Subject:
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Re: MOC: Thousand Astronomical Unit Probe (NEF)
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Newsgroups:
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lugnet.space, lugnet.build
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Date:
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Wed, 8 Aug 2001 23:29:12 GMT
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Viewed:
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37 times
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In lugnet.space, Kyle D. Jackson writes:
> In lugnet.space, Lindsay Frederick Braun writes:
> >
> > Hi everyone,
> >
> > I've been working off and on since Brickfest
> > with my latest project, a "NEF" (Near-Earth-Future,
> > an odd-sounding but standard term) extrasolar survey
> > ship. I'm operating in the relatively unpopular
> > grey zone that a few of us like, the near-future
> > "technically possible today" zone.
>
> Cool, somebody's building something real! <G>
>
> I must confess, I really enjoyed the page, but I didn't
> look at the MOC so much as reading all the cool text. I
> eventually ended up hopping to some other sites to learn
> about the Heliosphere :]
>
>
> > TAU (Thousand Astronomical Unit) was a real mission
> > proposed in the 1960s, and a vehicle even got into
> > the early stages of design. I've ressurected it
> > for a universe of about seventy years hence, after
> > humanity has just discovered a feasible stardrive
> > with only one catch--you've got to get to the helio-
> > pause to use it, because stellar gravity wells
> > distort the effect in a rather unpleasant manner.
>
> Okay I have 2 questions, probably related. The first is
> why does this drive only work well beyond the heliopause?
The "drive that works beyond [sic] the heliopause" is
the actual stardrive. That's a different technology, a
fictional one. The idea is that you have to use the
pulse drives to get it to the point where the gravitation
of the Sun is sufficiently weak before you can fold space
to your destination. Gravity wells work against the
effect, so the closer you are to the source of that well,
the more energy is required to execute a fold maneuver.
The actual "Daedalus" project, however, envisioned using
the pulse drive for the whole trip. I'm only talking about
using it for *sublight* operations within the system. I
think that's the drive you're thinking about.
> The other is how does the drive actually work? I've heard
> the concept before but never really dissected it until now.
A good explanation of the principle is found in several
sites dedicated to the Orion launch vehicle, which was
NASA's planned nuclear pulse rocket.
Here's a page with the quick and dirty info:
http://www.upei.ca/~physics/p261/projects/spaceprop/NUKE.HTM
Basically, the ship rides the shockwave--which does not
require much of a medium to propagate, unlike sound. It's
more like a wave. My TAU is supposed to use that wave only
for propulsion, not for other power--there's a secondary
reactor for that, further forward.
> What is the mechanism that tranfers energy from the explosion
> to the ship to move it? I'm assuming that the nuclear
> eplosion produces tons of energy but very little in the
> way of matter (gases, etc). With no matter to transfer
> momentum to the ship, what makes it move? Granted the
> explosion will radiate energy through vacuum to the ship
> (e.g., heat), but that would just make it hotter, not make
> it move. What am I missing here?
It's primarily the pulse (EMP, mostly), but it does require
mass:
http://www-spof.gsfc.nasa.gov/stargaze/Snucfly.htm
But the idea was that the pellet undergoing fusion would provide
the mass at such a high speed that energy would be sufficient.
best
LFB
best
LFB
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Message has 1 Reply:
 | | Re: MOC: Thousand Astronomical Unit Probe (NEF)
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| (...) momentum from the explosion to the ship are gases released from vapourizing the casing of the bomb. I guess I can envision a dense enough wave of such gases being produced to transfer momentum to the collector shield and cause thrust on the (...) (23 years ago, 10-Aug-01, to lugnet.space, lugnet.build)
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Message is in Reply To:
| | Re: MOC: Thousand Astronomical Unit Probe (NEF)
|
| (...) Cool, somebody's building something real! <G> I must confess, I really enjoyed the page, but I didn't look at the MOC so much as reading all the cool text. I eventually ended up hopping to some other sites to learn about the Heliosphere :] (...) (23 years ago, 8-Aug-01, to lugnet.space, lugnet.build)
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