Swiss adventurer André Borschberg has broken the world record for the longest solo flight aboard his Solar Impulse 2 aircraft.

Borschberg has been at the controls of the Solar Impulse 2 for more than 80 hours and 5,663 kilometers (about 3,500 miles) without refueling since taking off from Nagoya, Japan, and he still has another 40 hours of flying to do before he touches down in Honolulu, Hawaii.

The previous record of 76 hours was set by American adventurer Steve Fossett when he circumnavigated the globe aboard the Virgin Atlantic Global flyer in 2006. The Nagoya-to-Honolulu flight is the 13th stage of Borschberg's attempt at the first round-the-world trip in a solar aircraft. The Solar Impulse 2 has already broken all distance and duration world records for solar aviation.

Borschberg has been now flying alone in an unheated and unpressurized 3.8 cubic meter one-seater cockpit for three consecutive days and nights. "The first 24 hours were very technical but the second day was really getting me into the mission," Borschberg said from his cockpit high above the Pacific Ocean. "The experience of flight is so intense that I can only focus on the present moment and discover how to deal with my own energy and mindset," he added. The Swiss pilot has been able to get small snippets of rest by using the aircraft's autopilot for 20-minute periods, though he admitted it took him a while to trust the system.

All going well, Borschberg will get some proper sleep and a good break when he lands in Hawaii after 120 hours of toil. His companion, fellow Swiss explorer Bertrand Piccard, will fly the plane for the next leg of the trip to Phoenix, Ariz. From there the pair will take turns crisscrossing the U.S. before continuing across the Atlantic Ocean toward Abu Dhabi, where they set out from on March 9. Those interested in his progress can track the flight live here.

Apart from breaking records the main purpose of the journey is to raise awareness for the Future Is Clean initiative, which is petitioning governments to use clean, renewable technologies and plans to bring its message to the United Nations Climate Change Conference, COP21, in Paris in December. Piccard and Borschberg founded the organization but have received backing from global names like Mikhail Gorbachev, Richard Branson, Kofi Annan and Prince Albert of Monaco.

Borschberg and Piccard founded Solar Impulse in 2003 and have already broken numerous records piloting the Solar Impulse 1 aircraft, including the first solar night flight and the first intercontinental flight from Switzerland to Morocco.

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