Re: <Two bits worth

[Brian Mansur <bmansur@oc.edu>]

 ----------
From: KellySt
To: bmansur
Cc: David; hous0042; jim; rddesign; stevev; T.L.G.vanderLinden; zkulpa
Subject: Re: <Two bits worth
Date: Wednesday, February 28, 1996 11:55PM

>Your Idea of an Ion decelerator is new, and may actually help.  But it 
would
>need a couple mods.

High praise from Kelly.  I'm genuinely honored.  Problem is, how much power 
will it take to make it work?

As the ion decelerator module starts to blast the Asimov with ions, its 
relative speed to the starship will eventually reach several %c.  And the 
distance between the two units will increase making the aiming of the ion 
stream dificult to impossible past a certain point.  Also, to keep the ion 
stream upwards of the relative speed to the Asimov we'll need a lot of 
power.  How much is the multi-trillion dollar question.

In terms of stopping potential to the Asimov, a forward rigged ram scoop 
would feel some drag from the stream, depending on how fast we can make it, 
and the collected ions could then be shot back down the ion drive toward TC 
getting two bites of the cherry so to speak.

>If you wanted it to travel much slower than the main ship.  It would need 
to
>be launched years or decades ahead of the main ship.  Which would make it
>impractical.

Its the same delima with tanker scheme I posted a month ago.  It takes a 
while to get the slow moving beasts into position.  The good news is that 
the idea may actually have a chance of working.

>If you were going to send them out at about the same speed anyway.  You 
might
>as well launch them together, separte them at the start of decel phase, and
>start it up.  The Decelerator would boost like a bat out of hell and slow 
the
>main ship with its wake.  It MAY take less energy that way then just using
>the decelerators power in a on-board deceleration rocket in the main ship,
>but I'ld be surprized if it did.

Read about my Two Bits ain't worth 1E-15 cents.  It talks about the idea of 
turning the Asimov into its own decel track launcher.  The Asimov is 
launched carrying most or all of the fuel and RM it needs to lay a decel 
track behind it while en route to TC.  After an initial slowdown burn, the 
Asimov encounters the faster moving track it laid of the years of cruising 
(assuming the ship was cruising the whole time).  Tim noted that there are 
serious drag problems with this idea and I wonder if the reaction mass ratio 
savings are canceled by power costs to accelerate the decel track mass to 
necessarily high exhaust velocities.

>The big problem with stoping is it takes so much power, that caring the 
fuel
>to generate it would overwhelm the ship.

>Hummm.  There is one way your decelerator idea could really have an edge.
> Since the decelerator wouldn't need enough power to decelerate itself and
>all of its fuel, just the light ship.  It may have a much better power to
>weight ratio!  The ship wouldn't need to decelerate the deceleration fuel. 
 A
>microwave decelerator would be very compatable with kevins Microwave sail
>system.

Read my reply to Tim's reply to my Two Bits Ain't worth . . .

>Of, course it also strands the people at the target star system.  So you'ld
>need to build a secoundary system like Kevins return maser.

Its that old question of how automated can we get a robot construction 
force.
Got to go to class.  Hope all this made sense.