Bertrand Piccard, initiator of the Solar Impulse program, which is calling for a flight around the world with an aircraft powered exclusively by solar energy, showcased the state of his venture in a media conference at Duebendorf airfield near Zurich, Switzerland, last month.

Piccard made it clear that he intends for the flight of the Solar Impulse to be more than just another round-the-world adventure; he anticipates that it will provide an impetus for increased use of solar power in a number of other fields. Nicolas Hayeck, co-initiator of the low-energy Smart automobile, noted that increased use of solar power is an absolute necessity for sustained growth. Charles Edelstenne, chairman and CEO of Dassault; Joseph Ackermann, CEO of Deutsche Bank; and Christian Jourquin from Solvay all emphasized that solar power is a smart investment in the future.

The four-engine Solar Impulse, presented by CEO and chief designer André Borschberg, is a basic aircraft but its 200-foot wingspan would befit an airliner. The shape of the airplane has changed since the initial presentation and now features a box-shaped fuselage and a drooped nose. The single-seat non-pressurized cockpit has no heating and no air conditioning, but there is sufficient thermal insulation to keep the pilot comfortable.

The aircraft is designed to fly at a cruising altitude of up to 27,500 feet in sunlight and gradually descend to about 10,000 feet at night, and then climb back to 27,500 feet after sunrise during several 36-hour flight legs around the world at low speed. The rollout is scheduled for next fall.

Once flight testing with the first aircraft is completed, a second that incorporates improvements will be built and used for a round-the-world trip in 2011.