Solar Plane Attempts 24-Hour Test Flight
Weighs as much as a car, with the wingspan of an airliner
By Caroline Miller,  Newser Staff
Posted Jul 7, 2010 6:12 AM CDT
Solar Impulse's CEO and pilot Andre Borschberg takes off in the solar-powered HB-SIA prototype airplane for its first night flight attempt at Payerne airport Wednesday, July 7, 2010.    (Denis Balibouse)
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(Newser) – An experimental solar-powered plane whose makers hope to one day circle the globe using only energy collected from the sun took off for its first 24-hour test flight today. The plane, which weighs about as much as a car but has a 262.5-foot wingspan, left Payerne airfield in Switzerland shortly before 7am after overcoming an equipment problem that delayed a previous attempt. Clear blue skies mean the prototype aircraft will be able to soak up plenty of solar energy as it flies over the Jura mountains to the west of the Swiss Alps.

By midmorning pilot Andre Borschberg was cruising at 9,850 feet, trying to avoid low-level turbulence and thermal winds that are frequent in the mountains. He will take the plane to an altitude of 27,900 feet by this evening, when a decision will be made whether to continue through the night using solar power stored in its batteries. This test flight—the third major step after its first "flea hop" and an extended flight earlier this year—will demonstrate whether the ultimate plan is feasible: to fly the plane around the world. "This flight is crucial for the credibility of the project," said team co-founder Bertrand Piccard, a record-breaking balloonist whose father and grandfather also accomplished pioneering airborne and submarine feats.