{"copyright":"Ralf Vandebergh","date":"2026-01-02","explanation":"In 2011, on Ja nuary 20, NASA's NanoSail-D2 unfurled a very thin and very reflective 10 square meter sail becoming the first solar sail spacecraft in low Earth orbit. Often co nsidered the stuff of science fiction, sailing through space was suggested 400 y ears ago by astronomer Johannes Kepler, who had observed comet tails blown by th e solar wind. But modern solar sail spacecraft designs, like NanoSail-D2, Japan' s interplanetary spacecraft IKAROS, or the Planetary Society's Lightsail A, rely on the small but continuous pressure from sunlight itself for thrust. Glinting in the sunlight as it circled planet Earth, NanoSail-D2's solar sail was periodi cally bright and visible to the eye. These remarkably detailed images were captu red by manually tracking the orbiting solar sail spacecraft with a small telesco pe.","hdurl":"https:\/\/apod.nasa.gov\/apod\/image\/2601\/NanosailD2_reprocessed 1a.png","media_type":"image","service_version":"v1","title":"NanoSail-D2","url": "https:\/\/apod.nasa.gov\/apod\/image\/2601\/NanosailD2_reprocessed1a1024.png"}
