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Re: LIT TC Project (fwd)

Hi Lee,
In responce to the message you sent to Kevin.

At 11:51 AM 2/12/96, Kevin C Houston wrote:
>recieved and fwd. please add this person to your LIT mail list.  he seems
>---------- Forwarded message ----------
>Date: Sun, 11 Feb 1996 17:57:41 -0600
>From: L. Parker <lparker@destin.gulfnet.com>
>To: Tex Houston <hous0042@maroon.tc.umn.edu>
>Subject: LIT TC Project
>Hi Kevin,
>I am a little new here and have been reading through older postings as fast
>as I can. So if I duplicate an issue or repeat a question that has already
>been answered please excuse me. Is there an updated version of Kelly Starks'
>proposed configuration for Asimov? It seems some major profile changes have
>been made since he posted it in '94.

I've been meaning to, but life got in the way.  That old draft is very
drafty, and needs some correction and updating.  You should note though
that it is not 'the' ship design, it was my cut at a possible design.  My
design used Fusion powered drive systems feed from carried fuel and fuel
launched ahead of it by a fixed fuel launcher.  Some of the ideas listed in
their didn't pan out, and the ship itself is not capable of geting to Tau
Ceti in a usable periode of time.  But a lot of the general systems designs
and equipment (hab-deck design, types of exploration ships and equipment,
etc..) seem to be the basic concept everyone has tacitly accepted.  Thou
the others are leaning more toward some sort of microwave powered
relativistic drive.  Unfortunatly we can't think of one thats likely to
work (stoping is a big problem!).

In the next draft I hope to upgrade the numbers included in there, add
illistrations, and write up associated summary documents for the groups
progress to date.  (Did you see the draft summary document I sent around?)

>Have you compared simple solar pumped mechanical lasers to the microwave
>generators? They would not transmit power as effectively, but it seems to me
>that they could be massed produced in HUGE numbers to provide more than
>enough power and remove the need for quite so much magnetic shielding.

How would microwaves vs lasers effect shielding requirements?

>BTW, I am not sure depending on shielding generated by an external wire mesh
>dish is such a good idea. As Kelly pointed out in his early design proposal,
>we don't really know what the composition of interstellar space is. Suppose
>that just occasionally we run into something bigger than the shield can
>deflect, or a pocket of denser media which imparts more kinetic energy to
>the structure than it is capable of abosrbing...might be a good idea to
>combine both shielding ideas (mass/magnetic) as well as any other built in
>redundancy we can come up with.
>Matter of fact, I am not too fond of the idea of the mesh period, too many
>things can/might/will go wrong with it. Sure would be nice if we could focus
>magnetic fields over a long (1000 km) distance. That might even allow us to
>resuscitate the idea of using a RAM scoop.

I'm a little confused.  We were considering making the microwave
sail/reflector out of mesh, but not the shielding.

>Most of the postings I have read seem to assume a period of coasting in all
>configurations, why? It would be far simpler to design for continuous 1 G
>acceleration for the duration of the mission. It might even be a good idea to
>DESIGN for operation at up to 3 or 4 G for extended periods (Emergency
>Contingency Planning).

In general we have problems generating the thrust needed for continuous G;
and since the ship has to drift few the target star system during
exploration, we need artificial G anyway.

>Okay, now for some REALLY strange questions...
>1) Has anyone calculated the mass density of matter impacting the ship at
>.99 c and computed how much and what kinds of primary, secondary, and
>Cherenkov radiation would be generated? CAN we provide that much shielding?
>How about blue shifted free radiation? Wouldn't there be a great deal of
>radiation in the x-ray and gamma ray bands? Can we shield against it? Also
>remember that at relativistic velocities the event horizon contracts for and
>aft, concentrating the radiation exposure there.
>2) What is the particle density in the various speed regimes? Is there a
>minimum speed at which the density would become great enough to initiate an
>EXTERNAL fusion reaction similar to a QED-electric REB plasma rocket (page
>11 of Kelly's paper)? Now wouldn't that be neat? An air breathing spaceship!
>3) Generally, what is the MAXIMUM particle density we could safely use for
>4) Generally, what is the maximum particle density we could safely navigate?
>5) Can we detect increased particle density ahead of our course by any
>means, and at sufficient range to allow us to generate enough delta v to
>avoid it? Twould be a shame to lose the first interstellar mission to a
>cloud of water vapor!
>Well, enough for now, I have lots more questions, many of which, like some
>of these, may not be germane, but what the heck, someone has to ask them! :-}
>Lee Parker
>+                                                                             +
>+  Weave a circle 'round him thrice, and close your eyes with holy dread...   +
>+                                                                             +



Kelly Starks                       Internet: kgstar@most.fw.hac.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.fw.hac.com/external.html)