Geneva -- Round-the-world ballooning pioneer Bertrand Piccard unveiled his solar-powered aircraft in Switzerland on Friday, ready for another trip across the globe powered only by the sun.

The wasp-shaped prototype of Solar Impulse, with the wingspan of a jumbo jet, was displayed to some 800 guests at an airfield near Zurich after six years of development.

Ten years after Piccard and Briton Brian Jones achieved the first non-stop flight around the globe in the Orbiter balloon, the Solar Impulse team aim to demonstrate that reliance on renewable energy is possible.

"If an aircraft is able to fly day and night without fuel, propelled solely by solar energy, let no one come and claim that it is impossible to do the same thing for motor vehicles, heating and air conditioning systems and computers," Piccard said.

Although computer simulations have been tested, the prototype HB-SIA will make its first test flight by the end of 2009.

Its mission is to test the possibility of a complete flight sequence through two days and one night, powered only by solar energy, and facilitate a second aircraft's flight around the world in five stages in 2012.

The Swiss adventurer -- who is again joined by Jones -- said the idea emerged after that 19-day hot air balloon trip, when Orbiter was partly kept up by fuel canisters.

"That historic success could have turned sour because of the lack of fuel," Piccard said at the Dubendorf airfield.

"That's why we took the decision to attempt a trip around the world without relying on fossil fuels," he explained.

The new technology has a 63.4 metre wingspan but weighs as much as a medium-sized car.

Some 12,000 solar cells spread over its wings keep it aloft, fuelling small ten-horsepower electric motors and 400 kilogrammes of batteries that will keep it working overnight.

In the narrow cockpit, the pilot will also be helped to fly Solar Impulse by new control technology.

"Those are the wings of hope. They are immense, as is the challenge we have to meet in climate protection," said Swiss Transport, Energy and Environment Minister Moritz Leunberger.

AFP / Expatica