Re: starship-design: FTL travel

[Ben Franchuk <bfranchuk@jetnet.ab.ca>]

KellySt@aol.com wrote:
 
> I realize.  the segments aremore effocent, but that doesn't mean cheaper or
> more relyable.  Energy or fuel costs to orbit are  trivial, its only the
> operating costs and relyability that are significant.  This system is more
> complex, and therefore likly to be less relyable or cheap to operate.
>

I don't know, as I have not built it, nor have the skill to build it
or a regular SSTO craft, to find out. Unless you have a craft that
is about the size of small aircraft that runs say 3 times a day 7 days
a week, what ever design SSTO or TSTO, payload prices will not drop.
 
This is a neat paper on really cheap space access, and gives some
facts on projected launch costs. With a projected cost of about $60/kg
for basic space access costs (fuel,operating costs),the price jumps to
$600/kg for insurance, launch and profit margin for 4 fights a
week.(300kg payload). 

http://www.spacefuture.com/archive/getting_to_low_earth_orbit.shtml

Fuel costs on the shuttle is about $90/kg, so where does the remaining
$19910 goes?Even greater losses are with the larger designs. While this
does prove your point, it is something I think there is a large room for
improvement.
 
Guessing that CH4/O2 costs about the same as O2 / kerosene ( $35/kg )
we need to pick a realistic figure for costs. Say $150/kg... and a
payload
of 300kg with a unmanned craft. Assuming a 40:1 ratio that is 12 ton
craft
regardless of being SSTO or TSTO. That is too small to deliver nuclear
war heads for the military, put man into space for NASA, or deliver
stuff
for Communications,but is the right size to build things in space,
because
it is the size ordinary people can still grasp and use.


> 
> Kelly

-- 
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 We borrow it from our children."
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