Weather front halts sun-powered plane on marathon Pacific flight

Deteriorating weather has forced the Solar Impulse, the plane aiming to fly around the world powered only by the sun, to postpone its effort to reach Hawaii and to plan a landing instead in Japan.

"Weather window toward Hawaii has deteriorated," the support crew said. "We decided to make an intermediate landing in Nagoya!"

Nagoya is a Japanese city about 200 miles west of Tokyo.

The trip to Hawaii was said to be the toughest leg of the Solar Impulse's round-the-world voyage. It was scheduled to take five days -- with just one pilot -- and to use no fuel at all.

The 8,000-kilometer (4,971-mile) journey from Nanjing, China, to Hawaii -- dubbed the "moment of truth" by alternating pilots Andre Borschberg and Bertrand Piccard -- had already been delayed several times because of poor conditions over the Pacific.

But in the early hours of Sunday (Saturday afternoon, ET), Solar Impulse embarked on the ambitious leg of the journey.

Mission Director Raymond Clerc said the route would see Solar Impulse fly over South Korea and northwest of Japan before heading out across the Pacific, and may take slightly longer than planned -- potentially landing in Hawaii on the evening of Day 6.

But it wasn't to be. On Monday morning the flight went into a holding pattern as a weather front blocked its path toward Hawaii.

"Yesterday we had the possibility to cross the weather front just before Hawaii on day 5. However, with the forecasts we now have, we don't see this possibility anymore, which means that for the moment the road to Hawaii is blocked," the team said in a emailed statement.

"We have asked André to stay where he is: It's fine, the weather is good and the batteries are charging. During this time we will analyze where he will have to go to find a possibility to cross that front."

Former fighter pilot Borschberg, who would have been at the controls alone for the entire 130-hour flight, had expressed excitement for the flight after weeks of holdups.

Borschberg, who also flew from Abu Dhabi to Oman in March on the first leg of the plane's 35,000-kilometer, five-month journey, said the latest journey would be "the flight of my life."

He planned to spend the entire trip in the 3.8-cubic-meter cockpit, strapped into a special seat that serves both as bed (it reclines, allowing him to do essential exercises and to rest) and toilet.

At night, if there was no turbulence, Borschberg would have been able to activate the autopilot and nap, but only for 20 minutes at a time.

He and Piccard have been trained in meditation and self-hypnosis to allow them to concentrate for lengthy periods, and yoga to help them relax in the plane's confined space.

Solar Impulse was packed with enough food, water and sports drinks to meet Borschberg's nutritional needs for a week, in case weather problems meant it had to stay in the air longer than expected.

The aircraft was also equipped with oxygen bottles, a parachute and a life raft in case it gets into trouble and Borschberg has to ditch midflight.