On May 4, 9:55*am, wrote:
Given the desire to use nuclear propulsion for deep space exploration
(i.e. VASIMR, Mars 1986, Mars 1994, etc.), but the danger of
uncontrolled re-entry of radioactive materials ( see Cosmos 954),
maybe all nuclear reactors in LEO should be put there by manned
vehicles, reside on manned platforms, and be manually controllable.
Always having a "man-in-the-loop" provides the same type of additional
safety margin that pilots give to commercial planes.

I noticed that that all the following posting assume
some form of fission nuclear power. I'll suggest
that fusion might be the 'ultimate' power source
for a grand interplanetary drive. Though it might
need a fission reactor for jump start power. The
ideal would be a deuterium/boron fusion reactor though
that needs much work. Then again aneutronic fusion
maybe too 'Star Trekie' to be practical anytime in
the next century or two.

But since fission is a nearer term solution, I'll suggest
LEO parking is better than HEO during the working life of the machine.
At the end of life, a gravity well like the moon or even Venus
might serve as a good dumping ground. If there was a
fleet of ships, landing one one in shallow gravity well
might be ideal as in time when the radioactivity waned
in the distant future the old ships might become a
resource.

For 'space' to fly much beyond Earth orbit, it will take
a better way up, a better way out, a good way down
and up at the goal, and then finding some resource to exploit
out in the great beyond. So what is valuable enough for
the effort? A rare earth element perhaps? Moreover,
processing in such a situation would serve to keep off-world
toxic chemical byproduct wastes.

Trig