RE: starship-design: What is safest?

["L. Parker" <lparker@cacaphony.net>]

On Saturday, December 20, 1997 7:19 AM, Timothy van der Linden 
[SMTP:TLG.van.der.Linden@tip.nl] wrote:
> What military system HAS to work? Virtually all systems have backups of
> some
> kind. While the backup is being used, the primary system can be repaired
> or
> replaced with all the outside help that may be needed.
>
I'm afraid the military is a little different than NASA, individual systems 
in the military rarely have backups, which is why such a high expectation 
is made for their reliability. Of course the military compensates by having 
a lot of alternate vehicles or extra equipment so that if the tank or 
aircraft or whatever won't fly, fight, etc., they can simply send a new one 
in its place.

NASA, like interstellar explorers is somewhat limited in this respect. We 
can't send a FLEET of colony ships or explorer ships just to make sure that 
at least one gets there, so we have to take the alternate approach. We have 
to build the redundancy in to the system.

As someone pointed out a few days ago, even though we can't yet engineer 
systems to perfection, we can do much better than we could only fifty years 
ago. It is very likely that we can build systems with 20 or even 30 year 
life expectancies by then. Even so, the limited ability we will have to 
send spares and/or backups will make interstellar travel hazardous. Every 
spare part or raw material carried will cut into the payload fraction of 
the vehicle. We will be forced to make compromises between spare 
parts/extra supplies/mission equipment. There are going to be some 
"Challenger" type disasters where we lose whole ship fulls of colonists. 
Rescue for the crew will be nearly impossible.

Lee

                                                      (o o)
--------------------------------------------------oOO--(_)--OOo---------

He who thro' vast immensity can pierce,
See worlds on worlds compose one universe,
Observe how system into system runs,
What other planets circle other suns,
What varied being peoples every star,
May tell why Heav'n has made us as we are.
					- Alexander Pope