See also Pocket Spacecraft: http://pocketspacecraft.com/ http://pocketspacecraft.com/ These are mylar disks about the size of a CD with circuitry and solar pa

See also Pocket Spacecraft: http://pocketspacecraft.com/ http://pocketspacecraft.com/ These are mylar disks about the size of a CD with circuitry and solar panels printed directly onto them, with a metal stiffening wire around the edge that doubles as the antenna. They're planning on launching hundreds via a three-unit cubesat mothership. Last year they ran a Kickstarter to try and get a swarm of these into lunar orbit; they didn't make their goal, but they're going ahead anyway. They mass substantially less than a gram each! They're so light they reckon that they'll survive reentry into Earth's atmosphere; if you buy one, you get your name and address printed on it so that if someone finds it they can post it back to you...