Legendary astronomer Carl Sagan once envisioned a solar sailer, a spaceship that uses sunlight radiation to push itself through the solar system much like a boat relies on the wind. Decades later, his project is about to become a practical reality. The Planetary Society (which was co-founded by Sagan) has scheduled the first test flight for just such a solar vehicle, the LightSail, on May 20th. This initial run will see if the craft can successfully deploy its four Mylar sails. It won't be in a high-enough orbit to harvest the Sun's energy, but the experiment should pave the way for an honest-to-goodness sailing test in April 2016.
This isn't the first sailer, we should add. Japan's IKAROS probe took flight in July 2010, and NASA launched its own example just months later. However, LightSail could be very important for the future of space travel, especially as it shifts toward private companies. The whole program costs just $4.5 million (a drop in the bucket compared to typical space budgets)... and of course, it doesn't rely on expensive, heavy fuel to get around. If it proves successful, it would both make space exploration practical for more organizations and allow for long trips using smaller, nimbler vessels.