"Hold your hands out to the sun. What do you feel? Heat, of course. But there's pressure as well – though you've never noticed it, because it's so tiny. Over the area of your hands, it only comes to about a millionth of an ounce. But out in space, even a pressure as small as that can be important – for it's acting all the time, hour after hour, day after day. Unlike rocket fuel, it's free and unlimited. If we want to, we can use it; we can build sails to catch the radiation blowing from the sun."

These words were spoken not by a NASA scientist but by a fictional character – John Merton – in Arthur C. Clarke's short story The Wind from the Sun. If all goes well, Merton's prophetic words are about to become fact.

NASA researchers, thinking "out of the box" (or maybe "out of the rocket") have long dreamed of the possibility of sailing among the planets with sails propelled by sunlight instead of by wind. Except in works of fiction, though, no one has yet successfully deployed such a sail anywhere beyond Earth.

"There's a first time for everything," says Edward "Sandy" Montgomery of NASA's Marshall Space Flight Center.

Montgomery's team and a team from Ames Research Center (led by Elwood Agasid) hope to make history this summer by deploying a solar sail called NanoSail-D. It will travel to space onboard a SpaceX Falcon 1 rocket, scheduled for launch from Omelek Island in the Pacific Ocean during a window extending from July 29th to August 6th (a back-up extends from August 29th to September 5th)