LightSail A . ... Credit Copyright: The Planetary Society Explanation: Hitching a ride to low Earth orbit, LightSail A accomplished a challenging test mission, unfurling its 32 square meter mylar solar sail on June 7. This dramatic image from one of the bread loaf sized spacecraft's fisheye cameras captures the deployed sail glinting in sunlight. ... But modern solar sail designs, like the one tested by LightSail A rely on the small but continuous pressure from sunlight itself for thrust. ...