The first aircraft designed to run exclusively on solar power was introduced near Zurich, Switzerland after spending six years in stealthy development. Record-setting hot air ballooner Bertrand Piccard plans to take the plane, dubbed the Solar Impulse, on several test flights by the end of the year, demonstrating that air travel is not off limits when it comes to cleantech innovation.
The craft, made out of lightweight carbon fiber and shaped like a wasp with the wingspan of a Boeing 747 jumbo jet (207 feet), was built so that it can continue flying at night, even in the absence of the sun. If the Solar Impulse makes the first trek in the anticipated two days and one night without incident, the technology will be adapted for a second, slightly different solar plane to be completed and flown around the world in 2012.
Weighing less than a mid-size car (3,306 pounds), the Solar Impulse only seats one passenger. Sunlight is absorbed by about 12,000 solar cells distributed across its wings. It is then used to power four 10-horsepower compact electric motors — and what isn’t used immediately is stored in 882 pounds of batteries. This reserve energy is used to keep the plane aloft at night. If the plane performs correctly during an initial daytime flight, Piccard plans to take it on a continuous 36-hour flight to prove the efficacy of its battery systems.
The Swiss plane is not the only solar-powered aircraft in the works. NASA has been working on its Helios for several years, and Qinetiq is closing in on its Zephyr model. The latter came close to being the first — completing an unmanned 54-hour flight in 2007 — but no cigar.
Piccard says he first got the idea for the Solar Impulse back in 1990 when he successfully circumnavigated the globe in a hot air balloon.