With its wings stretched wide to catch the sun's energy, a Swiss-made solar-powered aircraft took off from Abu Dhabi just after daybreak today in a historic first attempt to fly around the world without a drop of fossil fuel. Solar Impulse founder André Borschberg was at the controls of the single-seat aircraft when it lumbered into the air at the Al Bateen Executive Airport. Borschberg will trade off piloting with Solar Impulse co-founder Bertrand Piccard during layovers on a 21,700-mile journey. Some legs of the trip, such as over the Pacific and Atlantic oceans, will mean five days and five nights of flying solo.
The Solar Impulse 2 aircraft, a larger version of a single-seat prototype that first flew five years ago, has a wingspan of 236 feet, larger than that of the Boeing 747, although the solar aircraft is much lighter. Built into the wings are 17,248 ultra-efficient solar cells that transfer solar energy to four electrical motors that power the plane's propellers. The solar cells also recharge four lithium-polymer batteries. The Si2 is heading first to nearby Muscat, Oman, where it will land after about 10 hours of flight. A typical passenger jet takes just one hour to make the same journey. The plane will reach an altitude of around 28,000 feet during the day to catch the sun's rays and at night dip to around 5,000 feet when flying over the ocean. (Read more Solar Impulse stories.)