“It’s a project for energy, for a better world”

solar impulsePilot Bertrand Piccard relayed these words to journalists before Solar Impulse 2 took off under his control from Cairo shortly after midnight on Sunday on the final leg of its round-the-world journey. Prince Albert gave the green light from Mission Control in Monaco with the words: “You are released to proceed.”

The solar-powered aircraft had been due to leave Egypt earlier in the week, but its departure was held up due to a combination of strong winds and a bout of ill-health that hit Piccard. The project’s other pilot, André Borschberg, earlier set a world record for the longest uninterrupted journey in aviation history in a leg that took 118 hours.

The aircraft is all the more remarkable because it usually flies at 30 mph, a speed that doubles when its photo-electric cells are exposed to full sunlight.

Before take-off, Piccard said: “It’s a very, very hot region … it’s going to be an exhausting flight.” A psychiatrist by profession, Piccard made the first non-stop navigation of the globe in a hot air balloon in 1999.

With a flight time expected of 48 hours, Solar Impulse is due to return to Al Bateen Executive Airport in Abu Dhabi Monday.