Solar Impulse crossing Atlantic

Piccard launched from John F. Kennedy International Airport at 2:30 a.m. local time (6:30 a.m. UTC) hoping to reach Seville Airport in Spain June 23, marking the first transatlantic voyage by an aircraft powered exclusively by the sun. Requiring an estimated time of 90 to 110 hours, this crossing would be nearly three times the duration of Charles Lindbergh's famous aviation first, though the team noted many commonalities between the two, including the capacity to inspire people to embrace new technology. Co-founder André Borschberg previously claimed the records for the longest solar-powered aircraft voyage, in terms of both distance and duration, crossing from Japan to Hawaii in July 2015, a five-day voyage that pushed the aircraft’s battery system to—and beyond—its limits, requiring a months-long delay in Hawaii for repairs and upgrades before the journey around the world resumed in April.

“The current situation is perfect,” an engineer told Piccard nine hours into the flight, which was being broadcast live online. That transmission was related to the aircraft’s charging system; the flight also appeared to be 52 minutes ahead of schedule, based on another transmission. Piccard was flying relatively low, 3,390 feet, at that stage, and posted a Twitter message remarking on the beauty of whales he had spotted jumping in the ocean below.

“Just like the whales below me, #Si2 depends only on nature,” Piccard noted on Twitter.

The around-the-world expedition, funded primarily by corporate sponsorships and donations, aims to inspire more widespread use of solar technology.

“With this flight over the Atlantic, we are further demonstrating Bertrand’s vision that clean technologies work and can be applied everywhere. We can now make our world more energy efficient,” Borschberg said in a news release announcing the June 20 launch. “It’s not a question of technology anymore, it’s only a question of mindset: Solar Impulse is like a flying smart grid, and if we can make it work in an airplane, where we can’t cheat, we can make it work on the ground, in our cities, for our homes and for all applications.”

Nine hours into the flight, the batteries were 83 percent charged. June 20 was also the the longest day of the year in the northern hemisphere, giving Piccard and the team the maximum benefit of free energy; the weather also appeared to be cooperating.