...100 MW of Space Solar Power ...per single launch!
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From: Sylvia Else on 16 Dec 2009 19:06 Dr J R Stockton wrote: > In sci.space.history message <00851e07$0$16793$c3e8da3(a)news.astraweb.com >> , Tue, 15 Dec 2009 11:55:56, Sylvia Else <sylvia(a)not.at.this.address> > posted: >> Yes, and if the transmitter could run at the temperature of the surface >> of the sun, there'd be no problem. > > > We know that a body at Earth's distance from the Sun, heated by solar > radiation and cooled by its own natural radiation, has an equilibrium > temperature of about (a little below?) the melting-point of ice. (The > Earth is such a body, but has an atmospheric greenhouse effect making > the surface warmer.) Did you overlook the fact that half the Earth is in darkness at any one time? > > Such an object that is transmitting a large portion of the incident > energy as microwaves to Earth must necessarily tend to run cooler than > that, overall. Did you overlook the fact that the transmitter is not the part of the system that's receiving the solar energy because they have different orientation requirements? > > The transmitting components themselves will dissipate heat, and must be > cooled; but it is only necessary to transfer that heat to the rest of > the structure. The components will be distributed across the structure, > so the transfer should not be unduly difficult. Did you overlook the fact that that imposes requirements on the area of the structure. Did you overlook the fact that that imposes requirements on the thermal conductivity of the structure, and therefore the materials from which it is made? > > Perhaps you do not have a background in the physical sciences? > Perhaps you're not as clever as you think you are. Sylvia.
From: Jonathan on 16 Dec 2009 20:05 "Sylvia Else" <sylvia(a)not.at.this.address> wrote in message news:00a54b65$0$23681$c3e8da3(a)news.astraweb.com... > Dr J R Stockton wrote: >> In sci.space.history message <00851e07$0$16793$c3e8da3(a)news.astraweb.com >> Perhaps you do not have a background in the physical sciences? >> > Perhaps you're not as clever as you think you are. > .....replies Sylvia, as she attempts to toss her cognac in the face of the rude dinner quest. But he stops her just in time, their hands now locked in anger, their eyes engage, and as suddenly the crescendo is transformed into two coequal legacies. An anger with no boundaries, and a lust as capacious as the sea. With Elysium now only as far as to the very nearest room. The opening of a door, felicity or doom?
From: Jonathan on 16 Dec 2009 20:21 <jimp(a)specsol.spam.sux.com> wrote in message news:ls1mv6-hrf.ln1(a)mail.specsol.com... > In sci.physics Jonathan <Home(a)again.net> wrote: >> >> "BradGuth" <bradguth(a)gmail.com> wrote in message >> news:6b4a5e28-24e8-423a-89d4-94a3d2e10e6a(a)x5g2000prf.googlegroups.com... >> >> >>> 64% all-inclusive efficiency isn't half bad, >> >>> Getting so much created, deployed and serviced is likely going to >>> consume most every megawatt of energy it produces, and then some. >> >>> Is this energy going to cost us $1/kw.h? >> >> It doesn't really matter, the greater benefit would be >> the effect on all other energy sources. > > Yes, it does, and a lot. > > The cost of electricity increasing by a factor of around 5 would be > an economic catastrophe. > The initial costs are not so important, what counts is the new /trend/ that would be established. Space Solar Power would be very expensive at first, but over time would become steadily ...cheaper... and more ...plentiful. Adding clean energy into the mix. The trend with fossil fuels is ....exactly...the reverse. More expensive and harder to find over time, while adding more and more dirty ...coal...into the mix. Reversing that trend is an absolute necessity. s
From: Alain Fournier on 16 Dec 2009 20:45 Another possibility than having super lift capabilities from Earth is to go for a space based economy. Build the SPSs from asteroid material. I'm not saying that this would clearly be cheaper. But it would be worth evaluating the possibility. I suspect that for a single SPS, launching it from Earth would be cheaper, but if you want to build several, I don't know. Alain Fournier
From: Peter Fairbrother on 16 Dec 2009 21:19
Alain Fournier wrote: > > Another possibility than having super lift capabilities from Earth > is to go for a space based economy. Build the SPSs from asteroid > material. I'm not saying that this would clearly be cheaper. > But it would be worth evaluating the possibility. I suspect that > for a single SPS, launching it from Earth would be cheaper, > but if you want to build several, I don't know. Up to the level of enough manufacturing capacity to supply the Earth's present energy needs, it's still cheaper to make the parts on Earth and lift them, assuming something like the systems I described (and that's true even if they cost a whole lot more than I estimated, it's quite a bit cheaper). However there would be other benefits to starting a space-based economy, for instance things can be made in space which are impossible or expensive to make on Earth - and in the longer-term it's a no-brainer, energy and materials are available in much greater abundance than on Earth, which we don't want to mess up too much with mining etc. Earth should be a good place for people, and that means heavy industry should be located elsewhere, as wherever it is done usually tends to be less hospitable. -- Peter Fairbrother |