Right now, a solar-powered aircraft is soaring over Pacific waters from Kalaeloa, Hawaii to Mountain View, California — without one drop of fuel on board. The experimental Solar Impulse 2 plane, created by Swiss company Solar Impulse, that weighs about the same as the standard family car, took off from the tarmac at 4:15 p.m. UTC today to embark after a nine-month maintenance stay in Oahu. The 62 hour flight to the Bay Area is Solar Impulse’s ninth leg in a journey around the world.

The company built Solar Impulse 2 to be the first craft to ever complete a round-the-world flight with just the power of the sun’s rays. By achieving this, Solar Impulse hopes to demonstrate “the potential clean technologies have for energy saving and renewable energy production,” the company website says.

The flight started a little over a year ago on March 9, 2015, embarking on its first leg from Abu Dhabi to Muscat, Oman — a trip that took 13 hours. The plane made pit stops in India, Myanmar, China, and Japan before making its five-day and five-night flight to Hawaii. However, during the 117-hour and 52-minute flight, the rechargeable batteries overheated from human error, causing extensive damage that took nine months to repair.

Solar Impulse 2 flies solely on energy from the sun during the day and stores reserve supplies for the morning and evening hours in batteries which have to be 100-percent charged to make it throughout the night. The craft has the same wingspan of a Boeing 747 Jumbo Jet, except the upper wings are covered by a skin of 17,248 ultra-thin monocrystalline silicon solar cells that collect up to 340 kilowatt hours of solar energy per day. This powers an engine that has the power of a small motorcycle — reaching speeds between 22 to 87 mph. Luckily, the engine only has to support 5,070 pounds of lightweight carbon fiber and alveolate foam that makes up the frame in the body of the plane, cockpit, and spars.

Solar Impulse 2 is covered in micron-thin solar cells.

The company was founded 12 years ago by Bertrand Piccard and André Borschberg, with Piccard currently piloting Solar Impulse 2 to the West coast. Solar Impulse’s aircraft has already set eight world records, including being the first solar airplane to fly throughout the night, between two continents, and across the United States. After Solar Impulse 2 touches down in Mountain View, it will make three more stops in the United States and another in Southern Europe or Northern Africa before it completes its global flight in Abu Dhabi.

Solar Impulse's round-the-world flight route map. 

While there are other solar-powered aircrafts in the works, Solar Impulse 2’s round-the-world flight will be a remarkable feat for renewable energy technology if it reaches Abu Dhabi.

“Solar Impulse was not built to carry passengers, but to convey messages,” Bertrand Piccard wrote on the company’s website. “We do not plan to revolutionize the aviation industry but instead to demonstrate that the actual alternative energy sources and new technologies can achieve what some consider impossible.”

You can follow Solar Impulse 2’s journey to Mountain View live here.