TOPSHOTS Sun-powered plane Solar Impulse 2 HB-SIB is seen in silhouette during his first exit for test on April 14, 2014 in Payerne a year ahead of their planned round-the-world flight. Solar Impulse 2 is the successor of the original plane of the same name, which last year completed a trip across the United States without using a drop of fuel. AFP PHOTO / FABRICE COFFRINI