"There's just a tremendously exciting prospect called solar sailing. [It] travels on the radiation and particles that come out of the sun, the wind from the sun. Because it has a constant acceleration, it can get you around the inner part of the solar system a lot faster...than the usual sorts of rocket propulsion."
That's our late science ambassador Carl Sagan on a 1976 broadcast of the Tonight Show with Johnny Carson. During the brief interview, Sagan fiddles with what looks like a small square of tin foil, a model that he believed was the future of space travel. It's been nearly 30 years since Sagan's solar sail vision, and now his spacecraft, called LightSail, is finally getting a test flight.
The sail is the creation of The Planetary Society, a non-government organisation co-founded by Sagan in 1980. As far as firsts go, LightSail scores the bronze. Japan and the US have already successfully tested solar sail technology. Though LightSail has hit some snags along the way toward its first flight, the craft's real importance relies on its makers. Much how SpaceX defined rocket development for the private sector, so too could The Planetary Society make solar sailing actually affordable and sensible to use. The project costs only $US4.5 million and requires no fuel because, duh, solar-powered.