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```From: Dani Eder <ederd@worldnet.att.net>
Newsgroups: sci.space.tech
Subject: Re: how to launch?
Date: Wed, 5 Nov 1997 22:03:23 GMT

Benjamin P. Carter wrote:

>  and how
> much will it cost in the future?  (Does someone have
> the figures handy?)

A lower bound would be the cost of the raw energy to get to orbit.  You
need about 30 MJ/kg, or 4 kWh/lb.  That's about \$0.32 on my electric bill
per pound.

A reasonable goal would be 4x fuel cost (about what passenger airplanes
fly for).  Given rockets that eat about 20 lb of fuel per pound of
payload to orbit, and a cost for cheap hydrocarbon fuel and oxygen on the
order of \$0.15 per pound, that would be \$12/lb.  If we allow \$3/lb
payload per launch for fuel, and \$3/lb for our vehicle purchase, and \$6
for everything else, and we assume the vehicle has a hardware weight of 2
lb per lb of payload, we can use up \$1.50 of flight hardware per pound of
payload per launch.  Airplanes produced in the hundreds cost about \$500
per pound to build.  Reuseable rockets produced in the low tens of units
should run about \$1000/lb to build.  Therefore, they should have a design
life of 667 flights (round up to 1000).  Given a useful life of 10-20
years, they should fly roughly once a week each.  With a fleet of 16
vehicles, that gives you about 2 launches a day, and 2 units in the shop.

So...

When we get launch rates of 700 a year (rather than about 7 per year for
a current launch system), we might expect costs to run about \$12/lb, give
or take a fairly large factor for the crudeness of this estimate.

Dani Eder
```

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