[Mid-term Plan Key Point] ③ How to Densely Monitor North Korean Airspace

Current unmanned aerial vehicles have blind spots due to Earth's curvature and camera characteristics
Developing ultra-small military reconnaissance satellites to densely monitor North Korean airspace within an hour

[Asia Economy Yang Nak-gyu, Military Specialist Reporter] The Ministry of National Defense has decided to develop reconnaissance satellites that will closely monitor North Korean territory from North Korean airspace, including ultra-small reconnaissance satellites.

On the 10th, the Ministry of National Defense announced that it has established the 2021-2025 Defense Mid-term Plan, which includes plans for military force construction and operation over the next five years. The budget allocated in this mid-term defense plan is 300.7 trillion won, with 100.1 trillion won allocated to defense capability improvement to enhance advanced forces in preparation for all-around security threats, and 200.6 trillion won allocated for power operation costs for defense operations.

The military plans to operationalize military reconnaissance satellites by 2025 to improve the image capture cycle. The Global Hawk, which the South Korean military has already introduced, is an intelligence satellite-grade unmanned reconnaissance aircraft capable of identifying objects as small as 0.3m on the ground using special high-performance radar and infrared detection equipment at an altitude of 20 km. It can operate for 38 to 42 hours on a single flight. Its operational radius reaches 3,000 km, allowing surveillance beyond the Korean Peninsula.

The issue is the shooting time. The Global Hawk takes 60 seconds to capture one image. To capture about 2,500 images covering the entire North Korean territory, it takes more than 40 hours. Because of this, even with the introduction of the Global Hawk, it is expected that the military will have to rely on U.S. reconnaissance satellites for key North Korean military developments.

Another problem is the blind spots. Reconnaissance aircraft like the Global Hawk have blind spots due to the Earth's curvature and camera characteristics. U-2 reconnaissance aircraft and Global Hawk drones take photos of North Korean territory from an altitude of up to 20 km. If there is a 200m high mountain 100 km away, a blind spot of about 1 km behind the mountain where photos cannot be taken inevitably occurs. This is why the military is pushing for reconnaissance satellites.

Global Hawk takes 60 seconds to capture one image... Over 40 hours needed to photograph entire North Korean territory
Developing numerous small reconnaissance satellites, which are cheaper than large reconnaissance satellites, enables dense monitoring of North Korea

The military is currently promoting a project (Project 425) to introduce a total of five reconnaissance satellites with a budget of about 1.22 trillion won. They plan to introduce four satellites equipped with high-performance Synthetic Aperture Radar (SAR) and one satellite equipped with Electro-Optical (EO) and Infrared (IR) sensors. These satellites typically orbit at altitudes of 300 to 1,000 km, passing over North Korean airspace several times a day for surveillance. The reconnaissance cycle of these satellites is once every two hours, passing over North Korean airspace and taking photos. In two hours, North Korean missile mobile launchers can move about 40 to 60 km. This is why reconnaissance satellites alone are considered insufficient for monitoring North Korea.

Therefore, to monitor North Korea without any 24-hour gaps, small or ultra-small reconnaissance satellites, which are much cheaper and can be operated in much larger numbers than large reconnaissance satellites, are necessary. If 32 ultra-small SAR satellites being developed by the Agency for Defense Development (ADD) are launched, they can monitor the Korean Peninsula area at 30-minute intervals. This means that the movement of North Korea’s mobile launchers (TEL) that secretly launch missiles equipped with nuclear weapons can be detected in advance. The small satellites have the capability to observe objects as small as 1 meter at an altitude of 510 km. The production cost per unit is expected to be around 7 to 8 billion won. The military believes that since Hanwha Systems, a domestic defense company, has succeeded in developing AESA radar to be mounted on the Korean Fighter Experimental (KF-X), the development time and cost for SAR radar for ultra-small satellites can be significantly reduced.

The ultra-small satellite model differs from general satellites, which have a cylindrical main body with wing-shaped solar panels. It is a rectangular shape with an integrated design of a video radar on the front and solar panels on the back, reducing its size (3 m wide, 70 cm tall) and weight (66 kg). The ultra-small reconnaissance satellites developed in Korea may set a new world record. They surpass the performance of the currently most advanced ultra-small satellites. Until now, general reconnaissance satellites weighed between 500 kg and over 1 ton. Although the Finnish reconnaissance satellite has a resolution of about 1 meter, similar to the Korean satellite, it weighs about 85 kg, heavier than the Korean satellite. ADD began developing the ultra-small satellite in December last year and is currently in the preliminary design phase. The goal is to develop a ground test verification model by November 2023.