In article ,
Paul Spielmann wrote:
that i have asked peoeple that i think are credible people that work
in the field of physics (not space engineering though) and accoarding
to what they have said: the energy and heat stress of going to orbit
and back are much more higher than for example what a car experience
and therefore it cuts back what is possible to do with space crafts.

The extent of these problems is much exaggerated, especially by people who
don't have direct knowledge of space engineering.

In some cases, there are real problems but they are artifacts of current
design practices, which can and should be changed. For example, rocket
engines often experience a great deal of thermal stress during startup,
due to very rapid temperature rises. But there is no fundamental reason
why their startup sequences need to be so fast. Limiting warmup to rates
normally found in jet engines is not a big problem, once designers start
caring about reliability and long life rather than absolute maximum
performance.

In other cases, these beliefs are simply misunderstandings, partly based
on authoritative statements from people with vested interests in keeping
spaceflight expensive and difficult. (Of *course* NASA will tell you that
space is terribly hard; it would be immensely embarrassing for them to
admit that they've been wasting your money all these years...)

...I still wonder though how long
life spans sub/orbital rlv vehicles will have though..

It's an open question. The first-generation ones may indeed have somewhat
limited lives. There is much speculation about this, most of which boils
down to religious arguments about basic assumptions. The only way to know
for sure is to try it and see.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |