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Monday, September 29, 2008


The sum of $5 billion to be paid for construction and maintenance of a space station which has been continuously in orbit with at least 5 Americans aboard for a period of not less than three years and one day. The crew need not be the same persons for the entire time, but at no time shall the station be unoccupied.

This is the 2nd X-Prize suggested by Jerry Pournelle, after getting a cheap orbital craft. Of course it need not be Americans, if Britain, or indeed the rest of the world were to get off our collective arses & put under £3 billion aside. Since there is now way we have to pay anything for about 8 years (4 years before the spaceplane can be constructed, 1 year to actually build this & 3 years & a day beyond that.

What does this produce that space station Freedom hasn't. Well pretty much everything since "Freedom" really hasn't done anything but be there. Because it is run by NASA & everything costs 100 time what it should nothing that can be done is financially viable. Things it should have been doing & a private enterprise spacestation that wanted to make money would do are:

Materials testing. The number of materials that can be made in zero G, where light & heavy elements can mix properly exceed, by orders of magnitude, the total that can be made down here. Beyond that it will be possible to make them in different structures than we can. For example in a gravity field if you put bubbles in molten steel they will rise to the top instantly. Where there is no gravity it is possible to create steel girders like aero. Such materials should have 80% of the strength & 10% of the weight of conventional ones. It is my opinion that when we have a true spacegoing civilisation creating materials not possible on Earth will be the greatest industry. Space has tremendous other possibilities - unlimited energy, laboratory condition vacuums & metals, even platinum & gold, & other elements available by the millions of tons from asteroids, but all of these are merely a step up from what we can do on Earth. New materials are something which usually simply cannot be made here & thus have a value which is both potentially unlimited & impossible to know till we have made & tested them.

Satellite emplacement & repair. Once you are in orbit you can take time to get to a different orbit. Taking longer means less fuel & therefore less cost so emplacing new satellites from an orbital station is much easier than putting them up by rocket. it also means they can be assembled in the space station rather than having to be designed to fit in a rocket nosecone. Finally it means that the simpler sort of repairs can be made either on site or by bringing them back to the station. Current satellites have to be designed for having system redundancy & everything being as robust as possible at the expense of other function, simply because they cannot be repaired.

Most satellites are for surveying or communicating with Earth & there is no reason why a much bigger space station cannot engage in this even more successfully. Much of the work can be automated & pictures sent down but when anything unexpected is wanted there is no automated machine that can do as much as a competent human.

In energy terms Earth orbit is "halfway to anywhere in the solar system" as Robert Heinlein said. Interplanetary spaceships will not be designed to land on Earth but will start from & be built in orbit. Your craft has to be aerodynamic to get to orbit but optimum deep space designs will be very far from aerodynamic. This probably applies even to commercial travel to the Moon. A space station is therefore am important stepping stone to the universe & the place where true spaceships will be assembled.

We are well behind where Kubrick thought we could be by 2001 though as you can see he expected that by then the station, though in use, would still be abuilding (though to nitpick if you were going to build a 2nd ring you would build it separately under zero G & then attach it rather than building it while it was attached to & spinning as fast as the first ring).

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