Verification of the Transient Behavior of the SLIM Propulsion System (Smart Lander for Investigating Moon)

SLIM (Smart Lander for Investigating Moon) is JAXA’s new lunar lander mission under development. The system firing test was conducted to acquire experimental data of transient behavior of propellant pressure in order to verify the requirement for the propulsion system design and the simulation model, using real propellants and the flight like model of SLIM propulsion system. We observed three remarkable phenomena, which are (1) wide frequency distribution in pressure fluctuation, (2) water hammer when the main engine’s valves are closed, and (3) cross talking. From the evaluation of test results and the combination with simulation, we understood the physical phenomena with real propellants and the flight like model. As a result, we concluded that the current design of SLIM propulsion system is compatible to all the requirements and the expected operational mode of SLIM.