Re: starship-design: Inter-planetary craft

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

KellySt@aol.com wrote:

> No.  You need to define the amount of cargo to be launched.  If you want to
> 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 build
> 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 

> 25 watts per isp is nonsence.  ISP would vary wildly with the type of rocket
> and the reacti mass its using.

This a ball park figure for 100% efficient reaction engine from a 
energy stand point. 

> 
> Same reason fighter planes need hours of servicing between flights.  Higher
> 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 some
> time doing sheck out on it.  And every so often its taken to a machanich to
> tear down andrebuild and inspect.

   I don't say there will be no down time, but that is why you have
several
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 could.
 
   I just need to find 74 more people with the same interest.
The bigger platform is cheaper makes no sense to me.

>  Your small platforms would need to wait until after soimeone built the big
> 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.
http://www.friends-partners.org/~mwade/props/loxosene.htm

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.

Ben.
-- 
"We do not inherit our time on this planet from our parents...
 We borrow it from our children."
The Lagging edge of technology:
http://www.jetnet.ab.ca/users/bfranchuk/woodelf/index.html