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Keith Henson wrote:
<blockquote
cite="mid:AANLkTinLbbJScERVqWjtc1Q9WfpkZksjze9O-MtuvL4w@mail.gmail.com"
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<pre wrap="">On Thu, Jul 8, 2010 at 6:02 PM, samantha <a class="moz-txt-link-rfc2396E" href="mailto:sjatkins@mac.com"><sjatkins@mac.com></a> wrote:
[sorry for not fixing the subject on the previous reply]
</pre>
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<pre wrap="">I agree that this is a much more immediate energy solution than space
based solar, at least SBSP of any design I am familiar with. The first
problem with SBSP is the huge mass all the mirrors and collectors
represent and the high cost of launch.
</pre>
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<pre wrap=""><!---->
To put numbers on it, for two cent power and a ten year payback, the
cost limit is around $1600/kW (80,000 hr at 2 cents per kWh).
</pre>
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What do you mean by "two cent power"? <br>
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cite="mid:AANLkTinLbbJScERVqWjtc1Q9WfpkZksjze9O-MtuvL4w@mail.gmail.com"
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<pre wrap="">
Though people have been more optimistic, the general consensus is that
5kg/kWh is reasonable.</pre>
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Can you point me to the work? Does it add in a precentage of all
components? <br>
<br>
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cite="mid:AANLkTinLbbJScERVqWjtc1Q9WfpkZksjze9O-MtuvL4w@mail.gmail.com"
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<pre wrap=""> so if parts and ground rectenna cost $1100/kW,
then the transport cost can't be more than $100/kg.</pre>
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Ah, thanks.<br>
<br>
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cite="mid:AANLkTinLbbJScERVqWjtc1Q9WfpkZksjze9O-MtuvL4w@mail.gmail.com"
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<pre wrap=""> That's a 200 to
one reduction from current cost. It's doable (I think) with something
like a Skylon to the point you run out of atmosphere and laser heated
hydrogen from there on up to LEO and a second stage also using laser
heated hydrogen from LEO to GEO. It does take some $60 B of lasers.
</pre>
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<br>
Or perhaps using on of the other non-rocket space launch methods. Are
the $60B of lasers amortized into the cost?<br>
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<pre wrap="">
</pre>
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<pre wrap="">The second is that you have no
way to do all the assembly and maintenance required at GEO. Doing it
with astronauts is a non-starter. We would need a lot better space
robotics than we have.
</pre>
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<pre wrap=""><!---->
Not actually. Supporting 1000 people at GEO to do assembly takes
around 1% of the mass flow to build power satellites. But it doesn't
matter.
</pre>
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Why doesn't it matter? It cost a lot more than mere mass to support
astronauts working at GEO. We don't do much of that now. Not to
mention I doubt we have 1000 suitably trained astronauts. <br>
<br>
- samantha<br>
<br>
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