[amsat-bb] NO EJECTION MASS Propulsion

[Mike Lemons]

It doesn't violate any laws of physics if you are expending power from 
photovoltaics to propel your spacecraft.

For example, you could push against the Earth's magnetic field to get a 
satellite into a higher orbit.

This article seems to confirm this model, although they don't know what 
they are pushing against:
http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive

I agree that this is probably nonsense, but maybe it isn't.