Utilizing the now well-developed science of rocketry, the modern exploration of space began in October 1957 when the Soviet Union launched Sputnik one. This tiny satellite orbited the earth for 57 days, providing information on radiation and other phenomena in the upper atmosphere. In less than a year, the United States had also launched a satellite, Explorer one. This started the "space race", years of competition between the U.S. and the U.S.S.R. to achieve new frontiers in space exploration. Space flight advanced rapidly from the simple sub-orbital flights of the 1950s, to manned missions to Earth's moon in the late 1960s. The rapid growth of space technology led to many practical applications, such as weather and surveillance satellites, and vastly improved worldwide communications. To