Solar-powered Impulse takes flight once again over the San Francisco skies

Solar Impulse embarked this morning on its latest journey, departing the San Francisco Bay Area at dawn, heading toward Phoenix on the first leg of a trip that if all goes well will land the sun-powered airplane in New York City around the Fourth of July.

Piloted by Bertrand Piccard, the super-lightweight airplane with a 208-foot wingspan slowly took flight from Moffett Airfield south of San Francisco at 6:12 a.m. Pacific Daylight Time. “Good bye to the Silicon Valley after 2 very interesting monthes in the world of innovation” tweeted Piccard an hour or so after setting out for Arizona. By the time he gets to Phoenix, after a full day of flying, it is expected to be around midnight. Here’s video of this morning’s preparations and takeoff:

Solar Impulse and its adventures have been compared variously to the first flight of the Wright Brothers and Charles Lindbergh’s crossing of the Atlantic, but here’s one big difference: The world can follow this trip at it happens with streaming video and a Web interface that includes the usual flight data – airspeed, heading, altitude – along with some information unique to Solar Impulse: solar generator power, battery status and engine power.

Screen grab of the Solar Impulse live streaming page, two hours into Bay Area-Phoenix trip

During his flight this morning, Piccard said that the most difficult aspect of the Bay Area to Phoenix trip would be navigating through busy airspace. “I have to be very precise,” Piccard said, bouncing back and forth between interviews and conversations with air traffic controllers and his own ground crew. At the time, Piccard was at 8,200 feet altitude, heading toward 21,000 feet.

The Solar Impulse project was founded by Piccard and André Borschberg, who will pilot portions of the North America trip that, after Phoenix, will include stops in Dallas, St. Louis and Washington, D.C.

Last year, the team made a triumphant trip from Europe to Africa that included a 448-mile leg from Madrid to Salé, Morocco.

Ultimately, Piccard and Borschberg hope to circumnavigate the globe in a new Solar Impulse craft, with a bigger, more comfortable cockpit, based on the HB-SIA they are taking across the North America after successful flights last year in Europe.

They were pointing at 2014 for that global attempt, but when the wing spar on the under-development HB-SIB was damaged in construction, they pushed the round-the-world flight to 2015 – and that’s when the decision was made to bring the HB-SIA to the U.S.

The revolutionary carbon fiber solar airplane has 12,000 solar cells built into its wings that recharge a set of four 400-kilo lithium batteries housed in the engine pods during flight. The plane averages about 8 horsepower—similar to what the Wright Brothers managed when they first flew in 1903.

* Pete Danko, EarthTechling