APOD 3.2

http://apod.nasa.gov/apod/ap110128.html

 

NanoSail-D (Jan. 28 2011)

               Though this photo is only an artist's illustration, it still gives a realistic portrayal of NASA's NanoSail-D. The NanoSail-D has just unraveled a very thin, ten square meter reflective sail on January 20th, becoming the first solar sail spacecraft in low Earth orbit. Though to many people this has just been considered a far off dream, sailing through space was suggested about four hundred years ago by Johannes Kepler who observed comet tails blown by the solar wind. Modern solar sail spacecraft designs, like NanoSail-D or the Japanese interplanetary spacecraft IKAROS, rely on the minute but continuous pressure from sunlight itself for thrust. Glinting in the sunlight as it circles planet Earth, the NanoSail-D solar sail will periodically be bright enough to be easily visible to the naked eye. In fact, sky gazers are being urged to participate in an ongoing contest to capture images of the reflective sail. NASA stated that the images will help monitor the satellite before it reenters the atmosphere in April or May.