[AR] Re: DARPA responsive launch challenge
- From: Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sun, 22 Apr 2018 21:04:28 -0700
On 4/22/2018 8:32 PM, Henry Spencer wrote:
On Sun, 22 Apr 2018, Henry Vanderbilt wrote:
...stabilized atomic hydrogen (just how it's stabilized is, of
course, never explained)...
Mind, given the stabilization is SFnal handwaving, you could assume
it's *stable*. IE, not prone to detonating if looked at cross-eyed,
and comes out of the reactor still monatomic.
I fear I don't believe it, at least not unless we do some cross-genre
borrowing and get Harry Potter involved. :-) No conceivable molecular
bonding is going to stay 100% intact under NTR conditions, and with this
stuff, 99% is not good enough. I think it would take new physics, not
just new chemistry, and the new physics would probably be good for
enough other things that atomic hydrogen would take a back seat quickly.
(Without that, I don't say it's definitely impossible, but that's the
way I'd bet.)
Oh, ultra-stable single-H would take nucleonic engineering (is that a
thing? perhaps not quite yet...) not mere chemistry. And as you say, at
that point we could probably come up with far better propulsion methods
than heating single-H in a fission reactor.
At least part of my point was that someone writing SF in the fifties
didn't know a fraction of what we do about what will and won't work - we
have both sixty years accumulation of practical knowledge *and* far
better access to it than a fifties SF author. Heinlein may well have
assumed it stayed stable going out the exhaust in running his numbers.
(Hey, at least he ran some numbers - more than most did, and it showed
in a lot of those books.)
Metallic hydrogen (or Bob Forward's metastable helium), if it's stable
at reasonable pressures once made, does seem more appealing.
For a very narrow definition of "appealing", mind. Not too far behind
antimatter for being able to accomplish major demolition with miniscule
amounts of the stuff.
Henry
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