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Re: starship-design: Re: FTL travel

In a message dated 3/17/00 8:56:45 PM Pacific Standard Time, stevev@efn.org 

> Ben Franchuk writes:
>   > Finding the equation just recently  Power (in watts) = ISP ( impulse )
>   > * 9.8 ( g ) * N ( newtons of thrust ) / 2. Any propulsion system
>   > would require MAMMOTH amounts of power. Heat dissipation is the limiting
>   > factor here.
>  As has been pointed out before, fuel is the real limiting factor.
>  Fusion power is barely capable of driving a ship to relativistic speeds
>  with large, but not completely untenable, fuel-to-payload ratios.
>  Talking about building an interstellar spacecraft that uses fission
>  power is just plain ludicrous.

Present fusion reactors (surprise) like breeder reactors that by fusion 
reactions produce plutonium239 and Americium241 from U235 are common. Almost 
all atomic reactions contain fusion and fission products to a lesser or 
greater degree. Attempts at containing fusion power at high enough level to 
be useful have failed for the plasma escapes all known 3 dimensional 
confinement. I noticed that the plasma leak from attempts could be enlarged, 
focused and contained becoming a fusion reaction contained in two dimensions 
without problems. 

In lay terms thing of a fire cracker containing a chemical reaction until the 
three dimensional container (paper wrap bursts) compared to a broken 
firecracker lit that fizzes because it is now a two dimensional container 
like all rocket engines.

This leak effect combined with the China syndrome principle are the physics 
my engine works on. The atomic reaction is successfully contained in two 
dimensions as defined by a rocket engine and differs from the 3 dimensional 
containment of reactors or bombs.

As with known bomb and reactor fusion and fusion reactions, my plasma from 
Americium 241 above critical mass contain mostly fusion compared to fission 
reactions. The liquid propellant (water) exposed to the plasma temperatures 
has mainly fission (hydrogen) with some fusion products. The higher the 
plasma temperature the smaller the fission parts.

> There isn't enough fissible material in
>  the solar system to power a spacecraft at 1 g acceleration for a whole
>  year.

Even were my "fusion drive" very low efficiency aboard my 105 ton craft only 
1/2 ton of americium 241 need to be converted to the energy required to 
accelerate the 100 tons of propellant causing the 5 ton payload to approach 
light speed relativistically to earth observer and with time dilation effects 
greater than light speed wrt to the ship for just such an acceleration. 

Practically the exhaust stream needs detuned splaying the exhaust reducing 
the acceleration to maintain a constant 1 g. this makes 1 ton converted 
necessary for the 50% exhaust efficiency. As with most atomic machines the 
ratio of radioactive metal mass vs the mass converted is not 1:1 but 10 :1 is 
more reasonably expected and 5:1 (20% efficiency) more probable. With my 
design the 5 tons plasma fuel (americium 241) not converted become part of 
the propellant and ejected providing propulsion. This allows the payload to 
be the 5 tons for crew and life support systems and not part of the payload 
side of the general rocket equation:

(Mass times Velocity) of payload = (Mass times Velocity) of exhaust. 

The energy equations used are E=1/2 MV,  and E=MC^2 , P=MV, V=d/t, and V=gT 
and are the determining factors for the velocities my rocket can obtain with 
E=energy. P=momentum, V= velocity, g = 1 gravity (32 ft/sec^2, V=velocity, 
d=distance traveled, T and t= time.

Relativistic equations can be used for observer effects and time dilation at 
calculated velocities. Recall all aboard the craft even appears normal wrt 
the ship crew regardsless of the velocity (Basic posulate of relativity)

The equation Power (in watts) = ISP ( impulse )
 * 9.8 ( g ) * N ( newtons of thrust ) / 2  are not used as they are ISP 
equations for chemical rockets based constants determined on measured power 
ratios of chemical rockets reactions vs velocity.

They have no real world comparison for atomic rockets with the single 
exception of some atomic rockets that expel the propellant instantaneously 
(like most chemical rockets) in a very short period of time compared to 
system time. The ISP measurements database does not even exist for atomic 
rockets beyond poor guesswork of the 1950's. The working equations are the 
ones I gave. The limiting difference in velocities is determined by momentum 
needed to be overcome which approaches infinity with machines using 
instantaneous acceleration. One violates (instantaneous) the laws of momentum 
and the other does not. Common particle accelerators are other examples using 
instantaneous acceleration.