...100 MW of Space Solar Power ...per single launch!
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From: Alain Fournier on 17 Dec 2009 19:29 Pat Flannery wrote: > Alain Fournier wrote: > >> >> As I said "there is there is no market for something that doesn't >> exist, so >> there is currently no market for things that are impossible to make on >> Earth. >> >> But I see no reason why >> >>- Alloys made of metals of very different densities. >> >>- Metal mousse (kind of a metal air alloy, or a metal vacuum >> alloy(??) ). >> >>- It is suspected that some crystals next to impossible to grow on >> >>Earth could be made in zero g. >> >> could not be traded in a commercial marketplace. > > Considering the production cost per pound to get the raw materials up to > the space manufacturing facility and the finished product back down to > Earth, you might well trade them like gold or platinum. > These materials would have to do some pretty amazing things to make > their production and use economically feasible. > You could make cars out of titanium and save some pounds as well as > reducing fuel use, but is it worth the added cost and production > difficulty? I agree that it is far from obvious that it could be done profitably. But keep in mind that what was being discussed here is what else could be done with a space based manufacturing capability that is already there (it is there for the purpose of building SPSs). If you already have a mining operation in place on an asteroid, do you shut it down when your last SPS is built? Presumably, you already have solved the most important difficulties about mining an asteroid, maybe the mine is subsurface and miners work without a spacesuit in a breathable atmosphere or the miners are not miners but robots. As for the cost of bringing the stuff down, I suspect you could make heat shields using slag. Even then, I don't consider this an easy business. As I said a few post ago, I wouldn't expect a space based industry to be sending stuff to Earth anytime soon. I would expect a space based industry to be sending fuel and other commodities to LEO or higher up. And to be sending data to Earth, data from huge space built telescopes or what not. Alain Fournier
From: Pat Flannery on 17 Dec 2009 21:31 Peter Fairbrother wrote: > Foamed metal bicycle frames? Foamed metal bicycle frames that cost as much as a house? There actually be a tiny market for something like that though; I know of a guy who discarded his titanium bicycle frame for a carbon-composite one as it was nearly six ounces lighter. :-D Pat
From: Pat Flannery on 17 Dec 2009 21:49 Greg D. Moore (Strider) wrote: > Of course on the economic front, you won't get much of an argument from me. > I've seen nothing to convince me the economics of SPS works in any near-term > future. But the physics, they certainly work. The physics of the whole concept are actually pretty simple and straight-forward. Pat
From: Peter Fairbrother on 17 Dec 2009 20:05 jimp(a)specsol.spam.sux.com wrote: > In sci.physics Peter Fairbrother <zenadsl6186(a)zen.co.uk> wrote: > >> Both 2.45 GHz and 5.8 GHZ are ISM (industry, scientific, medical) bands, >> and aiui are not allowed to be used for communications (part 18, FCC >> rules, as well as international agreements, prohibit this). Otherwise >> microwave ovens would interfere with wifi or cordless phones. >> >> There should be no interference with wifi or cordless phones. > > 802.11 devices run in the 2.4 GHz and 5.8 GHz bands in the US (and most > of the world) under FCC Part 15 as do cordless phones. > > Bluetooth is 2450 MHz. > > HIPERLAN runs at 5.8 GHz. > > Users of Part 15 devices have no legal recourse if a Part 18 emitter > cause interference. Ah. Well that's okay then. You can't get sued :) >> The needed bandwidth is - very small indeed, it's power not >> communications, and could be used by all the satellites worldwide. The >> beam would need to be very monochromatic (within < 0.5 ppm) for >> beamspread reasons anyway. > > For regulatory and practical interference reasons, the frequency would > need to be tightly controlled and would likely require coordination with > the ITU for a globally acceptable frequency to use. As I understand the present situation, internationally speaking you can use 2450 +/- 50 MHz and 5800 +/- 75 MHz for satellite power systems, or for anything else you like. You don't have to do anything, or even tell anyone, you can just go ahead and do it. In practice it might be a good idea to choose a much tighter band, and it's technically necessary for any particular power station anyway. If the ITU want to change things and specify some particular and precise frequency, that's not a technical problem. > Just one more practical hurdle that no one seems to want to talk about. It might be a domestic hurdle, but ... FCC regulations are not a subject I know very much about. I'm not an American :) Actually, I wouldn't describe myself as an expert on space solar power either. But I am a mathematician, and a part-time rocket engineer. -- Peter Fairbrother
From: Alain Fournier on 17 Dec 2009 20:50
Pat Flannery wrote: > Peter Fairbrother wrote: > >> Foamed metal bicycle frames? > > > Foamed metal bicycle frames that cost as much as a house? > There actually be a tiny market for something like that though; I know > of a guy who discarded his titanium bicycle frame for a carbon-composite > one as it was nearly six ounces lighter. :-D That is nothing very special in the cycling world. They sell pedal levers for thousands of dollars, no that's not gold plated pedal levers, its light weight rigid pedal levers. Alain Fournier |