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| Introduction |
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| In the second century AD a Greek writer named Lucian wrote a story about a trip to the moon. He did not even know how far the moon was but his story revealed that the idea of space travel was certainly not new. |
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| Much later in 1865, the French novelist Jules Verne wrote a story in which his travelers were fired from the earth to the moon in a hollow globe shot out of the barrel of a big gun. He was careful to give the correct speed, 11.2 km/s which is the escape velocity of earth. |
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| Can't we use aircrafts to reach the moon? No. This is because they cannot fly unless there is air around them and there is not much air higher than a few kilometers above the earth's surface. The problem was solved when the first rocket was invented. |
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| In 1926, an American rocket engineer Robert Goddard, built and tested the first rocket which used liquid fuels instead of solid gun powder. During the Second World War powerful liquid fuel rockets were built by Germans to carry explosives. Later, Americans started building their own rockets not to carry explosives but to launch artificial satellites. |
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| In 1957, the Russians successfully launched the first satellite Sputnik-I, (the size of a football) carrying a radio transmitter. The first American satellite Explorer-I followed in the subsequent year and in 1961, Vostok-I the first manned space flight by the Russian cosmonaut Yuri Gagarin was launched. Since then thousands of satellites have been launched and many manned flights have been made. The first true space station was launched in the 1970's. Artificial satellites may often be seen looking like stars moving slowly across the sky. |
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