Solar Impulse 2, a plane powered only by the sun, takes off from Kalaeloa, Hawaii, USA, on the ninth leg of its around-the-world journey. This portion of the trip will cover 2,542 nautical miles and, in about three days, is scheduled to touch down in Mountain View, California. The journey originated in Abu Dhabi, United Arab Emirates, on March 9, 2015, and, after another 8,130 nmi, will complete the circle when it lands in Abu Dhabi.