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Re: Engineering Newsletter

>> Heat load on the asimov:

>> Heat generation will come from two sources.
>> 1) (and the largest) conversion of microwaves to 
>> electricity.  This takes place with between 85 - 90 
>> percent efficiency, and for our purposes, 15% 
>> heat load (from 1E18 Watts) is still a lot.

>> _BUT_
>> the conversion would take place on the antenna itself.  
>> diodes wired directly onto the metal mesh would do the
>>  power converting and the mesh  (of special radiator fins 
>> if need be) could radiate the heat.  we have thousands and 
>> thousands of square meters of antenna, it would serve as 
>> an exceptional radiator.  ----

I'll buy this part.  With the hundreds to thousands of square kilometers of
mesh you've been taling about you have a lot of radiator space.  Asuming you
can radiate the energy away fast enough to keep everything down to operating
temperature.  If you want supper conductors this could be dicy.  They like
cold temps and radiators like it very hot.

>> 2) heat will be generated in the coils for the linear 
>> accelerator core.  This can be minimized by using 
>> superconducting electromagnets, but there will always be 
>> inefficiencies.  Assuming that we can get 99% efficiency 
>> out of superconductors, (not unreasonable)  that means we 
>> will have to  deal with 1 E16 watts of thermal energy.
>> _BUT_
>> This will be spread out over the length of the entire core.  
>> also, we are going to have to raise the temp of the 
>> reaction mass from near Zero (kelvin) in the case of
>> Hydrogen, to something approaching room temp 
>> -- (the reaction mass would then also serve to cool the 
>> superconductors)

>> This heat, rather than the anntenna heat would probably be 
>> best suited to  heating the living quarters.

Kevin, the heat your talking about is enough to provide for all the
electricity for a few thousand cities the size of Chicago!  Thats the kind of
power that keeps all those cities outside air temp a few degrees above
country temps.  You can't just brush that off by saying the engine will be a
few klicks long and were can pump a lot of heat into the reaction mass.
 (Frankly I doubt the reaction mass can absorb that kind of heat load.)  This
is a lot of power, and we need to know what were going to do with it or the
ship will cook itself alive.