In a series of upcoming technology demonstration missions, NASA is hoping to prove that giant solar sails are a practical way to explore the cosmos, even though warp drive engines and rocket powered spacecraft make for better movie fodder.
Starting in 2015, NASA will be launching a series of three experiment driven missions, including one that will confirm the feasibility of using solar sails as a viable means of cheap propulsion. The giant 125x125 foot sail is seven times as large as those previously flown in space, but will one day need to be considerably larger to shuttle astronauts around. But this scaled-down version will at least let NASA test how accurately a sail-driven craft can be navigated, including attitude control using vanes on the tips of its cross beams.
Since NASA's budget has been recently neutered, the agency is focusing their efforts on investing in disruptive technologies that have the potential for a high payoff in future missions. And since solar sails rely on energy collected from photons or radiation already bouncing around in space, it's potentially a completely free source of propulsion, making space travel a far cheaper endeavor down the line. [NASA via PhysOrg]