[Military Story] You Can See the Korean Peninsula Satellite at a Glance Here

Hanwha Systems Space Object Laser Observation Support Facility Tour
Observing All Korean Peninsula Satellites with a 5m High Large Telescope

North Korea launched its second military reconnaissance satellite in May last year. The satellite exploded during flight, resulting in a failed launch. The launch of the second satellite came about six months after the first military reconnaissance satellite was launched on November 21 of the previous year. Although the launch of the military reconnaissance satellite Malligyeong 1 was successful, it has not fulfilled its intended role as a satellite. North Korea declared last year that it would launch three more military reconnaissance satellites. In response, our military plans to establish a satellite monitoring system. This system will be able to monitor satellites orbiting over the Korean Peninsula launched by various countries, including North Korea. The Space Object Laser Observation Support Facility located in Geochang-gun, Gyeongsangnam-do, serves this purpose.

Space Object Laser Observation Support Facility located in Geochang-gun, Gyeongsangnam-do (Photo by Defense Rapid Acquisition Technology Research Institute)

The large telescope weighs 4 tons. This telescope completes one rotation every 12 seconds. The satellite flies at a speed of 8 km per second, and the telescope matches this speed to track it. (Photo by Defense Rapid Acquisition Technology Institute)

The mountain path of Gamaksan, at an altitude of 900 meters, was rugged. The uphill slope was at least 25 degrees. Even regular vehicles struggled to climb. Upon reaching the summit, it was clear that this was the closest point to the sky. It was surrounded by nearby mountains such as Machasan (588m), Jungseongsan (150m), and Namsan (211m). Inside the dome-shaped building, advanced equipment and various servers filled the space. Air conditioning was running at full capacity to cool the heat emitted by the equipment.

An official from the Defense Rapid Acquisition Technology Research Institute said, "Observation is impossible in urban areas due to light pollution such as neon signs," adding, "This is why the U.S. installed an observatory at Mauna Kea in Hawaii at an altitude of 4,200 meters."

Satellite Observation by Orbital Altitude

This facility observes artificial satellites orbiting the Earth. Artificial satellites are classified by orbital altitude into low Earth orbit (altitude 200?2,000 km), medium Earth orbit (2,000?36,000 km), geostationary orbit (36,000 km), and high Earth orbit satellites. Earth observation satellites and reconnaissance satellites orbit in low Earth orbit, while navigation satellites for satellite navigation systems like GPS orbit in medium Earth orbit. Geostationary orbit is mainly occupied by communication and weather satellites covering wide areas. Because they orbit the Earth at the same speed as the Earth's rotation, they appear stationary over one spot. High Earth orbit satellites are used for space exploration.

A Hanwha Systems official guided us to the second floor to show a telescope capable of viewing satellites. Beneath a 9-meter diameter dome was a large telescope standing 5 meters tall. The telescope alone weighs 4 tons. It completes one orbit around the Earth every 12 seconds. Since satellites fly at speeds of 8 km per second, the telescope must match this speed to track them. When the telescope was powered on, it began operating with a 'beep' sound while rotating 360 degrees.

The Hanwha Systems official explained, "Objects twinkling and moving in the night sky are airplanes, while objects shining like stars and moving quickly are satellites," adding, "Over 1,000 satellites orbit above the Korean Peninsula daily, and we can track all of them."

Telescope Diameter of 1.5m... Largest in Korea

The telescope has a diameter of 1.5 meters, making it the largest telescope developed with domestic technology. It tracks satellites by firing lasers through the telescope and analyzing the returning signals. The larger the telescope, the smaller the objects it can observe. It can also track geostationary satellites. Satellites can be detected by radar and imaging. Radar covers a wide area but has a high margin of error. Imaging is difficult under cloudy weather conditions. Satellites launched by most countries are registered with the Union of Concerned Scientists (UCS), a nonprofit organization. The problem lies with military satellites, which orbit the Earth secretly. Our military plans to establish a high-power laser satellite tracking system by 2030 to track all military satellites orbiting above the Korean Peninsula.

The telescope at the Space Object Laser Observation Support Facility moves at the same speed as the object being tracked. To track a geostationary satellite, the telescope moves at the Earth's rotational speed because geostationary orbit matches the Earth's rotation. When tracking satellites moving at speeds of 8 km per second, the telescope moves at that speed, which translates to 10 degrees per second. When tracking in this way, fixed objects like stars appear as single points, while fast-moving objects like artificial satellites appear as line segments along their trajectories. Artificial satellites orbiting in polar orbits rather than equatorial orbits show these line segments vertically. By integrating information from Korea and the U.S., it is possible to determine whether an object is a satellite, and if so, whether it is for civilian or military use.

Advanced Technology for Tracking Satellites Without Reflectors

We moved to the laser firing room located on the first floor. It was necessary to wear white gowns and tinted glasses, much like in a semiconductor factory. To deliver the laser to the telescope on the second floor, the beam must pass through a type of mirror. The higher the laser output, the more advanced the technology required for this mirror. When tracking satellites, reflectors on the satellites allow tracking at lower output. However, when tracking space objects without reflectors, high output is necessary. Dust particles can cause the laser firing angle to deviate. Even a one-degree deviation can cause errors of tens of kilometers in space, resulting in critical errors. Since lasers emit strong light, tinted glasses are essential to protect the eyes.

Son Eui-seung, team leader at the Defense Rapid Acquisition Technology Research Institute, said, "We plan to complete performance tests using the Space Object Laser Observation Support Facility by this year and secure core technologies necessary for developing a high-power laser satellite tracking system," adding, "Once our military establishes this system, it will be possible to predict not only military satellites but also defunct satellites that could fall at any time in advance."