[Yang Nak-gyu's Defence Club] Three Uses of Solid Space Launch Vehicles

[Asia Economy Yang Nak-gyu, Military Specialist Reporter] Our military succeeded in the test launch of a solid-fuel space launch vehicle on the 30th, marking an achievement of "capturing three rabbits" in reconnaissance satellite, missile technology, and space exploration.

After the Korea-US missile guidelines were lifted in May last year, our military began developing solid-fuel propulsion launch vehicles. In July of the same year, the Agency for Defense Development (ADD) succeeded in the combustion test of a solid-fuel engine for space launch vehicles. Through this test launch, verification was conducted on engine combustion, fairing separation, stage separation, and upper stage attitude control technology. This means that a significant portion of the core technology of solid-fuel space launch vehicles has been verified.

The military is planning Project 425 using solid-fuel space launch vehicles. Using solid-fuel satellite launch vehicles, they plan to launch one optical reconnaissance satellite and four ultra-small synthetic aperture radar (SAR) reconnaissance satellites in 2025.

Our military also plans to launch an additional 32 ultra-small reconnaissance satellites. North Korea's liquid-fuel-based ballistic missiles have a launch preparation time of less than one hour, while solid-fuel-based ballistic missiles require only 20 to 30 minutes. Since Project 425 can reconnoiter North Korea at two-hour intervals with launched reconnaissance satellites alone, launching ultra-small reconnaissance satellites to perform missions simultaneously can enable dense reconnaissance of North Korean territory at intervals of 10 to 20 minutes. Strengthening our military's reconnaissance capability is expected to aid the transfer process of wartime operational control, as it is a key aspect of the transfer of operational control.

The ultra-small reconnaissance satellites disclosed by ADD measure 3 meters in width and 70 cm in height. They have a resolution of about 1 meter and weigh only 66 kg. However, regardless of day or night and adverse weather conditions, they can observe objects as small as 1 meter on the ground in high resolution from an orbit at an altitude of 510 km. Their lifespan is 2 to 3 years.

Missile development has also reached a certain level. The solid-fuel satellite launch vehicle was based on the Hyunmoo-4. Because of this, it is highly likely that domestic defense companies Hanwha and LIG Nex1, which participated in the Hyunmoo-4 project, will also participate in Project 425.

The solid-fuel satellite launch vehicle is known to have a thrust (75t) equivalent to that of one liquid engine of the Korean launch vehicle Nuri. It is evaluated to be at least an intermediate-range ballistic missile (IRBM) class with a range of about 3,000 to 5,500 km. Therefore, development of ballistic missiles at the level of or above the Hyunmoo-4 series is possible.

Following the end of the Korea-US missile guidelines, our military has steadily developed the Hyunmoo series missiles. Depending on the launch site, ground-launched surface-to-surface ballistic missiles are named 'Hyunmoo 4-1', ship-launched surface-to-surface ballistic missiles are 'Hyunmoo 4-2', and submarine-launched ballistic missiles (SLBM) are 'Hyunmoo 4-4'.

Hyunmoo 4-1 has a warhead weight of 2 tons, possessing at least three times the penetration power compared to the currently strongest GBU-57. It can penetrate more than 24 meters of reinforced concrete and 180 meters of general ground, effectively reaching tactical nuclear-level power. The Hyunmoo 4-2 missile is planned to be mounted on 30,000-ton class light aircraft carriers, and the Hyunmoo 4-4 missile on the 3,000-ton class submarine Dosan Ahn Changho.

In order to increase payload capacity of space launch vehicles in a short period and reduce launch costs, development of new types of space launch vehicle technology combining the advantages of solid and liquid fuel engines is expected to become possible. To this end, ADD and the Korea Aerospace Research Institute plan to accelerate mutual cooperation. The first stage propulsion will use a solid-fuel engine to improve management efficiency, while the second and third stages will be equipped with liquid engines for orbital insertion and other uses.

Hanwha Systems also announced on the 30th that it will participate in an asteroid exploration project that will approach Earth closely in seven years. Hanwha Systems is expected to participate in the asteroid Apophis exploration project together with the Korea Astronomy and Space Science Institute and the Korea Aerospace Research Institute.

The 370-meter-sized asteroid Apophis is expected to pass 31,600 km above Earth in April 2029, seven years from now. As Apophis, which retains the early appearance of the solar system, approaches Earth, it is expected to undergo changes such as an increase in orbital diameter and a tilt in its rotation axis due to gravitational influence. The goal of the Apophis exploration project is to observe these changes by launching a space probe developed with domestic technology using a domestic launch vehicle. If the Apophis exploration project proceeds as planned, the probe is expected to be launched around October 2027.