Solar-powered plane’s global trek a milestone for clean technology

age fatigue during the long solo flights, Borschberg practised yoga and Piccard self-hypnosis.

In a statement this week, Borschberg said it was no longer a question of whether it was possible to fly without fuel or polluting emissions.

‘‘By flying around the world thanks to renewable energy and clean technologies, we have demonstrated that we can now make our world more energy efficient,’’ he said.

The pilots would rest a maximum of 20 minutes at a time, repeating the naps 12 times over each 24-hour stretch.

It took 70 hours for Piccard to cross the Atlantic Ocean, which was the first by a solar-powered airplane.

Borschberg’s flight over the Pacific Ocean at 118 hours – five days and five nights – shattered the record for the longest flight duration by an aircraft flying solo.

Neither pilot was able to stand in the cockpit while flying, but the seat reclined for stretching and its cushion could be removed for access to a toilet. Goggles worn over the pilot’s eyes flashed lights to wake him, while armbands underneath their suits buzzed when the plane was not at flying level. The plane also did not have a pressurised cockpit.

Hot temperatures in the Middle East this time of year cause thermals and turbulence that forced Piccard to fly longer periods of time with an oxygen mask as he piloted the last leg of the trip.