Most writers about space colonisation assume we settle the Moon/planets, or else assume some sort of “warp drive” gets us beyond the solar system. That’s either not appealing or just wishful thinking. The only planets suitable for colonisation are Mars, and the Moon, both airless or close to it, and if there is water it is at desert levels. Spending a long time (let alone a lifetime) in low gravity does nasty things like osteoporosis. Most to the point, they are small places: they could not absorb a large number of colonists. As for faster than light, that may be restricted to a few Swiss neutrinos (but I doubt it even there).
The inspired conceptual breakthrough was made by in the 70s, and had quite a run for a time. Don’t try to live on planetary surfaces, but build space habitats . Not little space stations, but potentially huge structures able to house and support millions (and thus with a large area of farmland). They would need to rotate to provide artifical gravity. Various shapes were proposed, including cylinders and toruses. An artist’s impression of the interior of a large cylinder colony is shown below. Mirrors would focus the sun’s rays to provide light and control heat. .
Is it feasible, in the sense of construction, materials and life support? In terms of known modern science and possible materials, yes:
1. Raw materials need to be collected from space: both the gravity well of the earth and environmental issues prevent them being exported from Earth. Key raw materials are water (as such, or as hydrogen and oxygen), iron, aluminium, oxygen, silica, carbon, nitrogen. All of them are available in quantity, but in some cases as far away as the gas giants. This would require a fleet of unmanned cargo collectors, but that is just working capital; the energy required to move something in space is quite modest, with no gravity or air resistance, just the inertial mass of the vehicle itself.
2. You need a prodigious amount of energy to power such a colony but that should be no problem – the sun shines 24/7 at unclouded power out there, and nuclear waste is not an issue.
3. Cybernetic control systems are already well developed, let alone future improvements.
4. A strong magnetic field (an artificial Van Allen belt) plus shielding protects from cosmic rays and micrometeorites.
Because of the earth’s gravity well you need a less primitive and wasteful way of getting people off the earth than rockets, but there are other potential technologies such as the and.
Who wants to live in a rotating tin drum in the depths of space? It would strike many as bizarre, but the mileage that O’Neill’s idea created seems that many were inspired by it. After all, most of us live in highly artificial environments – not just the city, but even the countryside around me is man made. Why we should do so, and why we are no nearer setting up such colonies than forty years ago, another post as this one is already too long and it’s getting late.
