Solar sails, like that unfurled by the IKAROS spacecraft this summer, catch photons from the sun the same way a boat sail catches the wind. But because these sails are large, rigid, metal structures, they are difficult to steer. Now physicists have found a way to better control them. The team shined a 130 milliwatt beam of light on a 10 micrometer-long, wing-shaped piece of glass floating in water. Because glass bends light, a property known as refraction, the wing moved perpendicular to the light rays at a rate of a few micrometers per second, as seen in this video. Adding wings made of glass or other refractive materials in flight would allow astronomers to better steer future space missions, the team reports online today in Nature Photonics. So a craft won't be stuck if it needs to make a U turn.
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