Photo taken on June 13, 2017 shows China's Caihong (CH), or Rainbow, solar-powered unmanned aerial vehicle (UAV) on its test flight. With a wingspan of 45 meters, the solar-powered drone by China Aerospace Science and Technology Corp is capable of flying at an altitude of 20 to 30 kilometers and has a cruising at a speed of 150 to 200 km per hour for long periods. The unmanned aerial vehicle will be used mostly for airborne early warning, aerial reconnaissance, disaster monitoring, meteorological observation and communications relay. (Photo: China News Service/Zhong Xin)