Monday, August 14, 2006
In any case the important parts now, since we don't have to worry about terraforming Mars for a while, are Aquarius & Bifrost of which I will reprint the synopses here:
AQUARIUS - Space Colony at Sea
The meat of the plan begins with my favorite step - colonization of the Earth's seas. Aquarius solves todays problems in an inexpensive and ecologically sound way, and serves as a testbed for our later colonization efforts.
The first and most important part of each aquarian colony is an OTEC (Ocean Thermal Energy Converter), a revolutionary form of solar power. Thanks to the sun, surface ocean waters are far warmer than in the depths, especially at the equator. An OTEC is a 3300 foot long pipe that sucks 40 degree (fahrenheit) water to the surface where it's 80 degrees. This temperature differential can then be used to power a steam engine. The lower the air pressure is, the lower the boiling point. At .43 PSI water boils at 80 degrees. The expansion of the water vapor turns a turbine which generates electricity. The vapor then condenses on a pipe that carries 40 degree water, which then lowers the pressure, which causes more water to boil, continuing the process.
A single OTEC will be taken by ship to a spot in equatorial waters, where the water is warm and deep and hurricanes are rare (thanks to the Corriolis force). A magnesium wire mesh will be placed in the water and using the electricity from the OTEC the water will be electrolyzed, creating a "seament". The same minerals used by shellfish to create their shell will be deposited onto the wire from the sea water due to the electricity. After 6 months of electrolysis a 5.5 mile diameter structure capable of housing 100,000 people should be complete.
The OTEC will pay many dividends. Excess energy can be converted and stored, or sold...water can be electrolyzed, separating the oxygen and hydrogen. Hydrogen can then be transported via large balloons for use in fuel cells in other parts of the world. More importantly, the water dredged from the depths of the sea will be rich in nitrogen which will promote plant and algal growth, making sea farming of fish and mollusks possible.
BIFROST - 21st Century Launch System
Our bridge into space will be a revolutionary new system, far more economical than NASA's shuttles. A kilogram of payload onboard a Space Shuttle costs about $8800 to send into orbit. The reason for this is that for every ton of payload (the stuff you actually intend to put into orbit) you have to use 25 tons of fuel and shuttle to get it there (20 tons of fuel, 5 of shuttle). Much of the fuel is spent, not lifting the payload, but lifting the rest of the fuel.
By contrast, Bifrost will be extremely cheap, perhaps as low as $15 to $20 per kilogram over the long term. The reason for this is that the Bifrost shuttle will carry almost none of its own fuel.
Bifrost begins with a 250 kilometer tunnel drilled out of a mountain and the surrounding countryside. The tunnel will be hyperbolic - beginning with a slight upward slope until it reaches the mountain towards the end, at which point it will be nearly vertical. Ideally the mountain will be one situated on or near the equator such as Kilimanjaro because objects at the equator are already moving faster than objects located at other parts of the world...the Earth has a circumference of about 25,000 miles, and rotates every 24 hours, so an object at the equator has an angular velocity of more than 1,000 miles an hour. By contrast, an object at the north pole has nearly no angular velocity. This extra velocity makes launches a bit cheaper (and explains why American launches have been done from Florida and Texas).
The shuttle is a "wave-rider", a delta wing craft (triangular) that coasts on its own shockwave and makes an excellent glider. The wave-rider will be accelerated through the tunnel using superconducting rings in the walls - magnetism will drag it along until it's attained much of the velocity necessary to launch it into orbit.
The wave-rider carries only about 4 tons of fuel. Ice, to be precise. When the wave-rider bursts free of the tunnel, powerful lasers on the ground will vaporize the ice on the rear of the wave-rider, which will give it the extra boost it needs to get into space.
The only fuel needed is a small chunk of (non-polluting) ice, so the electricity needed is rather low.
In particular the idea of an OTEC seems entirely feasible (OTEC - Everything) since it already exists albeit in a smaller form than suggested here. In fact because of the square cube law I would expect a larger variety to be more cost effective. Scotland has a long shipbuilding tradition & still produces some more hi-tech shipping such as oil rigs & a ship designed as a satellite launch site. We could produce Aquarius if we wanted. The main difficulties seem to me political ones (Marshall proposed locating it in international waters off Africa) & that we have a culture where no big project, whatever the economics, will be built if it is not seen as politically correct (eg new nukes). The cost was put in the region of a Â£1 billion, which is a lot (1/3rd of a bullet train) & the economics should be gone into first but it would be a magnificent thing for any nation to do.