The Swiss-made Solar Impulse plane made a smooth landing in Washington early Sunday, leaving just one more solar-powered hop to go in its cross-continent odyssey.
The 208-foot-wide (63-meter-wide) aircraft set down at Dulles International Airport at 12:15 a.m. ET, with Solar Impulse chairman Bertrand Piccard at the controls. The trip from Cincinnati Lunken Municipal Airport took more than 10 hours – an hour and a half longer than it would have taken to drive. But speed isn't the point. Rather, Solar Impulse is designed to demonstrate how solar power alone can take a plane across the country, and eventually around the world.
Although this trip didn't set any speed records, it did include a first-ever overnight "pit stop." Cincinnati was added to the itinerary just a few days ago when flight planners determined that cross winds and head winds would slow down the plane's progress too much to make it from St. Louis to Washington in one long stretch.
Andre Borschberg, Solar Impulse's CEO, flew the first leg of the trip – and then let Piccard take the second leg.
"The mobile hangar wasn't deployed during this short 11-hour pit stop – an unprecedented tactic in the history of the project – because it would have required too much time to set it up and take it back down," the Solar Impulse team said. "For the first time, the solar airplane was able to enjoy a starry night under the watchful eyes of its bodyguard, the ground crew."
Saturday morning's departure was delayed more than two hours due to fog at the Cincinnati airport. The condensation that was left behind on Solar Impulse's wings, which double as solar arrays, had to be laboriously wiped off by the crew before the plane's 10:11 a.m. ET takeoff. That delay didn't affect Piccard's arrival at Dulles: Aviation authorities had scheduled the landing after midnight to minimize interference with commercial air traffic, so there was already extra time built into the flight schedule.
Solar Impulse's "Across America" adventure is aimed at highlighting the plane's technologies for American audiences, and preparing the way for an even more ambitious round-the-world odyssey in 2015. The carbon-composite plane has the wingspan of a Boeing 747 jet but is as light as a passenger car. All of the plane's power is generated by the 12,000 solar cells mounted on the wings and horizontal stabilizer. Excess energy is stored in 880 pounds' worth (400 kilograms' worth) of batteries. That's what allows the plane to fly through the night.
Piccard, who was part of the first nonstop round-the-world balloon flight in 1999, said Solar Impulse's technologies could go commercial within the next five years. "Small solar airplanes flying in the daylight will come very soon to the market. ... All these technologies have a big, big future," he told an interviewer during an in-flight chat on Saturday.
The 10-year-old Solar Impulse project is backed by 90 million euros ($115 million) in investment by Swiss sponsors. Before coming to America, the plane went through a series of record-setting flight tests in Europe and Africa.
The American voyage officially began on May 3 with Solar Impulse's takeoff from Moffett Field in Mountain View, Calif., and continued with stopovers in Phoenix, Dallas and St. Louis. The journey is expected to end with a Washington-to-New York flight in early July, piloted by Borschberg.
Solar Impulse's organizers are offering a wide array of outreach activities — including an open house at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center at Dulles on Sunday afternoon. Energy Secretary Ernest Moniz is due to meet up with the Solar Impulse crew for a roundtable and news conference on Monday.
Piccard said he saw a "dual significance" to being in Washington.
"On the one hand, it proves the reliability and potential of clean technologies, and this is crucial in pushing our message forward," he said. “On the other hand, to be hosted by the Smithsonian Institution is an honor for Solar Impulse. The capsule of my around-the-world balloon flight is already displayed in the Air and Space Museum — and I hope one day a second Swiss aircraft will join the collection."
For updates on the project, follow @SolarImpulse on Twitter.