Missile to the Moon (1958) Sub Indo

Two escaped convicts are found hiding in a rocketship built by a renegade inventor, who forces them to become the crew for a trip to the Moon. Also on board, as inadvertent stowaways, are his assistant and his secretary; and none of them are aware that the inventor is actually a Lunarian explorer sent to Earth by the dying Lunar civilization and the only remaining male member of that civilization.