Wednesday, 2 March 2016

Building Vast Colonies in Space

We should, at the very least, have an orbiting and functional prototype of something like this by now:

Kaplana One Space Settlement - design study in the early 2000s
Pictured above, the Kaplana One Space Settlement is a 500-metre diameter habitat designed to accommodate around 3,000 people on its inner surface. Inhabitants would experience simulated gravity the same as Earth's when Kaplana is spun up to about two revolutions per minute. The interior would consist of large open spaces with grassland and lakes as well as housing, creating a very pleasant environment to live and work. It's a remarkable design, and could be built with existing technology.

Kaplana One Space Settlement - interior
The first Kaplana space settlement will be an enclave of the super-rich, judging from its design. And that’s fine – it’s a great way to recover initial development costs, and a way to generate interest in developing an interplanetary economy, rather than space being nothing more than a place for scientists. It will also encourage the general population to view living in space as desirable rather than as something to be endured.

Asteroid mining is likely to be the first economic activity beyond the confines of the Earth. And such mining will be needed to construct space settlements.

Moving an asteroid ready for construction activity
The second Kaplana-style settlement is likely to be a comfortable accommodation centre for asteroid mining staff. Instead of the spacious homes, gardens, golf courses and lakes of the first one, there are likely to be multi-story accommodation blocks (and individual houses for senior staff, perhaps). The accommodation would still be spacious compared to anything the first asteroid miners are likely to experience, and there would be plenty of recreation space. And, of course, the simulated Earth gravity would keep the mining staff healthy and strong. Such a settlement would be hugely preferable to cramped and almost zero-g habitats on the surface of asteroids.

Construction of a space settlement for asteroid miners
It’s quite possible that if the first Kaplana-style space settlement is successful that most of the initial decades of asteroid mining activity (even centuries) is devoted mainly to building such desirable off-world habitats, and the infrastructure that goes with it (luxurious transportation from and to Earth, supply routes with essentials such as water, microwave power transmission etc.)

It may be that there will be very little interest in building habitats on planets and moons in the Solar-System. Space habitats may well become the preferred places for humans to settle, and become the best means to preserve our species. One of the main reasons for this will be the relative ease at which Earth gravity can be simulated. Simulating such gravity on the Moon, Mars, or any of the other solid worlds in our Solar System would be almost impossible. Long-term colonists on those worlds, and especially their offspring, would be doomed to remain there, their weak bodies unable to cope with a gravity environment even half that of Earth.

With this in mind, the best way for humans to explore the surfaces of our Solar System's planets and moons would be for mobile Kaplana settlements to visit those worlds and for short excursions to the surface to take place. Permanent bases could, and should, be built, but the crews should be rotated on a regular basis so they could return to a comfortable, spacious and high gravity environment. This would ensure that their physical and mental health was maintained. With a permanent route with numerous Kaplana settlements journeying out to Mars, the asteroid belt, Jupiter, Saturn etc., and then back to Earth, miners, scientists and others could make the journey (albeit over many years) in comfort and relative safety, disembarking to surface colonies for a while, and the leaving to join the next Kaplana settlement that comes by. Or, they could return to a settlement that is in permanent orbit for a month or two to recover their strength before returning to the surface. Smaller spaceships, with torus-style rotating sections, could be used for the shortest routes, such as the one below:

A small spaceship with rotating sections - ideal for shorter resupply routes e.g. to the Moon or Mars
Building such a network of Kaplana-style space settlements does seem to be one of the best ways to ensure the short term survival of our species.

Of course, for longer term survival (millions of years instead of thousands) interstellar ships will be required to colonise other star-systems. The design of such ships would benefit greatly from the lessons learned while constructing Kaplana-based settlements. No matter how long the voyage, a gravity environment is essential if the generation that will make planet-fall is to have the best chance of success. Indeed, even a super-Earth, with it's high gravity, could be colonised if the spin rate of the interstellar ship was slowly increased during the voyage to simulate the conditions on the target planet. The humans on board would adapt to the higher gravity well before their destination is reached.

Until a suitable planet is found with conditions almost matching the Earth, living in such space settlements does seem to be the next best thing.

Kaplana is an improvement on some space settlement designs drawn up in the 1970s. They were impressive studies, particularly the Bernel Sphere, a 500 metre diameter sphere for up to ten-thousand inhabitants (actually first proposed in the 1920s), the O'Neill Cylinder, an 8-kilometre wide and 32-kilometre long cylinder, and last but not least the Stanford Torus, an almost two-kilometre diameter ring.  All would rotate to simulate Earth gravity.

O'Neill Cylinder - one of the impressive space colony designs of the 1970s
I know I'm restating a point here, but it's remarkable that not even a small test version of any of the designs has yet been built.  They are all possible with today's technology, and any one of them would be an ideal first step to ensuring the continuation of our species when the inevitable global extinction-level event consumes life on Earth.