So far the plane to be used by 47-year-old psychiatrist Bertrand Piccard exists only in the computers of the researchers at the Lausanne polytechnic, where a team of about 50 scientists are working on the 40-million-euro project, funded by four sponsors who so far remain in the shadows.

But Piccard, grandson of explorer and pioneer aeronaut Auguste Piccard who provided the inspiration for Professor Calculus in the Tintin comic books, is determined his dream dubbed Solar Impulse will get off the ground.

His ambition is "to use a great human and scientific adventure to help sustainable development and the survival of our planet.

"Our greatest problem is managing to store enough solar energy during the day to be able to fly at night," he told reporters.

Completely autonomous

The plane, also called Solar Impulse, will be completely autonomous even during take-off and will be able to fly above the clouds reaching heights of over 10,000m.

Made out of light but incredibly strong carbon-fibre, it will weigh only 1500kg, some 400 times less than an airliner. But it will have a giant wing-span stretching some 80m - much longer than an Airbus.

The entire structure, which will look like a giant mosquito, will be covered in 240 square metres of solar panels to capture and store the sun's power.

And four high-output electric motors will use the energy to power slowly rotating propellers, measuring several metres across.

First trials

Researchers believe Solar Impulse, which could carry two pilots, will be able to cruise at around 120km an hour at 10,000m. The first trials are set for 2007.

"This project brings together my scientific background with my love of adventure and exploration"

Bertrand Piccard,
Swiss adventurer

"The first test-mission will be the first flight at night," said Piccard, already imagining himself at the controls of his ground-breaking plane.

His plan is then to fly around the world in stages, leaving from Europe and landing again in the Gulf. The next stage would be from the Cape to southern China, then across the Pacific to California.

Then a flight across the United States to New York. And finally to Paris following in the wake of aviator Charles Lindbergh, who in 1927 in his plane Spirit of St Louis became the first to make the non-stop solo flight from New York to the French capital.

Love of adventure

A love of adventure is in Piccard's bones. His grandfather, Auguste, in 1931, with his associate Paul Kipfer, made the first manned balloon flight into the stratosphere.

Auguste Piccard designed a special pressurised aluminium gondola for the flight, which he later realised could be adapted to explore the depths of the ocean, dubbing the first deep sea submersible he designed the bathyscape.

Auguste's son, Jacques, the father of Bertrand, then improved on the machines and in 1960 descended in Trieste to the deepest-known point on Earth, the Challenger Deep in the Mariana Trench, making the deepest dive in history to 10,915m.

"This project brings together my scientific background with my love of adventure and exploration," said Piccard.

"Solar Impulse will be a platform for launching more discussions on sustainable development and the technologies which will allow it to happen."