The Solar Impulse 2 isn't your average aircraft: it's been designed from the ground up with this mission in mind. Over 17,000 solar cells line its wings, supplying a series of electric motors and charging four on-board lithium batteries. It's designed to be entirely solar-powered, and, thanks to those batteries, able to fly through day and night. While we've certainly seen solar planes before, it's the first that can actually fly between continents — and, if all goes well, it'll soon be the first to fly around the world.
The trip is due to take place over five months. It's starting and finishing in Abu Dhabi, with around 25 full flight days split into twelve legs. As such, the craft is unlikely to be breaking speed records any time soon, but to the minds behind the project, Swiss aviators Bertrand Piccard and André Borschberg, that's not the point. For them it's the energy efficiency of the project that makes it exciting. They're not so concerned with changing the aviation industry just yet, so much as changing the public perception about how exciting renewable energy can be. In other words, this is as much publicity stunt as technological milestone.
Boasting just one seat (with a built-in toilet) and a cabin that has neither heating nor oxygen, it's likely to be a rough ride, so it's no wonder the pilots have chosen to break the flight down into such small chunks. What's more, with in-flight food tastily described as "dehydrated and vacuum-packaged" the pilots may well find themselves desperately longing for the dubious sludge that so infamously makes up economy meals.
In short, this plane is still a huge stretch away from the cushy fuel-hungry Boeings and Airbuses we know and love, but its clear message on the potential of renewable energies could have a serious impact on the future. Despite industry scepticism about the future of solar panels on aircraft, if the round-the-world flight is a success it may well be enough to reopen the debate about the future of fuelling our aircraft. Regardless, we just hope that while solar panels may one day line the wings of our aircraft, the toilets stay out of the passenger seats and remain in their designated cubicles.
Image credit: Solar Impulse