Re: starship-design: FTL travel

[KellySt@aol.com]

In a message dated 4/17/00 2:40:49 AM, bfranchuk@jetnet.ab.ca writes:

>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.

Oh givern the curent $10,000 a pound launch costs its pretty trivial to get 
90% cost reductions even with only the current launch rates.  99% reductins 
with reasonable rate increase is pretty doable.  Assuming you can get the 
customers and reasonably intrest rates.


>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

I'll have to check it out.


>Fuel costs on the shuttle is about $90/kg, so where does the remaining
>$19910 goes?

It takes 4,000 technicians about 3 months of heavy work to prep a shuttle for 
launch.  Labor and support costs about $200 million per flight.  Drop tank 
costs about $60 million.  A bit more to integrate the cargo.  And assuming 
you don't need to much replacement parts - your up to $300 million before you 
do the launch and pay the mission and launch control peoples payrolls.

$300,000,000  divided amoung 40,000 pounds of cargo is $7500 per pound 
already.  Add in other expenses, or need to take longer to prep the shuttle 
for some reason, and you get up to or above$10 K per pound.


>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.

Can't follow this?

>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.

Hate to tell you but in space you can lift and move tons by hand, and its 
very expensive and dangerous to break down large thinks into many small parts 
for on site assembly.

Kelly