A locally-developed high-altitude solar-powered unmanned aerial vehicle (UAV) has successfully flown in the stratosphere. As a result, the development of a solar-powered UAV capable of remaining in the stratosphere for a long period of time will gain momentum.
On Aug. 11, the Korea Aerospace Research Institute (KARI) announced that its EAV-3, a high-altitude UAV powered by solar cells, succeeded in flying into the stratosphere with the altitude of 14 km above sea level.
This flight was conducted at an aviation center in South Jeolla Province. The EAV-3 reached 14.12 km above sea level during the 9-hour flight. At the altitude of 14 km, air density amounts to 53 percent of that contained at 10 km, a common altitude for civilian aircraft. Also, the temperature there is 30 degrees lower. The higher one goes, the lower air density and temperature fall, which makes flying difficult. On the other hand, the lack of clouds favors sunlight as an energy source.
EAV-3 is a 100 percent pollution-free aircraft that uses solar cells and secondary cells as energy sources in the stratosphere. A mono-crystal solar cell placed on the top of the wing continually charges a secondary cell during the flight, which is utilized as a source of energy. Wings are 20 m long and weigh only 53 kg. The KARI has created a safer UAV that flies at high altitude and can remain in the air for a long period of time through the development of the EAV-3. Specifically, the tech is expected to be usable in the design of an ultra-light stiff aircraft structure, the formation of aerial vehicles flying at high altitude, the design of propellers, the control of large UAVs flying at low speeds, and the operation of aerial vehicles for high altitude.
With its successful flight in the stratosphere, EAV-3 is likely to carry out more diverse tasks that complement artificial satellites, such as real-time close terrestrial observations and telecommunications relays.
The KARI has steadily improved the level of tech of UAVs capable of staying in the air at high altitudes for a long period of time. For example, it undertook the development of a core tech for electricity-powered UAVs in 2010, successfully flew a UAV for 22 hours in a row at 5 km in 2013, made its UAV reach the altitude of 10 km in 2014, and managed to fly its UAV for 25 consecutive hours. The research institute is going to embark on the development of a next-gen power source for the newly-developed UAV and a tech to produce ultra-light aerial vehicles, starting next year.
“We are planning to acquire tech for solar-powered UAVs capable of remaining in the air at high altitudes for a long period of time in order to carry out tasks like terrestrial observations, meteorological observations, and telecommunications relays, while remaining in the air for several weeks to months in the stratosphere,” said, Kim Seung-ho and Go Jung-ik, heads of the research team.