This is absolutely amazing!! Pardon my ignorance, but how does this compare to ion thrust? Unless that's still theoretical, that is -- this seems like an even more elegant solution that ion thrusters.
Ion propulsion is not purely theoretical - the Dawn mission currently entering orbit around Ceres got there under ion propulsion, having previously rendezvoused with Vesta.
Wow! Thanks for the info, looks like I've got some reading to do.
Ion thrust of course has the advantage that it keeps working if you get farther away from the sun. But for the inner solar system, light sails are very promising.