By Vincent Fribault
PAYERNE, Switzerland (Reuters) - A giant glider-like aircraft has completed the first night flight propelled only by solar energy, organizers said on Thursday.
Solar Impulse, whose wingspan is the same as an Airbus A340, flew 26 hours and 9 minutes, powered only by solar energy stored during the day. It was also the longest and highest flight in the history of solar aviation, organizers said.
Bertrand Piccard, the Swiss president of the project, best known for completing the first round-the-world flight in a hot air balloon in 1999, said the success of the flight showed the potential of renewable energies and clean technology.
"We are on the verge of the perpetual flight," he said.
Jubilant pilot Andre Borschberg told Reuters television: "It was unbelievable, success better than we expected. We almost thought to make it longer, but ... we demonstrated what we wanted to demonstrate so they made me come back, so here I am."
Borschberg, a former Swiss air force pilot who has flown for 40 years, returned to a hero's welcome at Payerne air base in the northwestern canton of Vaud, where hundreds gathered at dawn to watch the aircraft glide onto the Tarmac at 0700 GMT (3 a.m. EDT).
The carbon-fiber aircraft reached a maximum speed of 68 knots (ground speed), an average speed of 23 knots and a maximum altitude of 8,564 meters above sea level, a statement said.
"The success of this first night flight by a solar-powered plane is crucial for the further course of the Solar Impulse project," it said.
The Solar Impulse HB-SIA, which has 12,000 solar cells built into its 64.3-meter (193-foot) wings, is a prototype for an aircraft that its creators hope will carry out its first circumnavigation of the globe from 2012.
The next milestone will be crossing the Atlantic using a second prototype which goes into construction soon.
Weighing just 1,600 kg (3,500 lb), as much as a medium-sized car, the plane powered by four electric motors is designed to save energy from its solar cells in high-performance batteries.
Sponsors of the project, whose budget is 100 million Swiss francs ($95 million), include Belgian chemicals company Solvay SA, Swiss watchmaker Omega, part of the Swatch group, and German banking giant Deutsche Bank. France's Altran is the project's engineering partner.
(Additional reporting by Jesse Morgan; Writing by Stephanie Nebehay; Editing by Janet Lawrence)