RE: Re: starship-design: Does a one-way mission need mining?

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

On Monday, December 29, 1997 10:28 AM, Timothy van der Linden 
[SMTP:TLG.van.der.Linden@tip.nl] wrote:
>
> True, so we should try to avoid these substances. This may mean shorter
> durability and other undesired characteristics. Whether we should really
> avoid them, will depend on how undesired the properties are and how heavy
> the are to take with us, or how difficult they are to mine in space.
>
Unfortunately, this isn't always possible. What Kelly means is that some 
everyday substances have very strong chemical bonds which makes them 
difficult to disassociate into their constituent elements. It isn't 
impossible, merely difficult and expensive. Now from a starship's point of 
view, where EVERYTHING is precious, this may not matter. We have energy to 
burn and it is MUCH more expensive to send a replacement from Earth so 
Kelly's point is only half valid. The thrust of his argument however was 
simply that it would be cheaper (mass wise and energy wise) to simply mine 
new raw ore at the destination system.

> Well, I don't know that much about lifesupport systems, but I wonder:
> When
> air can be kept usable for a 5 to 10 year trip trough space, is it that
> much
> harder to keep it usable for a much longer period?

Recycling isn't the problem, air loss is. We can't seal a ship sufficiently 
tight to prevent leakage from becoming a problem after a few years. I'm 
afraid we are rather poor engineers at the moment...

Lee