[ExI] The L5 Society ( was: EP and Peak oil.)
hkhenson at rogers.com
Thu Apr 10 20:04:17 UTC 2008
At 10:31 AM 4/10/2008, you wrote:
>"Keith Henson" <hkeithhenson at gmail.com>
> > I just finished working out the numbers for using 200 times reusable
> > rockets about twice the size of a Saturn V. To my surprise the energy
> > payback works out to 15 days and it takes 3 power sats to provide the
> > propellants.
>That is a perfect example of a statistic
It's not a statistic. I.e., it does not derive from statistical data.
>that may be true but is totally
>irrelevant; the fuel costs are a trivial aspect of the cost to get into
That's true at present, but in a mature system it would not be
true. Ask the airlines what part of their costs is fuel.
>Right now just the launch costs would be close
>to a trillion dollars per satellite,
Which is why it isn't being done.
>that's just to put it in the proper
>place, and that's not counting on the fact that then you've still got to
>actually build the thing.
Big they are, complicated they are not.
>You're going to have to figure out a way that
>is one hell of a lot cheaper than that and I don't see how ground
>launch from Earth can do it.
>And just how "reusable" is this giant rocket going to be? Are you going to
>carry a heavy heat shield all the way up to geosynchronous orbit and then
>carry it all the way back down to earth again?
I guess they carry 39 tons of water that provides the heat shield
cooling while they are coming back down, but I really don't know.
>Maybe I just get paranoid
>when I hear the word "reusable"; the Space Shuttle was originally
>supposed to be reusable every 2 weeks but that turned into a joke.
It's not impossible. A private rocket flew twice in ten days or so.
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