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Re: starship-design: Inter-planetary craft

In a message dated 4/18/00 10:36:29 PM, bfranchuk@jetnet.ab.ca writes:

>KellySt@aol.com wrote:
>> No.  You need to define the amount of cargo to be launched.  If you want
>> launch a hand full of components like the ISS space station, you probably
>> could support a launcher system much below $2000 a Kilo.  You want to
>> and operat a space hotel like in 2001.  You could probably get well below
>> $100 a kilo.
>Daily for 500 kg craft:
>5 people ( manned craft )-- 500 kg  1 launch
>1,500 kg ( unmanned ) cargo/bulk fuel. 3 launches 

5 people weigh more then 500 kg.  Besides thats to small, you couldn't carry 
anything interesting up.  Unless of course you just want do do a tourist hop 
and come back down.

>> Same reason fighter planes need hours of servicing between flights. 
>> performance, higher stress systems pushed closer to limits.  More complex
>> systems.  It'll be a while before we can make something with margins
>so thick
>> you can take such chances.
>> Oh, but you NEVER just fuel and fly a small plane.  You always spend
>> time doing sheck out on it.  And every so often its taken to a machanich
>> tear down andrebuild and inspect.
>   I don't say there will be no down time, but that is why you have
>aircraft ready for flight.
>> >I want to build a small complex  with say 75 people in a habitat, not
>> >the empire state building.(25 rooms).
>> You couldn't possibly afford it, or support it.  A bigger platform you
>   I just need to find 74 more people with the same interest.
>The bigger platform is cheaper makes no sense to me.

The bigger platform can use more eficent launcher systems, and has far more 
space to market.  a 75 person platform couldn't keep a effoicent fleet 
operating.  Unless it was a hotel that cycled folks down after a week or two?

>>  Your small platforms would need to wait until after soimeone built the
>> ones.  Also you need a platform big enough to spin for full gravity.
>This would about 2x the size of  apartment building I liven,
>room for gardens and pets and play areas.
>> >Guessing that CH4/O2 costs about the same as O2 / kerosene ( $35/kg
>> >we need to pick a realistic figure for costs.
>> Wait a minutte.  Liquid O2 costs about $0.05 a pound and I think kerosines
>> about
>> $0.25 a pound?  Where do you get $35 a kilo?
>That is fuel and base costs to place 1 kg in orbit.
>With about a 40:1 ratio for just fuel $11.20
>O2 is $.8 and $.20 for kerosene 1980 for 1 kg.
>I have no idea the price of CH4 so I am guessing here it is the same.
>liquid hydrogen is $3.80 for 1980 prices.

Liquid hydrogen was about $1 a pound, CH4 is a lot cheaper since it has more 
comercial use.