Photo taken on May 24, 2017 shows a solar drone on its test flight. China has successfully tested near-space flight of its largest solar drone. With a wingspan of 45 meters, the solar-powered drone is capable of flying at an altitude of 20 to 30 kilometers, and cruising at a speed of 150 to 200 km per hour for a long time. The unmanned aerial vehicle will be used mostly for airborne early warning, aerial reconnaissance, disaster monitoring, meteorological observation and communications relay. [Photo/Xinhua]

However, solar drones like the CH UAV can perform well in this area and it is expected that such aircraft may be able to fly continuously for months or even longer in the future, said Li Guangjia, director of the project.

The CH UAV, with a wingspan of 45 meters equipped with solar panels, boasts a high cost efficiency as it does not require refuelling during long-term missions, said Shi Wen, chief engineer of the project.

Also, the solar-powered feature allows the UAV to generate no air pollution, making it environmentally-friendly, Shi said.