A prototype solar-powered airplane completed several important tests last Thursday and Friday.

Solar Impulse's HB-SIA, which was finished this past summer, taxied down a runway using power from the 11,000 solar cells covering its wings and did a series of acceleration and braking tests. The next test will be revving up the plane to its 35km/hour take-off speed.

Founder of Solar Impulse, Bertrand Piccard, a former astronaut and the first man to circle the world nonstop in a balloon, hopes to perform the same feet in a solar-powered plane derived from on the HB-SIA design. Solar Impulse aims to test the prototype in flight next year and to achieve a 36-hour flight without fuel shortly after that. Results from these tests will be used to build a solar-powered plane to will attempt a transcontinental flight sometime after 2012.

A number of solar-powered aircraft exist already, such NASA's Helios, the Solar Riser glider or the Sunseeker which flew across the US in 1990 using a mix of solar power and gliding.

The Solar Impulse prototype is made of lightweight materials, weighing only 3,500 pounds and it has a wingspan of 210 feet. It is intended to fly at only 28 miles per hour to keep energy consumption low. It will store solar energy for night flight.