[Exclusive] 'Like SpaceX'... Securing Advanced Rocket Technology to Follow Nuriho

KARI Successfully Validates Reignition Technology with Recent 9t-Class Engine Prototype
Enabling Rocket Reusability and Efficient Utilization, Dramatically Improving Cost-Effectiveness

The Korea Aerospace Research Institute (KARI) recently developed a 9-ton class liquid engine applying engine reignition and staged combustion cycle technologies and successfully completed test operations. Photo by KARI YouTube channel capture.

[Asia Economy Reporter Kim Bong-su] South Korea has succeeded in developing a 'reusable' engine, which is the global trend in the space rocket market. This achievement is evaluated as securing the core technology to overcome the limitations of the first Korean space launch vehicle 'Nuriho,' which is 'single-use,' and to compete with advanced rockets such as the United States' SpaceX.

The Korea Aerospace Research Institute (KARI, hereinafter referred to as KARI) announced on the 24th that it has succeeded in the reignition combustion test of a 9-ton class engine verification prototype developed to secure key technologies for multiple satellite launches and launch vehicle reuse.

KARI has been researching engine reignition technology since 2016, and for the first time, it produced a verification prototype and successfully completed an experiment in which the engine was operated for 320 seconds, then turned off, and reignited after 370 seconds. The previously developed 7-ton and 75-ton engines used in the Nuriho launch on the 21st of last month could only be ignited once, making efficient utilization, various mission executions, and reuse fundamentally impossible. Additionally, the 9-ton engine tested this time applied a more advanced technology called the staged combustion cycle. This method, like a 'reverse-burning boiler,' spins the turbine and then reintroduces the exhaust gas back into the combustion chamber for burning. Compared to the existing 7-ton and 75-ton engines that use an open cycle gas generator method, which immediately expels the gas that spins the turbine, the staged combustion cycle method improves fuel efficiency by more than 5-7%.

KARI plans to utilize these technologies for improving the performance of Nuriho and developing next-generation launch vehicles. Enabling engine reignition will dramatically improve the performance of launch vehicles and secure economic feasibility. By turning the engine off and on, it becomes possible to perform missions in multiple orbits from a single launch. Using less fuel also increases satellite deployment capacity.

Above all, this is a core technology for rocket reuse. Currently, SpaceX's Falcon 9 rocket and Blue Origin's space tourism rocket 'New Shepard' adopt methods that use engine reignition and thrust control technologies to change direction and reduce landing speed after mission completion. This allows space launch vehicles to be reused multiple times, reducing the cost per launch to at least around 20 million dollars.

Han Young-min, head of the Launch Vehicle Engine Development Department at KARI, said, "With the success of this experiment, we believe that about half of the technology research required to secure reignition engine technology has been achieved," adding, "We plan to develop engines capable of not only reignition but also thrust control and apply them to the Nuriho advancement project scheduled to proceed after next year."