Round the World on Solar Power

You might remember the solar-powered plane Solar Impulse from its state-hopping flight across the US last year, and subsequent party tour across the nation’s airport hangars. It was an impressive feat: the plane flew across the country without refuelling once (albeit at an achingly slow pace), relying only on the sun for its power.

But now her younger sister has come to put that feat to shame: Enter Solar Impulse 2, which has its solar panels set on circumnavigating the globe in a 35,000km trip with 500 hours flight time.

That record attempt is set for 2015, and continues a rich history of exploration ingrained in project leader Bertrand Piccard’s family. His father was the first to explore the deepest part of the ocean, while his grandfather was the first to make a round-the-world hot air balloon trip. Now, Piccard and his team plan something of a 21st century, clean tech version of that project.

Like its predecessor, Solar Impulse 2’s wings are covered in photovoltaic panels that will produce solar energy to both power its motor and store in batteries—so it can make it through the nights. That’s crucial because the plane isn’t going to be overtaking any jumbo jets any time soon; the mission stretches over five months and 20 days of flight time, with the plane landing every few days to exchange pilots between Piccard and co-founder André Borschberg.

In some stages, however, the plane will be in the air for four to six hours at a time to cross the oceans. So as well as a technical upgrade, this version attempts to have a few more creature comforts, like space for food and somewhere to pee. A convertible seat to toilet might not sound like the height of luxury, but at least there’s room to lie back and relax over those night flights (as much as its possible to relax when you’re on your own in an experimental flying machine, days from land, with no fuel).

Officially named HB-SIB owing to its Swiss aircraft code, the new plane has an improved tech spec from HB-SIA. It can actually fly in the rain—useful for long stretches where weather can change—thanks to isolated electrics, and its battery density is increased. With a wing span of 72m, it’s bigger than its predecessor and just wider than a Boeing 747. It’s nevertheless incredibly light; made of carbon fibre, it weighs just 2,300kg, a quarter of which is taken up by batteries.

The plane is scheduled to set off in March 2015 from somewhere in the Persian Gulf and head eastwards.

Of course, the main point of the trip is a PR stunt for renewables—which certainly isn’t a bad thing. It’s maybe also a chance for Piccard to pick up a few more “firsts” and carry on the explorer family’s legacy.