Reply To: Alexander Franklin Mayer's Physics

[dennisp]

No argument there. There’s definitely a business model for rockets, given SpaceX and the asteroid mining company, but for a while it’ll be nothing compared to the energy market.

The one advantage of the space market is that you’re a lot less cost-constrained. Your super-high-performance rocket doesn’t have to be cheaper than burning coal. Helion doesn’t look terribly expensive but I haven’t seen estimates.

I did just find out the exhaust velocity of this fusion rocket, NASA says about 30km/sec: http://www.nasa.gov/directorates/spacetech/niac/2012_phaseII_fellows_slough.html

That’s a lot less than focus fusion, which according to some forum posts around here a couple years ago would be about 3% lightspeed if we just used the ion beam directly. Thrust would be lower since there’s a lot less mass involved.