From high above the Pacific, Solar Impulse 2 pilot spreads Earth Day message

Speaking from the cockpit of Solar Impulse 2 as it makes its journey over the Pacific, pilot Bertrand Piccard told that that solar-powered plane proves the immense potential of clean technology.

“Clean technology is a huge opportunity that will create jobs, make profits and protect the environment,” he said, via phone.

Solar Impulse took off from Hawaii Thursday on the ninth leg of its fuel-free journey around the world. The plane is expected to complete its 2,336-mile flight to Moffett Airfield, Mountain View, Calif. at around 3 a.m. ET Sunday.

Related: Solar Impulse 2 takes off from Hawaii, continues epic solar-powered journey

The 62-hour journey, which is the second-longest solar-powered flight in aviation history, also coincides with Earth Day Friday. “It’s very symbolic to be flying during Earth Day,” Piccard said. “This year Earth Day is a very active day - it’s the day when the heads of state are signing the Paris Climate agreement.”

“If everything goes well, I have a satellite connection with the U.N. to explain the message of Solar Impulse,” he added.

Speaking about 3 hours into the flight, Piccard described the view of clouds and ocean from the Solar Impulse 2 cockpit as “gorgeous.”

Related: Solar Impulse 2 reaches Hawaii, shatters records in historic Pacific flight

“I am feeling much better now in the air than on the ground,” he said, explaining that the wait for perfect flight conditions in Hawaii was nerve-wracking. “This morning, it was stressful, there was too much wind – it was a relief to take off.”

The plane's ideal flight speed is about 28 mph, though that can double during the day when the sun's rays are strongest. The carbon-fiber aircraft weighs more than 5,000 pounds, or about as much as a minivan or midsize truck.

The wings of Solar Impulse 2, which stretch wider than those of a Boeing 747, are equipped with 17,000 solar cells that power propellers and charge batteries. The plane runs on stored energy at night.

Related: Solar Impulse 2’s epic journey in pictures

“You need to manage the energy of the airplane by loading the batteries the best possible during the day,” said Piccard.

The pilot also acknowledged the physical and mental demands of flying for 62 hours in a single-seat cockpit that is too small to stand in. “I am using a lot of self-hypnosis to regenerate mind and body,” he said.

The plane is the brainchild of explorer and Solar Impulse Chairman Piccard, who is taking it in turns with his fellow Swiss pilot Andre Borschberg to fly the aircraft on its journey across the globe.

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Borschberg piloted the previous leg of Solar Impulse 2’s journey - an incredible 4,480-mile, five -day flight from Japan to Hawaii. The 118-hour trek shattered the record for longest solar-powered flight both in terms of distance and duration.

Piccard told that he is thrilled to pilot Solar Impulse 2 to Mountain View, which is in the heart of Silicon Valley. “Silicon Valley is really a place for innovation – everyone there tries to do better things with technology … they love Solar Impulse because it goes into this spirit of thinking and doing things differently,” he said. “Landing 150 meters from Google’s HQ is fantastic.”

The incredible solar-powered trek began in March 2015 when Solar Impulse 2 took off on the first leg of its journey from Abu Dhabi to Oman. Solar Impulse 2 then made stops in India, Myanmar and Nanjing, China, en route to an unscheduled stop in Nagoya, Japan. The plane originally left Nanjing, China, for Hawaii, but diverted to Japan because of unfavorable weather.

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Solar Impulse 2 reached Hawaii on July 3 2015 but the next leg of the journey was delayed for nine months while the Solar Impulse team repaired damage to the plane’s batteries

After reaching California Solar Impulse 2 is slated to make stops in the midwest and New York before flying over the Atlantic Ocean. It will then stop in southern Europe or North Africa, depending on weather conditions, before ending its epic journey in Dubai.

Follow James Rogers on Twitter @jamesjrogers

The Associated Press contributed to this report.