Solar sails use the sun’s energy as a method of propulsion—flight by light. Light is made of packets of energy called photons. While photons have no mass, a photon traveling as a packet of light has energy and momentum. Solar sail spacecraft capture light momentum with large, lightweight mirrored surfaces—sails. As light reflects off a sail, most of its momentum is transferred, pushing on the sail. The resulting acceleration is small, but continuous. Unlike chemical rockets that provide short bursts of thrust, solar sails thrust continuously and can reach higher speeds over time.The Planetary Society reported on the initial success of the launch, noting:
The first of The Planetary Society’s two LightSail spacecraft is now in space following a late morning launch from Cape Canaveral Air Force Station in Florida. Liftoff occurred at 11:05 a.m. EDT (15:05 UTC). The Centaur upper stage and primary payload are in their preliminary orbit, with LightSail and its CubeSat companions bolted near the aft section in the secondary ULTRASat payload. LightSail spacecraft separation is expected to occur at 1:05 p.m. EDT.Spacecraft separation also went without a hitch and the mission is well underway. You can continue to track the progress of mission by going here. If all goes well, a second, full mission will take place in 2016.
Update: If you would like to contribute to the 2016 Lightsail mission you can do so via Kickstarter. As of May 23rd, the site has garnered more than $700,000 in pledges, which is excellent since the goal was only $200,000.
Second Update: The Planetary Society has declared the Lightsail mission to be a success, even with the multiple communication glitches. You can listen to the press conference on the mission here.
