The flights are long because here’s another thing about Solar Impulse: It’s slow. Its cruising speed of just under 45 mph would get them honked at on an highway.
So that has meant a lot of 4 a.m. take-offs in the dark and landings well after midnight. But Borschberg, who will pilot the last leg from Washington to New York, is hoping for a daylight approach to New York City so he can get a photo opportunity with the Statue of Liberty.
Borschberg and Piccard both say this is not about clean-energy planes for the future. What they’re doing is more likely to improve energy efficiency on the ground, in cars and homes, agrees U.S. Energy Secretary Ernest Moniz who met with the pair to talk up future energy a couple days after they landed at Dulles.
Still, questions of practicality come up.
‘‘It’s clearly a stunt,’’ said John Reilly, co-director of MIT’s Joint Program on the Science and Policy of Global Change. ‘‘And it’s clearly an attention-grabbing stunt. The idea that you could fly an airplane powered by the sun is kind of hard to believe. So doing it is an impressive stunt, I suppose.’’
But these types of gimmicks do pay off at times, Reilly said.
It will pay off more than promoting solar and other renewable energy technologies as economic stimulus, which is what happened four years ago, said University of Colorado science policy professor Roger Pielke Jr. He compared it to giant prizes that encourage private companies to go into space or build robot-driven cars, which are proving successful.
‘‘I don’t think it’s just a stunt,’’ Pielke said. ‘‘The idea is that you’re pushing boundaries and you’re putting on shows for people and achieving milestones.’’
This, Pielke said, is ‘‘an essential part of technological innovation. It gives people an opportunity to attempt what previously was thought of as impossible.’’