The gravitational force (pull) on moon is much less than on the pull on earth. Secondly. There was a returning to earth space capsule already orbiting the moon . The escaping velocity from the moon is way less than the escapinge velocity on earth. The returning capsule can also use earth's gravitational pull to help it reach escaping speed of the moon. All the way back from the moon to earth the space capsule need not used any nenergy for propulsion .earth's pull. Will allowed the capsule come back to earth. However, It may use some nenergy for correcting course.