The structure and basic parameters of propulsion system for existing heavy lift launch vehicles were analyzed.The structure and task requirements were proposed to meet the manned lunar-landing demand.Considering the performance

economics

technical difficulties and working reliability

a scheme of the first stage engine system for heavy lift launch vehicle was proposed

including the thrust level

propellant type and engine cycle.System simulation models were established for 9 model engines using the object-oriented sequential analysis method

and the maximum chamber pressures and balanced system parameters were computed.The influence of chamber pressure and mixture ratio on the engine performance was analyzed.Based on integrative analysis

4 500～5 000 kN liquid oxygen/ kerosene engine system of stage combustion cycle with oxygen-rich preburner is preferred.