Japan's Ikaros Spacecraft Successfully Propelled by Solar Sail Inhabitat - Green Design Will Save the World: "Each photon of light exerts 0.0002 pounds of pressure on the 3,000-square-foot sail, and one after another they succeeded in propelling the nearly 700-pound drone. Japanese scientists expect to be able to control IKAROS’s velocity by adjusting the angle at which incoming radiation strikes the sails. For a full technical explanation of how the drone is moving, check out the Japanese space agency JAXA’s press release."
