When China started to get serious about sending its astronauts to the Moon in the middle of the last decade, the country's senior rocket scientists began to plan a large booster to do the job. In 2016 the country's state-owned rocket developer, the China Academy of Launch Vehicle Technology, began designing the "Long March 9" rocket. It looked more or less like the large heavy lifter NASA was designing at the time, the Space Launch System. Like NASA's large rocket, the Long March 9 had a core stage and boosters and was intended to be fully expendable. There were some...