moon33The Moon is Earth's only natural satellite.It orbits around Earth at an average distance of 384 399 km (238,854 mi; about 30 times Earth's diameter).The Moon rotates always facing Earth withKey Dates. July 1, 1966: Launch Jan. 1, 1967: Mission declared a success Sept. 15, 1971: Mission stops returning useful data In Depth: Explorer 33. It was hoped that Explorer