starship-design: What is safest?

[TLG.van.der.Linden@tip.nl (Timothy van der Linden)]

>>Before making the discussion unnecessary long: What kind of repairs do you
>>consider to be mayor and to be necessary in 60 years but not within 30?
>
>More structural repair due to fatigue and corosion.  Power cables and
>distrabution systems, reaction vessels for life support reactions (distilation
>of water, air processing and synthasis, etc), plumbing, ductwork, pumps,
>bearings for the hab centrafuge, etc.  Also electronics get increasingly
>erratic at those ages.

But is designing for a doubling of lifetime impossible in the next few decades?
In what way can current Eartly goods be compared to the equipment we need.
Are there any goods of which lifetime doesn't depend on costeffectiveness?
(Ie. Are there manufacturers for whom it pays to design a 3 times more
expensive product but with a 2 times longer lifetime?)

>Food also becomes an issue.

For some reason 40 years of freezedried food doesn't soon very appealing. I
guess that potato chips may be a useful food source after all. ;)

>Paradoxicly the engines to boost back are fairly safe.  They don't need
>complex micro systems, and being unpowered arn't under load or much thermal
>stress.  Due to the large scale these engines and reactors must be.  Minor
>corosion on metal to metal contact points isn't critical.  To be stable the
>engines would have to stick to simple stable alloys (copper vers super
>conductors etc.), which would also increase stability.  

While an engine may be more robust than "micro systems", it also has to cope
with orders of magnitude more stresses. Won't these stresses speed up metal
fatigue beyond proportion?

>So a 2 way flight puts most stress on the drive systems, which generally have
>only been used for a few months, but least on te general suport systems for
>the ship which have alread  been in use for deacades.

It does however need to gather bulk amounts of fuel in the target system.
(Assuming you don't need other infrastructure like beaming stations.)

Timothy