Bertrand Piccard and Andre Borschberg are on a mission to make history. To prove a point about the power of clean technologies and renewable energy sources, they are piloting the Solar Impulse 2 plane around the world using absolutely no fuel.
The plane, which is powered by the sun, weighs 5,071 lbs. (2,300 kg) and has a solar panel-covered wingspan of 236 ft. (72 m). Solar Impulse 2 set the record for the world’s longest solo flight at 4 days, 21 hours, and 52 minutes earlier this year while traveling from Japan to Hawaii.
Piccard and Borschberg started their journey in March and hope to finish by summer 2016. The plane is currently grounded through the winter to repair the batteries, but for the two pilots, the journey isn’t about how long it takes to cross the finish line. According to Piccard, “It’s not a race against time. It’s an attempt at making a historic first so the time it takes finally is not so important. What we need is to get back to the place where it started.”
See the World's Largest Solar Plants From Above
![Desert Sunlight where 8 million solar panels power 160, 000 California homes. Jamey Stillings for TIME](https://api.time.com/wp-content/uploads/2015/02/01_jamey_stillings_20150219_cp.jpg?quality=75&w=2400)
![Desert Sunlight Solar Farm produces 550 megawatts of energy, equal to the output of a conventional power plant, near Palm Springs, California, where. 8 million photovoltaic (PV) panels convert sunlight into electricity. Jamey Stillings for TIME](https://api.time.com/wp-content/uploads/2015/02/02_jamey_stillings_20150219_cp.jpg?quality=75&w=2400)
![The Crescent Dunes Solar Energy Project, a 110 megawatt solar thermal power project, near Tonopah, Nevada. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/03_jamey_stillings_20140626_cp.jpg?quality=75&w=2400)
![The Crescent Dunes Solar Energy Project, a 110 megawatt solar thermal power project, near Tonopah, Nevada. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/04_jamey_stillings_20140626_cp.jpg?quality=75&w=2400)
![Crescent Dunes Solar Plant, Tonopah, Nevada. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/05_jamey_stillings_20140625_cp.jpg?quality=75&w=2400)
![The Crescent Dunes Solar Energy Project, a 110 megawatt solar thermal power project, near Tonopah, Nevada. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/06_jamey_stillings_20140626_cp.jpg?quality=75&w=2400)
![Mirrored heliostats dot the landscape at the Ivanpah Solar Plant in the Mojave Desert, California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/07_jamey_stillings_20130321_bse.jpg?quality=75&w=2400)
![Construction of Ivanpah Solar Field One in the Mojave Desert, California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/08_jamey_stillings_20110421_bse.jpg?quality=75&w=2400)
![Heliostat installation at the Ivanpah thermal solar plant in the Mojave Desert, California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/09_jamey_stillings_20121027_bse.jpg?quality=75&w=2400)
![Mirrored Heliostats at the Ivanpah Solar plant in the Mojave Desert in California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/10_jamey_stillings_20130625_bse.jpg?quality=75&w=2400)
![Mirrored Heliostats that reflect and concentrate desert sunshine surround a tower at the Ivanpah Solar power station in the Mojave Desert, California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/11_jamey_stillings_20121027_bse.jpg?quality=75&w=2400)
![350, 000 mirrored heliostats reflect light onto boilers generating 392 megawatts of energy at the Ivanpah Solar power station in the Mojave Desert, California. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/12_jamey_stillings_20140924_bse.jpg?quality=75&w=2400)
![in the Mojave Desert, California. Unlike solar photovoltaic plants, which generate electricity directly from sunlight, Ivanpah uses hundreds of thousands of curved mirrors to reflect and concentrate the desert sunshine. Jamey Stillings](https://api.time.com/wp-content/uploads/2015/02/13_jamey_stillings_20130321_bse.jpg?quality=75&w=2400)
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Write to Julia Lull at julia.lull@time.com