Navigating the heavens by ‘sailing’ on the solar wind is the aim of the Planetary Society with their planned 2010 launch of their LightSail-1 spacecraft. The propulsion system is the ultimate in sustainability and economy since, after getting into orbit on the rocket, it uses absolutely no fuel, unlike conventional spacecraft and rockets.
The Planetary Society’s hope is that the momentum transfer of the photons on the Mylar will help increase the velocity of LightSail-1, making it gain in altitude. The Planetary Society will be measuring the orbit velocity using ground telescopes and onboard sensors. The acceleration will be tiny, only 0.06mm/s2 (0.0024 inch/s2) but over 100 days this adds up to 14,000kph (12,760mph), and over 3 years the velocity gets to 241,000kph (150,000mph).
The LightSail-1 spacecraft is consists of 3 Cubesats forming an electronic control module, sensors and cameras, with the third holding the solar sail. After piggyback release from the launcher at 800kms (497miles), the four Mylar solar sails are deployed, providing 32m2 (344sq.ft.) of sail that is designed to capture photons from the solar wind. The sail is only 4.5 microns (0.18 mil) thick, about one-quarter the thickness of a plastic trash bag. It weighs only 5kg (11lbs) and is 30cmx10cmx10cm (11.8x3.9x3.9inch) in size.
If LightSail-1 performs as expected, then LightSails 2 and 3 are planned as future longer duration missions. The ultimate hope is that solar sails can be used to boost spacecraft orbits, or de-orbit them, for positional station-keeping, travel within our solar system, and beyond. Once past Jupiter the solar energy is much reduced so the idea would be to boost the solar sail using lasers focused on the sail from within the solar system.
Visit: http://www.planetary.org/home/
Trevor Williams is a University of Victoria Mechanical Engineering PhD candidate specializing in renewable energy, power grid modeling and plug-in hybrid electric vehicles. He has a bachelors in Aeronautical Engineering, a Masters in Management Science and over 23 years international experience in the space industry, having worked on Earth observation and telecommunications satellites. He is the author of the Eco-Geek blog.
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