Two proposals of manned lunar-landing propulsion system were discussed.The structure and basic parameters of propulsion system for existed 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

working reliability

a scheme of the first stage engine system for heavy lift launch vehicle was proposed.A heavy lift vehicle(HLV) system and a HLV series were estableshed

and their payload capability was calculated.Based on integrative analysis

the lunar launch vehicle is suggested to be 3 stage with 4 boosters

and two 50t liquid oxygen/liquid hydrogen are used for the third stage

while liquid oxygen/kerosene stage combustion cycle engines about 5000kN are used for all other stages.