LightSail Spacecraft Test Mission Ends With Fiery Reentry

Following its 25-day cruise in low-Earth orbit, LightSail, an experimental solar sail propulsion system launched by The Planetary Society, expectedly fell from its orbit and broke apart in the Earth’s atmosphere.

The small boxlike structure was launched into space in May, blossoming into a 32-m² spacecraft when its thin reflective plastic sail was deployed. Solar sailing works by using sunlight for propulsion. When solar photons struck LightSail’s reflective sails, their momentum was transferred to the spacecraft, gradually accelerating it through space. While the push from photons was minuscule, it was continuous and unlimited. Solar sails could eventually reach greater speeds than those obtained by chemical rockets.

LightSail captured an image of its deployed solar sails in orbit on June 8. Photo courtesy of The Planetary Society.

LightSail was never expected to escape the Earth’s atmospheric drag; the goal of the testing period was to study its solar sails. LightSail was packaged into a small spacecraft called CubeSat, which has made low-cost space missions a reality for universities and research groups.

This test mission, known as LightSail-A, is to be followed next year by the launch of LightSail-B, a nearly identical sail-equipped nanosatellite that should fly high enough to demonstrate how sunlight can be used to steer the spacecraft in addition to propelling it.

The Planetary Society CEO William Sanford Nye (“Bill Nye the Science Guy” to most) hopes that LightSail will provide evidence that solar sailing can serve as a low-cost method to send small spacecraft anywhere in the solar system.

“We are advancing space science and exploration,” Nye said. “This mission is part of our mission. The best is yet ahead.”