Friday, February 2, 2018

Buttkicker of propulsion system if you can make it work

Originally posted in 2014:


An idea occurred to me last night that the fusion concept that almost works could be used for this propulsion system.  The fusion concept is called muon-catalyzed fusion.

The thermal system Waddington discusses would not be necessary.  Instead, you want to use the alpha particles directly for thrust.  Unfortunately, most of the energy release is from the neutrons, which are not handy, unless you want to breed fission fuel.  The neutrons could be put to good use, though.

Since an energy source would be necessary, and that could be achieved with the SAFE nuclear fission reactor design, which NASA is dusting off the shelf.

However, there is a respectable amount of energy in the alpha particles, and this should be usable for thrust.  Doubtful that this could be used for a SSTO rocket, though.

The main benefit could be larger payload fractions due to the much higher ISP, which reduces the amount of fuel required to run the propulsion system.

If the amount of thrust is sufficient, you could also transit the distance between planets in a much shorter time frame.  If these two benefits are realized, human colonization would be much simplified.

The original 2014 post follows:

Fusion propulsion that is.

An idea occurred to me as I was reading about breakeven in fusion research.  This topic came up maybe a couple years ago when Trent Waddington at QuantumG blog speculated a bit about using fusion propulsion even without breakeven.  He noted that you can get kinetic energy out of it even without breakeven.  The alpha particles would supply the reaction mass and at great velocity since they are traveling at a fraction of the speed of light.

Now at merely 10% of the breakeven point, you'd have enough alpha particles emitted that could give some decent thrust, or so I speculate.

Another thought arose as to the Bremsstrahlung radiation which is such a problem with nuclear fusion as a power source.  The thought is this:  could you use that for propulsion in space?  Like directing the X-rays in the opposite direction of movement like from light pressure from the sun or from lasers.

If you could get enough light pressure and alpha particles from your fusion device, it may be enough to power a spacecraft through the solar system.  Just 1% of the electrical energy input into the system may be enough.  ( honking big speculation alert ).

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