How Solar Impulse 2 became the first aircraft to complete a 40,000 km fuel-free journey around the world

When Solar Impulse 2 returned to Abu Dhabi in July 2016, it completed something that had never been achieved before. The aircraft had travelled around the world powered only by energy collected from the sun, finishing a journey of roughly 40,000 kilometres without using conventional fuel. It was not built to prove that commercial airliners could immediately switch to solar power. Instead, the project demonstrated that advanced engineering, lightweight materials and renewable energy could keep an aircraft flying across continents and oceans. The mission lasted 16 months, with weather delays and long stopovers shaping the route, yet it ultimately became one of the most recognised demonstrations of clean-energy technology in aviation.How Solar Impulse 2 completed the first fuel-free flight around the world The aircraft began its round-the-world expedition after departing Abu Dhabi on March 9, 2015. By the time it returned to the same city, it had covered approximately 40,000 kilometres while spending nearly 500 hours in the air.Rather than completing the mission in one uninterrupted journey, Solar Impulse 2 travelled in stages. The aircraft made 16 stopovers, partly because weather co...