Re: [GZG] Thrusters

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cisely. There's no doubt one can propose a rationale and mechanics for
thrusters, but I don't see how it can be made the most parsimonious
solution, at least for Terran physiologies. What one might do is come up
with some reason that a race had to settle on multi-axial main drives
rather than flipping the ship with thrusters. It would be an interesting
exercise.

Best,
Ken

--- On Thu, 12/11/08, Robert N Bryett <rbryett@gmail.com> wrote:
From: Robert N Bryett <rbryett@gmail.com>
Subject: Re: [GZG] Thrusters
To: gzg-l@vermouth.csua.berkeley.edu
Date: Thursday, December 11, 2008, 7:00 PM

Obviously your engineering imagination, and taste in PSB, are just as  
legitimate as mine. That's what house-rules are for, but for me:

1. I imagine my interplanetary warships propelled by *at least*  
deuterium-tritium fusion. The "exhaust ducts" would have to be	
massive affairs equipped with superconducting magnets, cryogenic  
cooling and other systems to control the plasma-stream. Essentially,  
apart from the shared "reaction chamber", you'd still be building
one  
engine with Tn thrust plus five with T(n/2) thrust.

2. Man-made fusion for space-ship propulsion remains a fantasy, and I  
am not a nuclear engineer, so I have no idea how feasible it would be  
to open "ports" in six different directions from your main tokamak or
 
whatever.

3. The structure of the ship would have to be stressed to take heavy  
accelerations from six directions instead of just one. The designers  
would have to allow for six major exhaust streams when positioning  
crucial external systems like heat-radiators. Putting a nuclear  
reactor in the middle of the ship, as opposed to one end, would  
probably imply a greater mass of radiation shielding to protect the  
crew (obviously) and ship's structure (from neutron embrittlement).

It seems to me that however you slice it, there'd always be a serious  
trade-off in engine and structural mass to give a ship the ability to  
accelerate in any direction implied by the thruster-push rules. A a  
ship that was designed around a single thrust axis would be simpler,  
and put less mass into engines and basic structure. The single-axis  
design should either have a higher acceleration for any main-engine  
thrust, or be able to put the extra mass into armour, weapons etc.,  
or some combination of the two.

Best regards, Robert Bryett