Subject:
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Re: Hypothetical design question
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Newsgroups:
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lugnet.space
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Date:
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Tue, 24 Jun 2003 03:48:04 GMT
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Viewed:
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686 times
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In lugnet.space, Tom Bozzo wrote:
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Density does indeed matter -- and there I was off by a good bit (a NASA
Goddard page gives 1 atom per cc as the density of the interstellar medium),
though the drag/energy dissipation problem still seems manageable until you
get to very high relativistic speeds. For instance, it’s only a few hundred
kW per square meter of frontal area at 0.95c and the 1 atom/cc density --
comparable to the peak output of a fast car’s engine. Nothing, really, if
you can accelerate a spaceship to 0.95c in the first place.
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Yeah, one would hope that if we ever achieve the capability of moving that fast,
we’d also have the capability of dealing with associated problems. And if it’s
comparable to a sports car’s engine, I’d think heat buildup would be a bit of a
problem. It’s not like you can run an air-cooled engine in space, and large,
delicate heat dissipators would probably snap off during acceleration.
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Back on the topic of building, I think the nature of the medium would make it
a challenge to to build, with real bricks, an interesting-looking and
stucturally sound model of one of those needle-shaped relativistic starships,
the underlying science or lack thereof notwithstanding. A much-extended
version of Bruce Lowell’s “Starflux” comes to mind for starters.
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Indeed. You’d probably have to go for a really long MOC to get the profile
right, and then you’d have a long, skinny, fragile fuselage. Probably the only
way to pull it off would be to use some transparent struts to support it at
regular intervals. I’d think one or maybe two per large baseplate width would
be adequate. Of course, here’s an interesting design challenge to go with it.
If you make a long skinny ship that’s designed to be able to survive particulate
impact at near-c speeds, how do you stop it when you’ve reached your
destination? It’s not likely to survive being spun around (which is probably
the most commonly accepted idea on how to stop an interstellar ship), and it’s
not like you can have another thruster mounted on the skinny tip.
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Message is in Reply To:
 | | Re: Hypothetical design question
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| (...) You're right, though I read Jonathan's point as being that I didn't account for relativistic effects in the energy calculation, which is true. If I have the math right, the crossover point where the relativistic energy exceeds the rest mass (...) (21 years ago, 24-Jun-03, to lugnet.space, FTX)
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