Humans could one day live in Manhattan-sized asteroid megacities

Massive asteroids could one day be home to future space colonizers.

That’s because a team of scientists from the University of Rochester published, what they call, a “wildly theoretical paper” outlining how we could one day use asteroids as massive city-sized space habitats.

The theoretical method involves one large, spinning asteroid and one enormous mesh bag made of carbon nanofibers, a press release explains.

An asteroid city concept based on a 70’s NASA design

The new theory is a twist on the so-called “O’Neill cylinder”, devised by physicist Gerard O’Neill after NASA commissioned him in 1972 to design a space habitat that could allow humans to live in space.

The O’Neill cylinder is a spinning habitat typically made up of two cylinders connected by a rod, rotating in opposite directions. Those cylinders spin just fast enough to create artificial gravity but not so fast as to induce motion sickness.

Science fiction enthusiasts might have recently read about a similar concept used for the titular spacecraft in ‘The Martian’ author Andy Weir’s latest novel ‘Project Hail Mary’. More grandiose and far-fetched concepts exist in various forms in sci-fi, such as in the image below.

The scientists who devised the new method, outlined in a paper in the journal Frontiers in Astronomy and Space, did so as part of a thought experiment. They aimed to think up a space habitat idea that wouldn’t require massive amounts of materials being launched into space.

A Manhattan-sized asteroid space habitat

The idea they ultimately came up with was to use materials already free-flying around space in massive quantities in the form of asteroids.

One problem remained, however. Asteroids are nowhere near large enough to provide enough gravity for a space habitat. What’s more, if they are spun around fast enough to create artificial gravity — as in the O-Neill cylinder concept — they would simply break apart, as they weren’t built and designed to have structural integrity like a spacecraft.

The solution to this problem is where the “wildly theoretical” part comes into play. The scientists posited that future space colonizers could wrap a massive mesh bag made of carbon nanofibers around an asteroid roughly the size of Bennu, which has a 300-meter diameter.

“Obviously, no one will be building asteroid cities anytime soon, but the technologies required to accomplish this kind of engineering don’t break any laws of physics,” explained physics professor Adam Frank, who worked on the project alongside a number of Rochester University students during the lockdown.

They would then rotate the asteroid to the point it breaks apart. All the rubble from the space rock would be caught in the nanofiber mesh, creating a hollowed-out outer layer that could be used as the exterior structure for a space habitat. Crucially, that layer of asteroid detritus would act as a shield against radiation. A cylinder used to spin the asteroid would create enough artificial gravity on the inner surface for a functioning space habitat.

“Based on our calculations, a 300-meter-diameter asteroid just a few football fields across could be expanded into a cylindrical space habitat with about 22 square miles of living area,” Frank says. “That’s roughly the size of Manhattan.”

The space industry is gearing up toward human exploration of Mars and beyond, meaning we will increasingly see the real world of space science and that of science fiction converge.