Restructure An Asteroid, Spin It, Get A 'Space Habitat' With Gravity?
It takes a lot of energy to lift a space station up into orbit. Could we cheat a little by restructuring and spinning an asteroid to get a suitable space habitat?
After a relatively in-depth selection process, Dr. Jensen decided on one in particular as a good candidate – Atira. This S-type asteroid has an entire class of asteroids named after it. Atira comes in at about a 4.8 km diameter and even has its own moon – a 1 km diameter asteroid that orbits it closely.
It wasn't the closest potential asteroid, with its closest approach at about 80 times the distance to the Moon. Still, its orbit is stable in the "Goldilocks zone" of our solar system, which would help stabilize the internal temperature of the habitat it would eventually be turned into.
So what type of habitat should it be turned into? Dr. Jensen looked at four common types – the "dumbbell," sphere, cylinder, and torus. One of the most critical considerations is gravity – or "artificial gravity"- caused by centripetal force. Dr. Jensen mentions the detrimental effects of living in low-gravity situations for long periods, which necessitates using some artificial replacement for it.
But to get centripetal force, the station has to rotate. Atira already has a slight rotation, but part of creating a space habitat would include spinning the asteroid itself up to a reasonable rotational speed that could accurately mimic the gravity a person would feel on Earth.
It was nearly twenty-four hours later that they finally approached their destination, a tiny, five-mile world of solid metal, a part of the nickel-steel core of some long vanished planet. Its surface turned swiftly beneath them, flashing around in moments as they watched, a surface made up of great crags and clefts of metal, broken, barren masses of metal.
“Lord — it would be impossible to establish a city on the surface of that top!” exclaimed one of the Patrolmen. “The centrifugal spin there would throw anything off into space.”
“How about the inside of it then?” asked one of the guards, smiling at him...
"...When the colony was established, the whole interior was carved out with atomic burners — burned the stuff out into gas, and let it escape. The shell’s about half a mile thick. Inside, the centrifugal force gives an acceleration just equal to one earth gravity, we’re up to speed, and you can see we have about an earth-weight away from it now. And an artificial sun gives plenty of light.”