The Solar Impulse prototype solar aiplane has been developed by Swiss engineers. It is has the 193-foot wingspan, about the width of a standard jetliner, but weighs no more than an average car. Placed on top of its wings are about 12,000 solar panels, which provides the aircraft with a renewable energy source.

Project President and pilot Bertrand Picard recently took the Solar Impulse out for a test flight and hopes to complete its first around the world flight in 2014.

There is still a long way to go before the round-the-world flight, reads a statement on the Solar Impulse Project website. A second airplane is at present under construction, it will be capable of standing up to long-duration missions in changing meteorological conditions. The pilot has to have a safe, high-performance cockpit that will allow him to endure flights lasting several days. An even more effective man/machine interface has to be developed, and a reliable, light-weight communications system trialled that will enable the largest possible numbers to share the adventure in real time.

Have a look at the Solar Impulse HB-SIA prototype below: