The Japan Aerospace Exploration Agency’s Ikaros solar sail is propelled by the photons that hit its super-reflective panels. The 700-pound spacecraft is en route to Venus’ orbit. The space agency also has preliminary plans to collect solar power from space and beam the energy back down to Earth.

http://latimesblogs.latimes.com/greenspace/2010/07/sunrider-japanese-solar-sail-propelled-by-suns-photons.html