Illustration of an Apollo spacecraft during the translunar coast phase. The command and service module (CSM) is at left, the lunar module (LM), with its legs folded, is at right. This configuration was adopted by Apollo spacecrafts 11 to 17 between leaving Earth orbit and entering lunar orbit, a period of about 73 hours. Once in lunar orbit two astronauts transferred to the LM for separation and descent to the Moon.