After a successful flight across the U.S. in 2013, followed by a series of tests in Switzerland last June, the Solar Impulse 2 plane soared into the skies above Abu Dhabi this morning to begin its historic round-the-world journey. 

The Swiss project, costing over $150 million and in development for 12 years, is the first single-pilot aircraft to fly day and night without a drop of fuel — thanks to the 17,248 solar cells that supply the electric motors with clean energy.

Despite a wingspan exceeding that of Boeing 747, the aircraft weighs less than a family car and boasts an efficient design that allows it to fly at altitudes as high as 27,000 feet — even at night. Unfortunately, all that efficiency comes at a cost, with a top speed of only 87 miles an hour. As a result, the 22,000-mile, round-the-world journey is expected to take anywhere from four to five months. 

The Solar Impulse website provides real-time updates on the aircraft's performance. (Photo: Solar Impulse)

Bertrand Piccard and Andre Borschberg, the minds and pilots behind the endeavor, say the Solar Impulse represents a demonstration of how green energy can be utilized to one day replace its fossil-fueled counterparts. While the technology is in its infancy, Piccard says there's historic precedent to what their trying to accomplish.

"It's a little bit like the Wright Brothers Flyer, 110 years ago," he told NBC News. "You know, the Wright brothers had no technology to fly with passengers. Nevertheless, after 20 years, the industry developed the system, and there could be passengers in airplanes. So we don't know. Maybe it will happen like this with Solar Impulse."

Unlike the time of the Wright brothers, you can follow along online as history is made with the Solar Impulse. The official website features real-time updating on both the aircraft's flight plan, electric generation, and even the pilot's vitals. For the round-the-world journey, you can also view a live stream of the cockpit and mission control. 

The first leg of the journey, from Abu Dhabi to Oman, is expected to take 12 hours. Additional stops over the course of the journey will include India, Myanmar, China, Hawaii and several cities in the U.S.

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Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Solar Impulse begins historic flight around the world
Landmark $150M project is aimed at demonstrating the power of environmentally friendly technologies.