Two Swiss pilots have set off on an historic mission to fly around the world in a solar-powered plane.

Leaving from Abu Dhabi this morning, the remarkable attempt by Andre Borschberg and Bertrand Piccard in the Solar Impulse 2 is a global first. They will carry no fuel at all.

And if successful, the pair will surely usher in a more environmentally-friendly era of air travel, which is awesome news for those of us who love long-haul adventures but often feel guilty about the carbon footprint of such big trips.

The voyage is expected to last five months and cover a distance of 35,000km. Most flight legs will last around 12 hours though some of the longer oceanic sections, including China to Hawaii and Hawaii to Arizona, will see the pilots flying for five days at a time. In a cockpit smaller than an average car boot!

A small cockpit was one of the concessions made to keep the plane as light as possible, another was the fact the pilot’s seat also functions as a toilet and small bed, though hopefully not at the same time…

The plane weighs just 2,268kg, which is the same as some SUV cars. A regular glider plane weighs around 850kg. The biggest challenge for the engineers was making the plane as big as possible to maximise the solar cells, for power and thrust so the plane could take off and maintain altitude, while retaining a low weight.

The plane will have 17,000 solar cells, each as thin as a human hair, with a wing span of 72m, which is wider than that of the Boeing 787-8, which carries 420 passengers.

The Solar Impulse 2 is expected to fly up to 28,000 ft to gain maximum sunlight but that means the pilots will face extreme cold and possible altitude sickness. Piccard, who is a trained psychiatrist, plans to use self-hypnosis and yoga to keep himself calm and to cope with the long hours of flying.

The pair also packed energy drinks, protein bars, onboard oxygen, parachutes, a life raft and according to one of the more bizarre reports a pair of black UGG boots. One can only presume the Aussie sheepskin fashion brand paid a lot of money to the project for that plug.

Such brand involvement is perhaps to be expected given that the project was funded purely from private investment with no backing from the aviation industry, who Borschberg says do not have the technology to build such a craft.

Both Piccard’s grandfather and father were explorers. His grandfather was the first person to reach the stratosphere in a pressurised capsule carried by a balloon and his father descended to the deepest part of the seafloor. Piccard told journalists:

“When you see what my father and grandfather did, it was not to make a record. It was to be useful. Exploration has to be useful. This is why I launched this project. I think we can make a huge difference.”

We hope they can too.

Watch a live feed from the Solar Impulse 2 control room here: