CLEAN TECH:

Swiss team to launch solar night flight

Who needs fuel?

A Swiss pilot is expected to take to the skies as soon as tomorrow in a plane outfitted with 12,000 solar cells glued to its wings. He will be looking to the sun to power his aircraft, during both the light of day and the dark of night.

The mission, weather permitting, will mark the world's first manned 24-hour solar flight.

In a specially designed plane with a 63.4-meter wingspan -- roughly the size of a Boeing 747 jumbo jet -- and a weight carefully slimmed down to be about that of a family car, André Borschberg plans to give aircraft a new benchmark.

"This flight is representing the first important milestone to demonstrate how to use solar energy to fly at night and get closer to the notion of perpetual flight," he said in an interview. The flight will be a steppingstone, he hopes, to flying around the world without any fuel.

The ultralight plane, called the Solar Impulse HB-SIA, uses its solar cells to feed four electric engines and to recharge lithium batteries contained in pods tucked beneath the wings.

The plane itself is little more than a glider, traveling at an average speed of about 44 mph and hoping to soar up to an altitude of some 26,000 feet. But adding more solar cells or battery power is out of the question -- then the plane would be too heavy, Borschberg said, noting that the batteries amount to about a quarter of the aircraft's weight.

After soaking up the sun's rays all day, Borschberg plans to gently guide the plane down to 5,000 feet during the night, waiting for dawn and for the batteries to begin to recharge from the sunrise.

"I think the most exciting part will be to wait for the sunrise, and there will be a big suspense, because that proves you can fly for the entire night," Borschberg said. "One thing which is unbelievable is you fly during the day, and the more you fly, the more energy you get in the airplane," he said.

The challenge will not be staying awake all night, he said -- "the difficult thing will be to concentrate because it needs to be piloted at all times." That means he has to pace himself and relax, he said. And with little room to move because of the tiny cockpit, Borschberg said part of his training, in addition to flight simulations, has been doing yoga and practicing breathing exercises to relax and help his blood flow.

The flight comes after the 70-person crew of the project suffered a setback last week on the eve of the targeted launch date for the flight. During a checkup on the plane, it was discovered that the electronics responsible for some of the major communication and flight configuration control of the plane had overheated and needed to be replaced. But after getting some spare parts, the new launch date appears to be on track for tomorrow.

Last December marked the first time the plane left the ground, but at that point, it could venture little more than 2 feet off the ground and only traveled less than 1,000 feet at a stretch. Since then, however, it's come a long way -- with at least 10 test flights so far, the craft has soared up to more than 28,000 feet and managed to stay aloft for up to 14 hours.

Now, armed with an iPod mix of his favorite songs from the 1960s and 1970s and a playlist put together by his friends and family, Borschberg, 57, plans to squeeze into the plane, which is only big enough for one, juicing up the lithium batteries through solar cell power all day and crossing his fingers that the electric motors can power through until dawn the next day.

If the flight is a success, Borschberg, who has been a pilot for 40 years, and his partner on the project, around-the-world balloonist Bertrand Piccard, 52, are hoping to break another barrier: global flight through solar power. They are setting their sights on a flight over the Atlantic next year and hopefully a global flight -- with multiple stops -- in 2013.

Through carefully embedded cameras, viewers can also watch the trip itself and observe Borschberg live on the website, scanning the power gauge, which will tell Borschberg if things are not going as planned. Though Borschberg says he feels "confident" that he would have the opportunity to land should problems arise, he also has a parachute lined up as Plan B -- just in case.

"Our main message is not to say everybody in five years will be flying with solar power. The technology is not there for that," Borschberg said. Indeed, the team identified a 10-day window in which they would take the maiden night flight, waiting for optimal sunny weather before they do their first full-night voyage, and technical glitches prevented them from taking off on their first planned launch date.

But Borschberg and Piccard say the flight will prove it is possible to fly without any pollution. Moreover, Borschberg said it will "motivate governments and politicians to take more actions to favor this kind of energy in the future."

The vision

The future of aviation may be some sort of hybrid technology that would allow planes to be fueled by biofuels and solar-power collectively, Borschberg believes, but it is unlikely that solar power will allow airlines to phase out fuel tanks anytime soon -- or possibly ever.

Still, proving that a plane could be flown by tapping the sun's rays may mean that governments and the public will be less reluctant to look to the technology to power cars and heaters and air conditioners, Piccard said. "This project voices our conviction that a pioneering spirit with political vision can together change society and bring an end to fossil fuel dependency," he said in a statement.

"If an aircraft is able to fly day and night without fuel, propelled only by solar energy, let no one claim that it is impossible to do the same for motor vehicles, heating and air conditioning systems and computers," he said, noting that the flight is propelled by 40 horsepower, roughly that of a scooter.

Seven years after the team started looking into the technology, and with roughly $90 million of investment from backers including Solvay, Omega and Deutsche Bank, the two adventurers are optimistic. After Piccard accomplished the first balloon trip around the world and barely had enough fuel to reach the coast of Africa, "that's when the idea started to have technology to fly without fuel" and therefore move away from our dependence on fossil fuels, Borschberg explained.

With this solar flight, we're saying, "If a plane can do it, so can machines on the ground."

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