[Edaily Reporter Kang Min-gu] #InnoSpace has completed the development of core technologies for the ‘LiMEK-04,’ a 0.4-ton-thrust liquid methane engine to be used in the kick stage of its next-generation launch vehicle, ‘HANBIT-Micro,’ and successfully conducted a 420-second long-duration ground combustion test.

The "dual-propellant regenerative-cooled methane engine combustion chamber technology" recently developed is the core technology of the 'LiMEK-04.' The kick stage is a space propulsion system that separates after the second-stage engine of the launch vehicle completes combustion, enabling the precise delivery of the payload to its target orbit.

This technology utilizes both propellants—liquid methane (fuel) and liquid oxygen (oxidizer)—as coolants to cool the combustion chamber in a methane engine. Regenerative cooling is a core technology that protects the engine from the ultra-high temperatures generated during combustion and maintains stable combustion, thereby influencing engine performance and launch vehicle efficiency.

Conventional methane engines have primarily employed a single-propellant regenerative cooling method that uses only liquid methane as a coolant. However, this method requires high propellant supply pressure to ensure sufficient cooling performance, which in turn necessitates more robust propellant tank and supply system designs, leading to increased weight.

In contrast, the dual-propellant regenerative cooling technology utilizes not only liquid methane but also liquid oxygen in the cooling process, increasing the coolant flow rate by approximately 3.0 to 3.4 times compared to conventional methods.

As a result, stable cooling performance can be maintained even under relatively low-pressure conditions, and the propellant tanks and supply systems can be made lighter, thereby reducing the overall weight of the launch vehicle and improving payload efficiency.

Kim Soo-jong, CEO of InnoSpace, stated, “As launch vehicles become smaller, weight sensitivity increases; therefore, in the small launch vehicle sector, structural lightweighting technology is a key factor that determines payload capacity and the competitiveness of launch services,” adding “This technology enables high cooling efficiency and weight reduction, so we expect it to be widely utilized not only in methane engines for future reusable launch vehicles but also in kick stages for small satellite orbital transport and space exploration propulsion systems,” he added.