Space became another arena for competition after the Soviet Union launched Sputnik -- an artificial satellite -- in 1957. Americans were chastened, for the Russians had beaten them into orbit with a rocket that could have easily carried a nuclear bomb. The United States only managed to launch its first satellite, Explorer I, in 1958. The public mood worsened when the Soviets placed the first man in orbit in 1961. Kennedy responded by committing the United States to land a man on the moon and bring him back "before this decade is out."  

With Project Mercury, in August 1962 John H. Glenn Jr. became the first U.S. astronaut to orbit the Earth. In the mid-1960s, U.S. scientists used the Gemini program to examine the effects of prolonged space flight on man. Gemini, Latin for "twins," carried two astronauts, one more than the earlier Mercury series and one less than subsequent Apollo spacecraft. Gemini achieved several firsts, including an eight-day mission in August 1965 -- the longest space flight at that time -- and in November 1966, the first automatically controlled reentry into the Earth's atmosphere. Gemini also accomplished the first manned linkup of two spacecraft in flight as well as the first U.S. walks in space.  

The Apollo project achieved Kennedy's goal. In July 1969, with hundreds of millions of television viewers watching around the world, Neil A. Armstrong became the first human to walk on the surface of the moon.  

Other Apollo flights followed, but many Americans began to question the value of manned space flight. In the early 1970s, as other priorities became more pressing, the United States scaled down the space program. Some Apollo missions were scrapped; only one of two proposed Skylab space stations was built.