ABriefHistorySpaceExploration.doc
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1、A Brief History: Space Exploration As often happens in science, the earliest practical work on rocket engines designed for spaceflight occurred simultaneously during the early 20th century in three countries by three key scientists: in Russia, by Konstantin Tsiolkovski; in the United States, by Robe
2、rt Goddard; and in Germany, by Hermann Oberth. In the 1930s and 1940s Nazi Germany saw the possibilities of using long-distance rockets as weapons. Late in World War II, London was attacked by 200-mile-range “V-2” missiles, which arched 60 miles high over the English Channel from Germany at more tha
3、n 3,500 miles per hour.After World War II, the United States and the Soviet Union created their own missile programs. On October 4, 1957, the Soviets launched the first artificial satellite, Sputnik 1, into space. Four years later on April 12, 1961, Russian Lt. Yuri Gagarin became the first human to
4、 orbit Earth in Vostok 1. His flight lasted 108 minutes, and Gagarin reached an altitude of 327 kilometers (about 202 miles). The first U.S. satellite, Explorer 1, went into orbit on January 31, 1958. In 1961 Alan Shepard became the first American to fly into space. On February 20, 1962, John Glenns
5、 historic flight made him the first American to orbit Earth.“Landing a man on the moon and returning him safely to Earth within a decade” was a national goal set by President John F. Kennedy in 1961. On July 20, 1969, Astronaut Neil Armstrong took “a giant step for mankind” as he stepped onto the mo
6、on. Six Apollo missions were made to explore the moon between 1969 and 1972.During the 1960s unmanned spacecraft photographed and probed the moon before astronauts ever landed. By the early 1970s orbiting communications and navigation satellites were in everyday use, and the Mariner spacecraft was o
7、rbiting and mapping the surface of Mars. By the end of the decade, the Voyager spacecraft had sent back detailed images of Jupiter and Saturn, their rings, and their moons.Skylab, Americas first space station, was a human-spaceflight highlight of the 1970s, as was the Apollo Soyuz Test Project, the
8、worlds first internationally crewed (American and Russian) space mission.In the 1980s satellite communications expanded to carry television programs, and people were able to pick up the satellite signals on their home dish antennas. Satellites discovered an ozone hole over Antarctica, pinpointed for
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