Re: LA-4541-MS
- From: Willie.Mookie@xxxxxxxxx
- Date: Tue, 1 Apr 2008 04:23:42 -0700 (PDT)
On Mar 31, 2:31 pm, BradGuth <bradg...@xxxxxxxxx> wrote:
On Mar 31, 7:49 am, Willie.Moo...@xxxxxxxxx wrote:
On Mar 31, 10:41 am, "Martha Adams" <mh...@xxxxxxxxxxx> wrote:
<Willie.Moo...@xxxxxxxxx> wrote in message
news:f29d0bcd-7493-42c5-a0b7-900720246373@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I was just reading a declassified document this week-end about Nuclear
Pulsed Space Propulsion Systems (LA-4541-MS)
http://www.lepp.cornell.edu/~seb/celestia/orion/
It has some great analysis of the limits of nuclear pulse vehicles.
Namely, figures 4 and 5 which gives mass scaling laws for nuclear
pulse vehicles. Very large payload fractions, very small propulsor/
pulse-unit fraction. Larger vehicles are favored over smaller ones.
<snip>
That's a mighty interesting post: I've been
over to that link's other end and it's a
nice pointer to a possible future. Which I
regret to say, won't come in my time. The
resources to do this now are at hand now; but
Washington seems to prefer wars.
Anyhow, I posted this link into rasff; I should
have included attribution: oops, missed that.
I'll look for a way to catch-up that detail
later.
However. As I was looking at the nice
cylindrical spacecraft in the excellent
images there, I thought, is this really
the best shape for a craft that's out in
space in company of objects moving up to
40 miles/sec or so? One longitudinal hit
from such an object, and that ship is
*gone*.
Would a pancake configuration be better in
that environment? It wouldn't look as
sexy from a male human pov; but you would
not have all the machinery and people in a
neat linear array so one strike could take
it all out.
Titeotwawki -- mha [sci.space.policy
2008 Mar 31]
A vehicle that is launched through the atmosphere is better long and
pencil like. Population statistics versus size and vehicle swept
volume determine the likelihood of a hit - any hit is likely a
killer. A vehicle that makes it mars in 40 days has 1/10th the
likelihood of being hit by meteors as the same vehicle that takes 400
days to get to mars.
But a 10 fold increase in travel velocity makes those smaller bits of
debris that could have been deflected or safely absorbed, instead into
becoming lethal encounters worth nearly 100 times as much greater
impact energy. Therefore, going fast requires a "pencil like"
composite shell of perhaps layers of solid thorium, or of whatever's
tougher.
. - Brad Guth- Hide quoted text -
- Show quoted text -
You wrongly believe that vehicle velocity changes population
statistics. That is, you assume that the material you hit forms a
statoinary field through which the vehicle passes like water or air
for a earth bound ship. This is not the case in the space environment
and treated in the literature. You really ought to read a book on the
subject before posting, rather than posting based on your gut feel.
.
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