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.