This is innovation at its best. Scientists at JAXA (the Japan Aerospace Exploration Agency) not only created a satellite with solar sails (something poor guys at the planetary society will probably be fuming at) but created an innovative method to control its attitude, not by using rocket motors but a simple liquid crystal display. Yes this is the same stuff used to make the displays in your calculators and watches!
The liquid crystal device on the craft is a thin-film instrument that changes the surface reflection characteristics of sunlight by turning on and off the power of the device.
Location of the LCDs on the IKAROS craft, Image Courtesy: JAXA
For the uninitiated, a solar sail works just like an ordinary wind-sail. The major difference being that instead of wind, it uses pressure generated by incident light radiation from the sun. When electromagnetic radiation is incident on a solid, it exerts a small force on the target, that may cause it to move. Solar sails ave potential application in deep space missions, as the maximum theoretical speed gained from a solar sail is the speed of light!
The difference in solar pressure is used to generate torque and re-orient the spacecraft.
The IKAROS was launched from the Tanegahima Space Center on May 21, 2010.
Related Links:
How Solar Sails work
Planetary Society Solar Sail Initiative
