Solar Impulse flight: Across the US, powered by the sun

The experimental airplane Solar Impulse completed its first flight across the United States this week. The Swiss-made plane, powered only by the sun, is the first to make the trip both day and night without using conventional fuel. It started the journey on May 3 in California and ended on July 6 in New York. Pilots and creators Bertrand Piccard and Andre Borschberg took turns manning the single-seat flyer, which is powered by about 12,000 silicon solar cells and has a wingspan of a jumbo jet. The next step is a trip around the world in 2015. Workers load a wing of the Swiss sun-powered aircraft Solar Impulse into a Cargolux Boeing 747 cargo aircraft on February 20 at Payerne airport in Geneva. The Boeing will carry the Solar Impulse HB-SIA prototype aircraft to San Francisco for a series of flights across the US from the West to East Coast.