Funny he didn't mention beaming the energy from the ground. At the time of writing (2012) NASA was experimenting with microwave transmission, but it seems they

Funny he didn't mention beaming the energy from the ground. At the time of writing (2012) NASA was experimenting with microwave transmission, but it seems they ran out of fund before succeeding... https://en.wikipedia.org/wiki/Beam-powered_propulsion https://en.wikipedia.org/wiki/Beam-powered_propulsion