한국항공우주연구원

□ The Korea Aerospace Research Institute (KARI) disclosed on December 11 that it has developed a high-altitude electrical aerial vehicle (EAV-3) that can fly with solar power at high altitude where the atmosphere is thin, and successfully completed its operation in the stratosphere at an altitude of 14km.
○ KARI has been conducting flight tests of the EAV-3 at its Goheung Aeronautical Center in Jeonnam. The EAV-3 successfully reached a maximum altitude of 14.12km during a recent test flight lasting about 9 hours.
- At the altitude of 14km there is around 53% less air density and around 30℃ lower temperature (-60℃) then the altitude of 10km, which is the flight altitude of conventional commercial aircraft. Although air density and temperature rapidly decrease as the altitude increases, making it difficult to operate an air craft, it is the ideal environment for using solar power as an energy source as there is no cloud.

□ The EAV-3 is a 100% pollution-free electrical aerial vehicle that uses solar cells and secondary batteries (lithium ion) in order to remain at a high altitude in the stratosphere for an extended period of time.
○ The single-crystal solar cell installed on top of a wing continuously recharges the secondary battery that serves as the energy source. Although a wing span of around 20m is required to fly at high altitude where the air is thin, the EAV-3 is made with a cutting-edge Korean-made carbon fiber compound and weighs only 53kg.
○ The EAV-3 was designed, analyzed and systemized by KARI, with many small domestic companies participating in its fabrication and test flight. The participants included Sungwoo Engineering (fuselage fabrication and support of test flight), Tium Research (battery pack and control system fabrication), Soleitec (solar cell module fabrication), Ucon System (flight control computer and navigation system fabrication), and Smartec (motor fabrication).

□ The successful flight of the EAV-3 at an altitude of 14km is significant in that Korea is now a step closer to completing its development of high-altitude EAV development technology.
○ With the development of the EAV-3, KARI has secured various technologies including an ultralight, high strength fuselage structure, a high-altitude aircraft shape and propeller, control of low velocity UAV, a high-altitude low velocity-high torque motor, and operation of a high-altitude aircraft needed for the development of a complete high-altitude UAV.
○ As there is a jet stream of strong westerlies at 10km altitude above Korea in particular, advanced technologies are needed to enable a light aircraft to rise through the zone.

□ The UAV capable of operating in the high altitude of the stratosphere is an emerging technology that is being heavily developed by advanced countries to carry out various missions, such as precision ground observation and communication relay, in order to supplement satellites.
○ Zephyr by Qinetiq in the UK is the only solar powered EAV in the world that has succeeded in flying in the stratosphere for more than two weeks, while Helios, developed in the US, has succeeded in flying in the stratosphere for a short period.

□ KARI began developing the key technologies of the EAV in 2010 and has advanced the high-altitude long-endurance UAV by successfully flying it at an altitude of 5km for 22 hours straight in 2013, and at an altitude of 10km for 25 hours in 2014.
○ KARI plans to continue developing the high-altitude long-endurance solar cell powered EAV to operate in the stratosphere, which is inaccessible to conventional aircraft, for weeks and months to carry on such missions as ground observation (environmental and disaster monitoring, traffic monitoring and border monitoring), weather observation, and communication relay.

□ Following this research, the MSIP and KARI plan to begin the UAV Future Pioneering Technology Development Project in 2016, including the development of the next-generation energy source for a high-altitude long-endurance solar cell-powered EAV and ultralight aircraft technology.