Planetary Society to launch solar sail test flight in May

A tiny spacecraft designed to be pushed through space by ultra-thin "solar sails" will be launched inMay by a U.S.-basednon-profit group, 10 years after its first failed attempt.

The Planetary Society announced Monday that its LightSail spacecraft will blast off on a test flightaboard an Atlas V rocket. The society is a non-profit space advocacy organization co-founded by the late astronomer Carl Sagan and headed by Bill Nye, best known as the Science Guy from his popular TV show.

The LightSail spacecraft,a tiny cube satellite about the size of a loaf of bread,is expected to unfurl its four solar sails in June. The triangular sails are made of Mylar, about a quarter of the thickness of a garbage bag, and have a combined area of 32 square metres equivalent to two parking spaces.

Solar sails are designed to capture the momentum from solar energy photons using large, mirrored surfaces. The small, continuous acceleration allows a spacecraft propelled by solar sails to reach high speeds over time.

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"As LightSail breezes around the Earth, its shiny sails will be visible from the ground," the Planetary Society sayson its website for the project.

According to a blog post byJason Davis, the society's digital editor, the spacecraft won't fly high enough to escape Earth's atmospheric drag and demonstrate "true" solar sailing.

But it will gather time-lapse images of the sails' deployment and engineering data that show how they perform in microgravity.

That, in turn, will be used to prepare for a second flight in 2016, at a higher altitude of 720 kilometres that will demonstrate "true solar sailing."

The Planetary Society is collaborating on the project withCalifornia Polytechnic State University and theGeorgia Institute of Technology, which will help collect data from the spacecraft,and two private space technology companies, Stellar Exploration Inc., which built the spacecraft, and Ecliptic Enterprises Corp., which conducted flight testing.

The Planetary Society tried to launch the world's first solar sail, Cosmos 1, in 2005, but the launch vehicle failed and it never reached orbit.

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Five years later, the first solar sails were deployed by Japan's Venus-bound IKAROS spacecraft and NASA's NanoSail-D satellite in low-Earth orbit.

NASA has two upcoming solar sail missions, one to the moon and the other to an asteroid, scheduled for 2018.