[Reading Science] Can the Nuriho, with Many 'Sagong', Really Go to the Moon?

Performance Improvement R&D Budget of 1.5 Trillion Won Excluded from Next Year's Budget Plan
Chronic Limitations of Korean Space Policy Revealed...Long-term Investment and Private Sector Autonomy Needed
Controversy Over Improvement R&D Technology Targets

On the 1st, the completed certification model of Korea's first space launch vehicle, 'Nuriho,' was unveiled for the first time and erected on the launch pad at Naro Space Center in Oenaro-do, Goheung-gun, Jeollanam-do. The completed Nuriho is being transported to the launch pad. Photo by Korea Aerospace Research Institute (KARI)

[Asia Economy Reporter Kim Bong-su] The first Korean-type space launch vehicle, Nuriho, with many stakeholders, can it really go to the moon? It has been confirmed that the government has completely cut the budget for the research and development (R&D) project to improve the performance of Nuriho, the first Korean independent launch vehicle, in next year's budget proposal, sparking an aftershock. In the rapidly unfolding New Space era, a long year will be wasted. There is strong criticism that this is a case revealing the chronic problems of Korea's 'top-down' and 'non-expert' space policy decisions.

◆ R&D personnel left idle

Recently, while drafting next year's national R&D budget of about 23.5 trillion won, the government completely cut the R&D budget of about 1.5 trillion won for the performance enhancement of Nuriho. As a result, R&D personnel and equipment who have participated in the development of major parts such as Nuriho's engine, fuel tank, fairing (cargo bay), and launch pad are in danger of practically suspending their work. Although the government has preserved the budget for the additional production of four units for repeated launches, allowing basic operating expenses and personnel costs to be maintained, it is inevitable to stop technology development. Since engine development was already completed one to two years ago, over 300 top-level R&D personnel belonging to companies related to Nuriho will have to spend the next several years doing only paperwork.

Nuriho is the first independent launch vehicle developed solely with domestic technology. Without foreign technical support, it independently developed a 75-ton liquid fuel (kerosene) engine, becoming the seventh in the world to do so, and also designed and manufactured the 2-3mm thick main body (fuel tank) and fairing on its own. Employees of the Korea Aerospace Research Institute (KARI) had to stay up all night pondering several difficult problems. During the development of the engine that burns 100 liters of fuel per second, combustion instability issues arose, leading to a 16-month struggle. To make large fuel tanks with diameters of 2.6m and 3.5m that can withstand high pressure using 2mm-thick special aluminum alloy plates, they developed plasma welding technology and went through numerous trials and errors.

Nevertheless, the performance and technical limitations are clear. Nuriho consists of a first stage 47.2m long with four 75-ton engines combined, a single second stage, and a 7-ton third stage, but its thrust is weak, so it cannot carry heavy payloads to high orbits. It can only place a 1.5-ton satellite into a low Earth orbit of 500-600km altitude. Compared to competing countries' space launch vehicles such as France's Ariane 5 (9.6 tons), the United States' Atlas V (8.1 tons), SpaceX's Falcon 9 (23 tons to low Earth orbit), and Russia's Soyuz 2.1a (4.8 tons to sun-synchronous orbit), there is still a long way to go.

After President Moon Jae-in observed the comprehensive combustion test of Nuriho's first stage at the Naro Space Center last March and pledged to launch a lunar lander by 2030 using an independent launch vehicle, the performance improvement work seemed to gain momentum. This is essential to send a lunar lander weighing several hundred kilograms from Earth to the moon, 300,000 km away. The fuel used is kerosene, which emits many pollutants and is unfavorable for engine reuse, and the combustion method is an open gas generator cycle developed by the former Soviet Union in the 1950s, resulting in low efficiency and pressure, making it difficult to generate high thrust. KARI is already developing an engine with a closed multi-stage combustion cycle that has higher fuel efficiency and pressure.

◆ Chronic problems in space policy worsen

The fact that the Nuriho upgrade R&D project has been practically halted is pointed out as another example of Korea's unique chronic problems in space development policy. Currently, Korea's space development projects are overall conducted as national R&D projects funded solely by government budgets. Therefore, they must secure budgets through preliminary feasibility studies. The problem is that this method no longer allows for flexible and agile investments suited to the rapidly expanding private space industry era, nor for long-term visionary investments to develop leading technologies. Due to the nature of the preliminary feasibility study system, the characteristics of R&D requiring long-term and stable investment are often ignored.

In particular, Korea's past space development policies have continued a stepwise project approach where the next stage's plan and budget are set only after the success of a single project, without continuity or long-term planning. A representative example is the Naroho, developed before Nuriho, which experienced three failures and caused the entire long-term space development program to be practically suspended. Overseas, regardless of the failure of specific projects, sectoral R&D continues steadily, and private entities are entrusted with entire projects to proceed autonomously. There is a call for Korea to shift to this approach. Professor Heo Hwan-il of Chungnam National University said, "Even if large projects are conducted to meet the expectations of the public and experts, core technologies such as engine development should be supported to conduct steady preliminary R&D as general projects without undergoing preliminary feasibility studies." He added, "If such situations are left unattended, it will cause significant damage to Korea's space development R&D, including talent outflow and decline in technological levels."

There are also many voices urging urgent improvement in the non-expertise of space policy decisions. Although the government is upgrading the National Space Committee under the Prime Minister and establishing a Space Policy Center under the Science and Technology Policy Institute to improve the system, frontline experts advise building a system with a certain degree of independence and expertise, such as a space agency or an independent National Space Committee like NASA in the United States, to lead overall policy.

◆ Quantum jump vs ignoring reality

Behind the budget cut for Nuriho upgrade R&D lies controversy over technical targets. In this preliminary feasibility study, the Ministry of Science and ICT and KARI submitted plans to partially improve Nuriho's performance to achieve a maximum altitude of over 700 km and a payload capacity of over 2.8 tons. Some preliminary feasibility study review committee members reportedly pointed out the need for a 'quantum jump'?a great leap forward. They argue that even if somewhat challenging, this upgrade project should achieve technological progress to catch up with advanced countries like the United States. Many experts share this view. They say that the technology level of Nuriho, similar to that developed by the former Soviet Union in the 1950s, should be innovated to catch up with the cutting-edge level of American private companies like SpaceX. Tasks include developing reusable liquid methane engines, acquiring engine thrust control technology, installing advanced sensors and control computers, and introducing multi-stage combustion cycles. Former KARI Director Kim Seung-jo recently wrote, "Science can produce research results that surpass limits even with low goals, but in technology development, once the goal is set low, it never produces better performance," urging 'disruptive innovation' without fear of failure.

Space rockets launched from Korea.

However, in the research field, there is criticism that this is "armchair theorizing that ignores reality." For example, liquid methane engines are unstable fuels; SpaceX's 'Starship' under development has exploded 11 times due to fuel leaks and other issues, and no commercialized liquid methane engines exist yet. Liquid methane itself is not commercially used as fuel in Korea, making it difficult to even obtain for engines. Advanced space launch vehicles under development in countries such as France's Ariane 6 and Japan's H3 are also continuously failing or, even if completed, have costs far exceeding targets, making it difficult to catch up with SpaceX's 'old' Falcon 9 currently in operation.

An official from a research institute said, "Space launch vehicles should be developed and operated efficiently according to the country's industrial base and circumstances, deciding development directions accordingly." He added, "Even the United States, which has been developing space launch vehicles for over 50 years and has a solid private industrial base, repeatedly fails while developing advanced rockets. It's like suddenly being asked to produce a top-grade Genesis when you can barely make a Pony."