Smooth Sailing for Spacecraft

http://news.bbc.co.uk/2/hi/science_and_environment/10328584.stm

Images from a tiny camera confirm that the solar sail on Japan's Ikaros spacecraft has been deployed. The 200-square-meter sail is essentially a thin, mirrored sheet that will propel the spacecraft using radiation pressure from the Sun. While the idea of solar sailing has been around for decades, it has never been successfully proven on this large a scale.

The Japanese Space Agency (JAXA) hopes to detect a measurable acceleration in the spacecraft as photons, or particles of solar radiation, fall on the sheet. They will also attempt to change the direction of Ikaros by altering the angle of the sail.