Chinese Engine Plan Suggests Substantial Moon Base

by Bradley Perrett
Aerospace Daily & Defense Report

BEIJING—Chinese space propulsion engineers are working on an unusually powerful variable-thrust engine, suggesting correspondingly ambitious plans for the country’s proposed manned Moon base.

The engine would generate 80 kN (18,000 lb.) of thrust, compared with the 45 kN for the TRW Lunar Module Descent Engine used in the U.S. Apollo program.

The lander that used that U.S. engine, the Lunar Module, had a mass of 15 metric tons.

The proposed Chinese variable-thrust engine was outlined by the Xian Aerospace Propulsion Institute, part of leading Chinese space program supplier CASC, at the Global Space Exploration Conference held in Beijing on June 6-8.

Propellants would be liquid oxygen and a hydrocarbon, such as kerosene. Deep throttling, down to only 10% of maximum thrust, could be achieved in part by using two manifolds for propellant supply, shutting down one as necessary, according to the concept described to the conference by the institute’s Li Ping.

Such an engine should be developed for Chinese space exploration, Li said, suggesting that funds are not yet allocated for the program. Still, Li’s thrust target presumably meets a preliminary requirement from lunar program designers that is based on the mass that they want to land.

An engine with a wide thrust range is needed for precise control in landings on astronomical bodies. The institute’s engine is proposed for landing on Mars as well as the Moon.

Chinese space program managers notably refer to the manned object that they hope to place on the Moon not as a lander or a landing module but as a base, implying prolonged presence and therefore considerable size.

Further, their proposed Long March 9 Moon rocket would be powerful enough to send an object rather larger than the U.S. Lunar Module to the Moon’s surface. Long March 9 studies envisage translunar injection mass—the weight hurled to the Moon—of 50 metric tons, compared with the combined 44 metric tons of Apollo’s Lunar Module and Command and Service Modules.

Engineers are working on key technologies for manned Moon missions proposed for 2031–36. The full-scale program has not been approved, however.

The series of six unmanned probes that China began sending to the Moon in 2007 use a 7.5 kN variable-thrust engine that burns unsymmetrical dimethylhydrazine with nitrogen tetroxide.

One was installed on each of the Chang’e 1, 2 and 3 probes and will be on Chang’e 4, due for launch next year. Chang’e 5 and 6, which will be larger, will have two of the engines. Chang’e 5 is due to be launched this year.