Solar Impulse project co-founder Andre Borschberg (R) checks from his helicopter as German test pilot Markus Scherdel steers the solar-powered Solar Impulse 2 aircraft during its maiden flight at its ... more 
Solar Impulse project co-founder Andre Borschberg (R) checks from his helicopter as German test pilot Markus Scherdel steers the solar-powered Solar Impulse 2 aircraft during its maiden flight at its base in Payerne June 2, 2014. The aircraft, which was unveiled April 9, weighs 2.4 tons with a wingspan of 72 meters (236 ft.) and more than 17,000 solar cells. The attempt to fly around the world in stages using only solar energy will be made in 2015, according to the project. REUTERS/Denis Balibouse (SWITZERLAND - Tags: TRANSPORT ENVIRONMENT SCIENCE TECHNOLOGY) less 
1 / 26
Reuters | Photo By DENIS BALIBOUSE / REUTERS
Mon, Jun 2, 2014 2:45 AM EDT