FIGURES & FACTS$7 mn crowd-funded venture1.7 km is the distance by which the spacecraft has raised the orbital high point In the past four daysThe idea of solar sailing was first theorised in the 1600s by German astronomer Keplar who wrote that sails and ships could be adapted to heavenly breezesLightSail 2 puts it into practice via a sail made from Mylar that unfurls to a size of 32sq metersThe Planetary Society's team demonstrated a proof of concept for a new form of propulsion that could one day transform deep space exploration by doing away with the need for expensive rockets and fuel. As packets of light energy known as photons (light particles) bounce off the sail, they transfer their momentum in the opposite direction, pushing the vessel along with an unlimited thrust. LightSail 2 doesn't have the precision to maintain a circular orbit. So as its apogee rises, its perigee decreases, exposing it to atmospheric drag that will overcome the thrust from solar sailing. LightSail 2 will continue to orbit for about a year before falling back into Earth's atmosphere.