China's largest and most advanced solar-powered unmanned aircraft has set a domestic record for flight ceiling by reaching an altitude of over 20,000 meters, according to its designer. The Caihong, or Rainbow, solar-powered drone, developed by the China Academy of Aerospace Aerodynamics, set the record during a test flight last week at an unidentified airport in Northwest China. It flew at an altitude of 20,000 meters long enough for the flight to be classified as a success, Shi Wen, head of unmanned aircraft development at the academy, said in an exclusive interview on June 1, 2017. He said the drone took off in the morning and flew back to the airport late at night. It will take several years for designers and engineers to improve and test the aircraft before it is delivered to users. (Photo/Weibo account of CCTV)