Though it may look like a collection of tinfoil and string, the photo above depicts what may be the first solar sail to actually propel a spacecraft. Japan's IKAROS (Interplanetary Kite-Craft Accelerated by Radiation of the Sun) just unfurled the 7.5 micron (.0003-inch) thick polyimide membrane 7.4 million kilometers from Earth this week, and expect its embedded thin-film solar panels to propel the craft past Venus and towards the dark side of the sun. Because wax and feathers only get you so far.


IKAROS successfully stretches wings, prepares for solar spaceflight