LightSail is a solar sail project developed by The Planetary Society, a global non-profit organization devoted to space exploration. LightSail is a three-unit CubeSat about the size of a loaf of bread. LightSail and Prox-1 will be released into an orbit with an altitude of 720 kilometers (450 miles), high enough to escape most of the planet’s atmospheric drag. Prox-1 will eject LightSail into open space. Later, it will assemble with LightSail and inspect it. When LightSail unfurls its solar sails, Prox-1 will be nearby to capture images of the big moment.