Test and training flights will continue ahead of an attempt at the record-setting around-the-world flight, scheduled to take place in March 2015.
"The route has not been fully defined yet," a spokesperson said via email. "We know that we will fly in order over the Arabian Sea, India, Myanmar, China, the Pacific Ocean, the United States, the Atlantic Ocean, and southern Europe or North Africa, before closing the loop by returning to the point of departure."
In 1999, Piccard took part in the world's first non-stop around-the-world hot air balloon flight. The balloon burned through 3.7 tonnes of liquid propane in nearly 20 days, with just 40 kilograms left when it landed.
"In a situation like this one, dependency to fuel, to fossil energy, is not a theory; it's a feeling in your gut," he said, recalling the experience in an online press video.
"On that day, I made a promise that the next time I would fly around the world, it would be with no fuel."
Solar aviation started in the 1970s. An early manned flight - in a glider boosted by an electric motor and a helicopter battery - took place in California in 1979. Two years later, a solar-powered plane named Solar Challenger flew from Paris to London.
The Solar Impulse project is backed by investors Solvay, Omega, Schindler, ABB, Google, Altran, Bayer MaterialScience, Swiss Re Corporate Solutions and Swisscom.
Like what you see? For weekly Element news sign up to our newsletter. We're also on Facebook and Twitter.
