IKAROS - an acronym for Interplanetary Kite-craft Accelerated by Radiation Of the Sun - was launched May 21 to test how a very thin, very large membrane can be used much like a sail on ship. Rather than wind, the craft relies on the slight but ever-present force of photons from the sun.
The idea for solar sailing dates back more than 100 years ago and there have been several attempts to test the technology in space. IKAROS, with its 20-meter diagonal sail, is the most ambitious mission to date.
IKAROS also draws electricity from thin film solar cells embedded into the sail, power that can be used to operate an ion propulsion engine for added acceleration. JAXA plans to test the sail over the next five months, as the spacecraft heads to Venus. Of particular interest is whether the satellite's spin can keep the 0.0075 mm-thick sail flat and fully extended.
(Field work, in space. Credit: JAXA)