Solar Plane Passes Big Test, Flies 24 Hours Straight

ZURICH, Switzerland (July 8) -- A solar-powered plane successfully completed a crucial round-the-clock test flight today in the skies over Switzerland, with its inventors hailing it as a milestone for aviation using only the clean and renewable energy of the sun.

The carbon fiber Solar Impulse prototype, with the 262-foot wingspan of an Airbus A340 and the weight of a midsize car, landed after 26 hours in the air at 9 a.m. local time, completing the world's first night flight with a solar plane.

As the delicate silhouette of the aircraft prepared for touchdown at the Payerne airbase near Bern, a crowd of fans, media representatives and members of the Solar Impulse team who made the mission possible, erupted into cheers. The plane had taken off shortly before 7 a.m. Wednesday, with a solo pilot at the controls.

The aircraft flew across Switzerland for over a day to allow its 12,000 solar panels to soak up as much energy as possible, charging the batteries enough to keep the plane aloft through the dark of night.

"Everything went very well, it's really unbelievable," an elated pilot, Andre Borschberg, said shortly after exiting the bathtub-sized cockpit. "We demonstrated it is feasible to fly day and night, which means this technology can be used to save energy and to produce energy, and that's exactly what we wanted to show."

Borschberg, CEO and co-founder of the Solar Impulse project, brought the plane up to an altitude of 28,000 feet during the day and cruised gently until the sun's rays begin to weaken about two hours before sunset. The aircraft then started a slow descent to 5,000 feet and then flew until the morning, the team said.

Borschberg said sunset and dawn were the best moments of the flight, thanks to the "gorgeous colors reflecting on the wings."

"When the sun rose, I saw the solar generators slowly getting back to active, so I thought, hmm, it's alive again! And I knew I could continue flying for another day," Borschberg told AOL in a telephone interview. "It was so beautiful. When you're passionate about flying, you can just keep on doing it."

After landing, the aircraft stood on the runway for a few minutes as the technical team rushed to stabilize it and help the pilot out.

"When you took off it was another era," a visibly emotional Bertrand Piccard, co-founder of the project, told Borschberg after exchanging a long hug as they stood near the cockpit. "Now you land in an era where people understand that with renewable energy you can do impossible things," said Piccard, who initiated the project in 1999 following his own circumnavigation of the world in a balloon.

A successful day-and-night cycle was a vital step toward the ultimate goal of traveling around the world. The mission marked the longest and highest flight ever by a solar plane. This summer, the team plans to construct a slightly larger version of the aircraft that would stay in the air for up to five days, landing only to switch pilots.

The Solar Impulse team initially scheduled the night flight for earlier this month, but a technical problem involving a transmitter forced the group to reschedule.