Astrophysicists and engineers at the Marshall Space Flight Center in Huntsville, Ala., and the Ames Research Center in Moffett Field, Calif., have designed and built NanoSail-D, a “solar sail" that will test NASA’s ability to deploy a massive but fragile spacecraft from an extremely compact structure. Much like the wind pushing a sailboat through water, solar sails rely on sunlight to propel vehicles through space. The sail captures constantly streaming solar particles, called photons, with giant sails built from a lightweight material. Over time, the buildup of these particles provides enough thrust for a small spacecraft to travel in space.
Many scientists believe that solar sails have enormous potential. Because they take advantage of sunlight, they don’t require the chemical fuel that spacecraft currently rely on for propulsion. Less fuel translates into lower launch weight, lower costs and fewer logistical challenges. Solar sails accelerate slowly but surely, capable of eventually reaching tremendous speeds. In fact, most scientists consider solar sailing the only reasonable way to make interstellar travel a reality.