The Russians launched the world first artificial satellite,Sputnik I,on October 4,1957.Next,Sutnik2, carrying a dog called laika, went up into space on November 3. The Americans launched Explorer I, on January 31,1958. The Americans won the race to land on the moon more than ten years later-with Apollo 11 on July 20, 1969. "This is one small step for a man,one giant leap for mankind,"said astronaut Neil Armstrong,the first person to walk on the moon. Space exploration has continued since then, and has brought new discoveries in many different areas of science.