In 1931, a Swiss explorer named Auguste Piccard took a record-breaking balloon flight to over 50,000 feet in the air. A few years later, he realized that modifying his balloon cockpit could create a new kind of cockpit—a bathyscaphe—that is capable of descending deep into the ocean.
This May, his grandson Bertrand Piccard will extend his grandfather’s legacy of exploration, piloting a completely solar-powered airplane across the U.S., from San Francisco to New York City, over the course of two months (the plane will make four stops along the way). Just as his grandfather’s balloon cockpit led to unexpected deep-sea innovation, the plane, dubbed Solar Impulse, is already having effects outside the aerospace industry. Because let’s be honest: a solar-powered plane isn’t very practical.
Piccard launched the Solar Impulse project in 2003, just a few years after completing a round-the-world balloon flight. "I realized that everything I do is dependent on fossil energy. I almost failed the balloon flight because of a lack of fuel with me, so I thought, 'Next time I’ll make it without fuel.'" So Piccard set up a feasibility study led by engineer and pilot André Borschberg, who is now co-leading the project.
Despite all the obstacles in the way of building a solar airplane that can fly during the day and at night—namely, that no one had ever done anything like this before—Piccard and Borschberg created a prototype that they began testing in 2009. They received financing and technology from a number of private companies, including Deutsche Bank, Omega SA, Solvay, Schindler, Bayer MaterialScience, and Toyota. All of the technologies developed and improved upon for Solar Impulse, says Borschberg, were created with the idea that they could also have other applications.
"We’re not saying we’ll fly solar-powered commercial airplanes soon. That’s not the goal. It’s about stimulating innovation for clean technology and energy," explains Piccard.
The reason why outside companies clamored to get involved is simple: it’s good press, and an opportunity to test their technologies in a unique environment.
So the polyurethane rigid foams used in the plane’s wingtips, motor gondolas, and cockpit—developed by partners Solvay and Bayer MaterialScience—are being used in refrigerators and construction because of their insulating properties. In the future, Solvay imagines that the foams could be used more generally in airplanes. "More than half the refrigerators sold around the world will use this material," says Borschberg.
The second version of the plane (set to circumnavigate the globe in 2015) has four high energy density lithium ion batteries, manufactured by Kokam, that can be found in cars, smartphones, tablets, and other electronics. The composite materials developed by Decision SA may soon be found on boats. There’s even a matchbox-sized EKG worn on the pilot’s chest (created by EPFL) that measures the pilot’s fatigue. Eventually, it could end up in cars.
Even with all of these innovations onboard, many of which didn’t exist just a decade ago, Solar Impulse still isn’t an easy plane to fly. It’s extremely light, so it’s sensitive to turbulence and wind. That means it needs to take off and land in calm weather, and the plane can’t fly at all through big thunderstorms. It’s nothing like flying a normal plane, according to Piccard: "If you fly it like a normal airplane you overcontrol, you cannot steer and land. You need to learn how to be extremely careful, make little moves with the control, and wait until a reaction comes. You have to anticipate enormously, and it’s not very stable, so you need to fly with the rudders." Rudders are used on normal planes only in specific circumstances, like landing in crosswinds.
In the first prototype of the plane, which was recently reassembled for flight in the San Francisco Bay Area, there’s no autopilot, no toilets, and nowhere for a pilot to lie down and sleep. The next version of the plane will have all of that—along with better reliability and technical improvements that make a global trip possible.
The cross-country Solar Impulse flight is expected to take off May 1 with Borschberg and Piccard at the controls, weather dependent. You should be a little jealous. "When you fly with no fuel, you know theoretically you can fly forever,' says Piccard. "It’s a feeling of freedom."