Moon at a Lagrangian point—one of the five points a third object between two orbiting bodies can maintain a constant position—and would be shaped roughly like a bicycle tire. Called a “Stanford Torus,” this bicycle-shaped habitat would house humans on the inside of what would be the tire, with “spokes” holding the ring together as it spun. It has to spin because humans need gravity.

Creating artificial gravity isn’t as easy as flicking a switch—the whole space station has to spin. Spinning a station doesn’t just create gravity, however, it fakes it. Think of it like the carnival ride where riders are pressed up against the wall of a spinning cylinder. If you’ve ever been on one, you know how hard it is to press yourself from the wall when the whole contraption is spinning. Blame inertia. The spinning action wants to fling you out into space, but the walls of the ride get in the way. Fighting each other, the result of these forces is a force on your body pressing you against the sides of the cylinder.

Any space station that wanted to create artificial gravity would be just like the carnival ride—it would spin fast enough to press you against the “floors” of station with the same force as the Earth pull you towards the core. Having the station spin at a certain rate to generate 1G—Earth’s acceleration due to gravity—is the critical part. Every single aspect of human biology has evolved under gravity’s constant tugs. Without gravity, the human body goes haywire. Astronauts lose 1% bone mass or more per month while weightless aboard the ISS.

There are problems with station spinning too. Even if you calculate the perfect spin rate for a station, humans will still get queasy (as unfortunate test subjects have found out) and weird forces will put us off balance. If you were to jump straight up a foot-and-a-half, for example, a “Coriolis force”—a force felt when you move along a different axis on a rotating object (think of trying to run perfectly straight on a merry-go-round)—would put you down two inches from where you leaped.

Despite the potential problems, the basic concept of a spinning space station is sound, and is exactly what filmmaker Neill Blomkamp drew upon for the sci-fi action movie Elysium. But physics aside, building the station would be the hardest part.

A space station would need its own magnetic field to steer away solar and cosmic radiation. It would need to be heated, have a finely tuned atmosphere, and be equipped with a very sophisticated communications system to stay in touch with Earth—its only lifeline. The nearby Moon would have to be mined for oxygen, silica, and materials used in radiation shielding.

For a torus-shaped habitat holding 10,000 humans, the authors of the report suggest “having colonists ship a million tonnes per year by electromagnetic mass launcher to [Lagrange point 2]. There, with the active catcher, the material is gathered and transshipped to [Lagrange point 5] to be refined and processed.” It would be a mammoth undertaking.

With the perils of climate change, overpopulation, and resource scarcity looming, moving a segment of the population into a permanent foothold in the void sounds less like science fiction every day. Let’s hope our own Mass Effect-style “Citadel” won’t secretly be a portal for sentient machines to harvest the galaxy’s organic matter.

Kyle Hill is the Science Officer of the Nerdist enterprise. Follow the geekery on Twitter @Sci_Phile.

IMAGES: NASA Ames Research Center

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