NANJING, China — It takes a Boeing 747 about 10 hours and 36,000 gallons of fuel to fly from eastern China to Hawaii. As soon as Tuesday, André Borschberg will attempt the same flight in a high-tech, sun-powered aircraft that resembles a dragonfly. He'll do it over five days, without a drop of fuel.

No one before has attempted a solar-powered flight over such a large expanse of ocean – 5,070 miles. If bad weather or other problems force him to ditch his Solar Impulse plane, Borschberg will have only his wits and a life raft to save him.

Borschberg acknowledges the dangers. So does his fellow Swiss adventurer, Bertrand Piccard, who flew the single-seat plane to China in April and is slated to fly it from Hawaii to Phoenix later this month.

"Yes, we are nervous. I am nervous also," Piccard said in an interview in Nanjing. "But more than anything, we are impressed. We're in awe of the enormous distance over water that we have to do: André for the first part, and me for the second part."

Piccard and Borschberg hope to be the first pilots to fly a solar-powered plane around the world. After 12 years of planning, networking and fundraising, they launched their tag-team expedition in March, flying from the United Arab Emirates to Oman, and then on to India, Myanmar, Chongqing, China, and Nanjing.