Sailing To The Stars

NASA is working to perfect solar sail technology, which would allow ships to move throughout the Solar System and beyond without the use of rockets.

The basic concept is simple, similar to moving across water by letting the wind fill a sail to push the boat along.  There is a solar wind of energetic particles constantly streaming away from the Sun.  A large enough sail could capture enough of that energy to push a spacecraft along.  It would be slow going at first, but the speed would build steadily, perhaps over years, until it reached extreme levels.

Nor is the Solar System the limit.  Within twenty years, NASA expects to have the technology to send a small unmanned probe on an interstellar mission.  That sail wouldn't ride on the solar wind, however-- at least not all the way.  NASA would build a huge, powerful energy beam emitter.  That emitter would stay nearby, but the energy beam it shot out, perhaps a laser, would be focused on the sail of the probe, pushing it to its target star.