Digest Number 251

>
> >Also, nuclear rockets require a lot of reaction mass,
> what will you use
> and from whence will you obtain/transport it ?<
>
> A lot of reaction mass? In comparison to what? It

In comparison to several things:

1) as a percentage of the total system weight

2) compared with other systems:
a) less than chemical, but that does not mean it can be ignored. It is substantial.

b) compared to electric propulsion, hall thrusters.

You deflected the question so I repeat it..

From whence will you get the reaction mass ?

> would require less reaction mass than any chemical

Yes, I know that.

Answer the question please.

> rocket. An NTR would heat the gas up to the plasma
> state, which would give a higher ISP than any chemical
> reaction.
>

Yes, I know that.

Answer the question please.

> >around $ 100 billion trying to do that over the past
> 50 years, and have
> yet to get close to mastering it.<
>
> Well we are getting closer all the time and He-3 is

No, we have been 15 years away for the last 40 years.

We are not getting any closer to controlled fusion of any kind.

> too rare on earth to try fusion with it. Hopefully we

Nonsense. There is plenty of He3 available for research. He3 fusion requires about a hundred times more ignition energy than Deuterium-Tritium fusion,
which makes it very difficult to initiate.

We do not even have De-Tr fusion yet, let alone He3.

> could build fusion reactors on the moon. In the near
> future I have no problem with building fission
> generating plants on the moon. They could provide us
> with energy and fuel.
>

Nonsense. De-Tr fusion will not happen any time soon.
He3 fusion will not occur in our lifetime, I estimate that it is 100 years away.

Forget about it for now.

>
> I agree, but the activist element won't let you
> launch.<
>
> In that case Hope it's the Russians that do it because
> you can be sure someone will. Just think what it would
> do for the Russian economy to have the only affordable
> launch vehicle. I would expect this to be reusable
> like the shuttle.
>

Hmm, they could get economic sanctions imposed on them. That would be devastating to their economy.

They already have the cheapest launch vehicles, not much
incentive to make them even cheaper especially if there
are serious adverse political consequences.

> >The tally of space nuclear accidents/failures is
> presently six from
> Russia and three from USA.<
>
> And even with all these accidents there has been no
> catastrophic loss of life or any of the terrible
> things predicted by the activist element.
>

Nonsense.

1) Cancer rates amongst non-smokers. To a person having cancer, it is catastrophic.

2) The Cosmos-954 sprayed several hundred pounds of Uranium on an uninhabited area. We were extremely lucky that it did not land 2,000 miles further to the south. There would have been loss of life.

Your philosophy is the same as the folks who authorized the Challenger launch decision.

Their logic went like this....even though we know that the technology is extremely dangerous, we never had a problem in the past, that means we never will, even though we are flying outside of the known safety limits.

Hmm....

How about Chernobyl, there was catastrophic loss of life at every phase of that accident, and people are still dying from it.

A hot NERVA dropping on New York would have a similar effect.

It is no exaggeration that a single microscopic grain
of certain Pu isotopes causes 100% death by cancer.
This was confirmed by the Aldermaston fire in Britain
in the 1960's - several workers inhaled the burning
Pu oxide smoke and later died.

To say that other substances are even more toxic is irrelevant, and does not reasure me at all.

If Dioxin or Sarin were the world's greatest rocket propellants, I really doubt that they would be permitted.

Even today in the CIS there is pressure to get rid of the Proton rocket because it uses highly toxic propellants which are a public hazard, both due to downwind release, and because empty stages return which still have residual propellants. Tiny quantities of
hydrazine are lethal. Believe me, I had the training at KSC - I never handled the stuff, but we were all trained in escape and decontamination procedures in case of a leak.

I am not a tree hugger. But I have worked around these
extremely hazardous materials, toxic, carcinogenic,
corrosive, radioactive, explosive.

I am really not interested in sweeping statements from
armchair scientists who are saying that these things
are safe when they have no experience.

I would like you to sit in a room with a barrel of
isotope or hydrazine, and then tell me with a straight
face that the stuff is safe.

Cheers,

Charles R.