From earliest times man have dreamed of traveling in space, exploring new worlds, reaching for the stars – an apparently impossible dream. Then rocket research which took place during World War II gave a great impetus to space travel for which rocket propulsion is essential. After many experiments the first major break-through came in April 1961 when a Russian, Yuri Gagarin, spent 108 breath-taking minutes in space. Three weeks later Commander Alan Shephard of the U.S. Navy also journeyed into outer space. The greatest milestone so far passed was in July 1969 when two more Americans, Neil Armstrong and Edwin J. Aldrin Jr. stepped on to the moon.