Korean Solar-Powered UAV Flies for 170 Hours... KRW 1 Trillion Challenge to Develop Future Aircraft

EAV-4 More Than Triples Domestic Record... Reaches 21.2 km, Demonstrates Wildfire Detection
Mission Demonstrations Through 2030... Hybrid VTOL Aircraft Development Set to Begin in 2028

A stratospheric solar-powered unmanned aerial vehicle developed using domestic technology has successfully flown continuously for 170 hours. The achievement is more than three times the previous domestic record, and the aircraft demonstrated its ability to detect wildfires while flying for a week at an altitude of more than 20 km in the stratosphere. The government plans to accelerate the commercialization of long-endurance UAVs based on this achievement, while also pursuing development of a hybrid vertical takeoff and landing aircraft with a budget of more than KRW 1 trillion.

The Korea Aerospace Administration (KASA) held a press briefing in Gwanghwamun, Seoul, on November 11 and announced the results of the long-endurance flight test of the stratospheric solar-powered UAV EAV-4, along with plans to develop future aircraft.

The stratospheric solar-powered unmanned aerial vehicle (EAV-4) takes off. Provided by the Korea Aerospace Administration (KASA).

The EAV-4, developed by the Korea Aerospace Research Institute, flew without landing for 170 hours and 5 minutes from August 18 to 25. This is more than three times the previous domestic record of 53 hours, set by the EAV-3 in 2020. Its maximum flight altitude was 21.2 km. KASA said the achievement ranks second in the world for long-endurance flight, behind Europe's Airbus Zephyr.

The EAV-4 is a UAV with a wingspan of 36 m, a fuselage length of 16 m, and a maximum weight of 150 kg. It generates electricity with solar cells during the day to charge its batteries, then flies at night using the stored power. It is designed to carry mission equipment weighing up to 20 kg.

The test also confirmed the aircraft's potential for wildfire detection. The Korea Aerospace Research Institute created a simulated wildfire near its flight test site and detected the ignition point from an altitude of about 14 km using electro-optical and infrared cameras. The infrared imagery identified an early-stage fire that would be difficult to spot with a regular camera, demonstrating the aircraft's potential as a disaster-monitoring platform.

Stratospheric solar-powered UAVs can observe specific areas for extended periods from an altitude closer to the ground than satellites. They can be used for wildfire and maritime surveillance, restoring disaster communications networks, and relaying communications to islands and mountainous areas. Unlike satellites, they can also be recovered on the ground for maintenance or to replace mission equipment.

The stratospheric solar-powered drone (EAV-4) flies through the stratosphere. Photo courtesy of the Korea Aerospace Administration (KASA).

However, challenges remain before the technology can be commercialized. In South Korea, reduced solar power generation during winter, strong jet streams, and limited test airspace pose obstacles to long-endurance flights. The seven-day flight test was also ended after taking into account the possibility of the aircraft leaving its designated airspace due to strong winds.

KASA said that analysis of the flight data confirmed the technical possibility of keeping the aircraft aloft for more than 30 days. However, an actual continuous 30-day flight has not yet been verified.

KASA plans to expand mission demonstrations led by private companies. It has completed evaluations of proposals from companies seeking to carry out the follow-up project and is negotiating agreements. It plans to build three additional UAVs for use in communications relay, disaster monitoring, and validation of domestically produced solar cells.

"Unlike satellites, stratospheric UAVs can be recovered on the ground for maintenance or to replace mission equipment," said Han Changheon, head of the Aviation Innovation Division at KASA. "The challenge is to demonstrate whether they can be used for a range of public and commercial missions and turn that into business opportunities."

Hybrid VTOL Aircraft Development to Move Forward with a Budget of More Than KRW 1 Trillion

KASA is also pursuing development of a hybrid vertical takeoff and landing aircraft that can take off and land without a runway. It plans to invest a total project budget of KRW 1.0861 trillion from 2028 to 2032 and secure four prototypes. The project budget and schedule will be finalized after government review.

The goal is to develop an aircraft in the five-seat class, including the pilot, with a range of at least 200 km and a payload capacity of at least 600 kg. Unlike electric vertical takeoff and landing aircraft (eVTOLs) that rely solely on batteries, this aircraft will also use electricity generated by an engine to increase its range and carrying capacity.

The hybrid vertical takeoff and landing aircraft (OPPAV) is landing after completing its flight. Photo provided by the Korea Aerospace Administration.

The key component is a 1-megawatt (MW) hybrid propulsion system. KASA is considering a turbogenerator combining a turbine engine and a generator as the leading option for power generation.

Asked how the aircraft would differ from competing models overseas, Han said, "The future aircraft market is still at a stage where commercial demand has not been established." He explained that the target was set at four to five seats and a payload of 500 to 600 kg, taking into account travel by families.

He added, "Current battery technology alone has limits when it comes to extending flight range, so a hybrid approach that also generates power through an engine is a practical alternative."

Han Changheon, head of the Aviation Innovation Division at the Korea Aerospace Administration (KASA), answers reporters' questions. Provided by KASA.

On the possibility of localizing production of the key 1 MW propulsion system, Han said that related preliminary research and development projects had already begun. KASA plans to secure core propulsion technologies by linking the turbogenerator development project with the future aircraft development project.

Securing the budget will be critical to moving the project forward. Asked about the likelihood of approval for a project worth more than KRW 1 trillion and concerns about schedule delays, Han stressed the need to secure an independent platform to foster the civil aviation industry. He explained that securing a future aircraft platform and using it to foster related industries as well would be an efficient way to develop the civil aviation industry.

KASA aims to obtain project approval by September 2027 and include initial costs in the 2028 budget. The aircraft, once developed, is planned for use in emergency logistics to islands and mountainous areas, medical evacuations, and regional air transport.

"Developing the domestic civil aviation industry requires securing an independent aircraft platform," Han said. "We believe that developing future aircraft and fostering related materials and components industries at the same time is the most efficient approach."

This content was produced with the assistance of AI translation services.