The first artificial Earth satellite, Sputnik I , went into orbit on 4th October 1957 ,closely followed in the next month by Sputnik II. The first object to reach the moon from earth was the probe Lunik II in September 1959. In 1962 John Glenn orbited the Earth three times in the first Mercury craft to be boosted by an Atlas rocket ,and in June 1963 ,Valery Bykovsky set the five-day endurance record in space .The following year ,Alexei Leonove completed the first space walk .On July 20th 1969,Neil Armstrong became the first man to set foot on the Moon , the climax of an intensive American space programme. 视频：人类第一次登月During the next few years several manned and automatic probes were launched into space; on the Apollo（阿波罗） 15 mission, a lunar-roving vehicle collected a wide range of samples for analysis. Apollo 16 brought back over 91 kg of Moon rock and in December 1972, the last lunar landing was made by Apollo 17. We are now able to observe the celestial bodies（天体）with orbiting observatories that are sent out into space and relay astronomical information back to Earth: artificial satellites have been used for surveying; studying the electromagnetic and gravitational fields which surround the Earth; in communication when relaying television signals, and in meteorological observation.