Subject:
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Technical nits (Was: Jormungand Carrier Strike Craft)
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Newsgroups:
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lugnet.space
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Date:
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Tue, 19 Oct 2004 04:44:19 GMT
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Viewed:
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1085 times
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OK, as long as we’re picking nits... :-)
In lugnet.space, Jordan D. Greer wrote:
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Without an atmosphere, conventional kinetic damage
(including heat) will not propagate nearly as well
as it would in the presence of air.
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Actually, heat (a form of radiation, *not* kinetic energy) will propagate
*better* in space than in an atmosphere. But for a bomb outside the atmosphere,
a higher percentage of the yield will go into direct kinetic energy of the bomb
parts (called, in this case, gas/plasma expansion), and not into secondary forms
of energy like radiant energy.
Just an FYI, these (first generation) were generally a cylinder of aligned
tungstun wires. The gamma radiation from a nuclear detonation would pump the
tungsten electrons up to hgih enough energies that you’d get X-ray emission,
directed primarily along the axis of the wires. BTW, I was never clear as to if
this was a “laser” (as in stimulated emission) or just a lot of X-ray emission
in a short time from alinear source - there would be a *big* difference in the
percentage of the output directed at the target.
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The energies, velocities, and distances involved in anything
relating to deep space are such that not even nuclear weapons
provide the kind of energy density that one would truly
desire for space combat.
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I’d agree, but I think you’re underestimating it as well. Google for the term
“R-bombing” and see what turns up. It becomes a question of what accelerations
and speeds you have in your fictional universe, but quite possibly kinetic kill
projectiles with no warheads at all make more (economic) sense. If you are
positing ships that can get to anything near lightspeed, forget about nuclear
weapons, they’re pointless. The best bombs convert something like a few percent
of their rest mass into energy... but a raisin hitting at 0.8 c delivers 100% of
it’s rest mass energy. Ouch.
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and spaceships wouldn’t be painted since paint weighs
and costs money (NASA skipped painting the main rockets
for the spaceshuttles recently to save a lot of bucks
per launch).
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Yes, they’d still be painted, for the same reason the orbiter (space shuttle)
still is - thermal control. There’s a *reason* the bulk of the orbiter is white
(to reflect sunlight and thus prevent heating - heat rejection is a bear in a
vacuum), and a *reason* the tiles & RCC surfaces are black (makes them much more
efficient heat radiators). NASA rapidly stopped painting the ET (external tank)
not due to the cost of the paint (trivial, on those cost scales) but due to the
weight of the paint (not trivial, in terms of the final mass lofted to orbit).
To my knowledge, they have never flown with unpainted rockets (the SRB’s), just
the ET.
--
Brian Davis
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Message is in Reply To:
 | | Re: Jormungand Carrier Strike Craft
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| (...) Meh, I'm the same way. I have a lot of projects I'd like to get to, but I never start on most of them. (...) You misunderstood me, I was sort of calling my own comments a nitpick since this argument is rather pointless given the conjectural (...) (20 years ago, 13-Oct-04, to lugnet.space, FTX)
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