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My Two Bits Ain't Worth 1E-15 (Take 2)
Okay, I just realized something about my two bits worth. They ain't worth
squat. I ran the numbers for 11GW/ton/s on my portable RPB decelerator idea
and came back to the same problem that Kelly has with his Explorer design.
We need too stinkin much power.
Assuming 11GW/ton/s to accelerate a measly .036 g and using a De + 3He
reaction that yields 3.606E14 Watts/kg and applying that over the time it
takes to accelerate to 1/3c at .036 g the numbers got supremely ugly in
terms of fusion fuel weight.
Back to the drawing board.
Perhaps the launcher idea could still work with the Explorer design. What
we have to do turn the Asimov into its own fuel launcher. Have the ship
rail gun launch most to all of the ship's reaction mass behind it. The
particles will have to be at least fast enough to cover a .25 ly track in
the time it takes to cruise to Tau Ceti.
I wonder: If we could keep the track together over that amount of time and
distance, would it be easier to launch the track from Earth? Would the
stablizing system that Kevin told us about help? I noticed this discussion
but I don't know if it answers my question:
to: Timothy van der Linden
> >Ah, I see your mistake. The angular deflection isn't based on the
> >dimentions of the launcher, but on the accuracy and precision of the
> >correction trim thrusting, and deviation sensors.
> Yes, I was already expecting that something could be the case.
> >You measure the course of the accelerating packet with lasers and use
> >magnetic or electrostatic fields to adjust the direction. (Its easier if
> >do this after it leaves the end of the accelerator.) This way the final
> >presision is not related to the size of the launcher.
> This assumes you can quite accurately steer a packet,
> but a packet is build up of a lot of small particles all
> going their own way (of course mainly forwards). ----
Who says? A fuel packet could be the size of a fright car of that would
help, but I'ld assumed it would be smaller. More like pill to bear can
sized. It would almost impossible to spray a charged fog of particals out
a gun and keep them together. Their mutual repulsion would cause them to
defuse to much. You'ld have to pack them in mini-containers. I supose you
could treat those containers or packets as particals, but I don't think
what your thinking of.
So is the answer yes or no.
As the Asimov begins its deceleration phase, the relatively faster moving
reaction mass track slams back into the ship. We ionize the RM and run it
through the accelerator for thrust just as if it were interstellar medium.
A downside to this idea is the drag caused by hitting the really fast
particles at the end of the deceleration run. Also there are going to be
serious power cost to launch the track.
Kevin's 11.5 ly long power cord is looking better all the time.
Since we'll have to carry so much reaction mass for the launch track, I
suggest we use the E18W we have planned to mag-sail launch the ship. So I
guess we launch the track via the ion accelerator using it as a rail gun if
that is possible.
Someone else had better run the numbers on the drag and power needs. That
is if anyone thinks this has a chance of working. If not, please show me
the error of my ways.