AIR & SPACE MAGAZINE LightSail 2 Launches to Space to Soar on the Power of Sunshine The Planetary Society’s second solar sail will attempt to use sunlight to fly through space June 25, 2019 Though photons do not have mass, they do transfer momentum when they reflect off a reflective space sail, giving it a slight boost. Raquel Scoggin / Supercluster Get the latest stories in your inbox every weekday.