starship-design: Re: starships

[KellySt@aol.com]

 Good evening,

      I just got around to reading through the design 
 study for the explorer class starships. The references
 are mostly 3 years old
but quite adequate for the study. I did notice that you 
 have Li6 yielding an exhaust Velocity of about 8.33% 
 Cee, When I looked
 into this

Li7 + H1 will yield about 4.81% to 6.818% Cee. You can 
 gather the H in situ and just load the Li&, which is common.
 So to go near 30%C you only need about 500:1 FMR 
 ( down to 81.45 :1 at the highest Vex)

  You might be able to get by with less, but not if you 
 use the same propellant on board for the whole trip. A 
 magsail and solar
induced reaction can act to slow the craft down when 
 entering the new system.

  The life support can also be reduced several ways. 
 But you want to keep the fresh food and the plants to 
 make the air smell
fresh. It just may not re4quire 200 tonnes per person.

  The landers and exploration satellites are best stored 
 as parts and designs and not the finished craft so that 
 they can be reconfigured as needed. Some have to be 
 ready all the time for outside repairs and other 
 emergencies.

Jim
    F
 C'= C
    F'   Cerulean Freight Forwarding Company
          http://www.nvinet.com/~cffc/page2.htm


Hi Jim,
I'm a bit disturbed to hear I might have gotten the exaust velocity wrong.  
I'm out of town on a contract, so I can't review my notes.

The later Fuel/Sail configuration deals with some of your concerns.  With the 
fuel spread out into a microwave sail.  The ship can be accelerated to cruse 
speed without taping its fuel.

Solar sails are pretty useless since you don't spend enough time near a star 
to put it to use.  Mag-sail was debated, but no one knew enough to know how 
to put it to use, or if it could be.

I'm not sure how storing the the support craft as parts helps any?  Since you 
need several craft assembled simaltaniously, your might as well store them as 
assembled craft, not parts.  Most of the parts wouldn't be inter-changable 
anyway.  Its not like a areo-shuttle hull could be adapted to serve as a 
satelight hull?

Anyway, glad you liked the site and were interested enough to write.

Kelly