The Solar Impulse aircraft, a pioneering

The Solar Impulse aircraft, a pioneering Swiss bid to fly around the world on solar energy takes off on its first test flight on April 7, 2010 from Payerne's air base, western Switzerland. Propelled by four 10 horsepower electric motors, the gangling single-seater aircraft and test pilot Markus Scherdel slowly gained altitude for a scheduled flight of around two hours at an altitude of around 1,000 metres (3,280 feet). The tests are due to build up to a first non-stop 36-hour flight through darkness, followed by a five-stage flight around the world in 2012. AFP PHOTO/POOL/ FABRICE COFFRINI (Photo credit should read FABRICE COFFRINI/AFP via Getty Images)