Solar Impulse 2 flying over Switzerland during test flights in 2014. Photo courtesy Solar Impulse/Revillard/Rezo.ch
NANJING, China, May 25 (UPI) -- The Solar Impulse 2, a completely solar-powered aircraft that was set to make its most difficult leg of its around-the-world journey, canceled at the last minute amid bad weather.
The plane, the first of its kind to make such a journey, is readying to make a six-day trip across the Pacific Ocean from Nanjing to Hawaii. Solar Impulse flight control said worsening conditions across the Pacific made the crossing too dangerous.
"The trend of unstable weather in the Pacific has taken a toll for the worse," Solar Impulse officials said on the website. "A combination of factors put this flight at risk, including cloud levels reducing charging capacity and considerable holding and loitering times to get through the front may have forced a seven-day flight, pushing the pilot to excessive extremes.
Just moments before the cancellation, pilot Andre Borschberg, a Swiss engineer and former fighter pilot, remained optimistic about the trip. Borschberg gave this leg of the journey a name: "The moment of truth."
"I am feeling a bit high, actually, in the sense that we have been working hard to find a window for many weeks," Borschberg told CNN on Monday, before the flight was unexpectedly aborted.
Borschberg and business partner Bertrand Piccard, a Swiss psychiatrist and explorer, have been flying the plane since departing Abu Dhabi, United Arab Emirates, in March.
The aircraft has been grounded in China for weeks after landing there for a planned overnight stop on April 21. The project team estimates the trip across the Pacific would take up to six days. The trip is arduous. The cockpit isn't pressurized so the pilots must wear oxygen masks. At night, they can only sleep in 20-minute increments. Overall the journey will cover nearly 22,000 miles and will take an estimated five months.