December 30, 2013
Credit: China Space News
Among the challenges Chinese engineers had to overcome in achieving a landing on the Moon, one of the trickiest was developing a powerful variable-thrust engine for the job—one that could responsively throttle up and down as needed to get the probe to lunar orbit, then deliver it to its landing point, stopping on the way to survey the terrain.
Chinese development engineers overcame many roadblocks to bring the engine to fruition. It is the main powerplant for the Chang'e 3 lunar probe, says the chief designer for the propulsion program, Jin Guangming. Generating 7.5 kilonewtons (1,690 lb.) of thrust, it is three times as powerful as the main powerplant of China's Shenzhou manned spacecraft, Jin says, emphasizing that the main difficulty in development was not the large increase in output but, rather, achieving a wide range of variable thrust, precision control, high performance (presumably meaning efficiency) and durability.