16 January 2009

Artificial satellite

The invention Sputnik I, the first object put into orbit around the earth, which began the exploration of space. The people behind the invention Sergei P. Korolev (1907-1966), a Soviet rocket scientist Konstantin Tsiolkovsky (1857-1935), a Soviet schoolteacher and the founder of rocketry in the Soviet Union Robert H. Goddard (1882-1945), an American scientist and the founder of rocketry in the United States Wernher von Braun (1912-1977), a German who worked on rocket projects Arthur C. Clarke (1917- ), the author of more than fifty books and the visionary behind telecommunications satellites A Shocking Launch In Russian, sputnik means “satellite” or “fellow traveler.” On October4, 1957, Sputnik 1, the first artificial satellite to orbit Earth, wasplaced into successful orbit by the Soviet Union. The launch of this small aluminum sphere, 0.58 meter in diameter and weighing 83.6 kilograms, opened the doors to the frontiers of space. Orbiting Earth every 96 minutes, at 28,962 kilometers per hour, Sputnik 1 came within 215 kilometers of Earth at its closest point and 939 kilometers away at its farthest point. It carried equipment to measure the atmosphere and to experiment with the transmission of electromagnetic waves from space. Equipped with two radio transmitters (at different frequencies) that broadcast for twenty-one days, Sputnik 1 was in orbit for ninety-two days, until January 4, 1958, when it disintegrated in the atmosphere. Sputnik 1 was launched using a Soviet intercontinental ballistic missile (ICBM) modified by Soviet rocket expert Sergei P. Korolev. After the launch of Sputnik 2, less than a month later, Chester Bowles, a former United States ambassador to India and Nepal, wrote: “Armed with a nuclear warhead, the rocket which launched Sputnik 1 could destroy New York, Chicago, or Detroit 18 minutes after the button was pushed in Moscow.” Although the launch of Sputnik 1 came as a shock to the general public, it came as no surprise to those who followed rocketry. In June, 1957, the United States Air Force had issued a nonclassified memo stating that there was “every reason to believe that the Rus- sian satellite shot would be made on the hundredth anniversary” of Konstantin Tsiolkovsky’s birth. Thousands of Launches Rockets have been used since at least the twelfth century, when Europeans and the Chinese were using black powder devices. In 1659, the Polish engineer Kazimir Semenovich published his Roketten für Luft und Wasser (rockets for air and water), which had a drawing of a three-stage rocket. Rockets were used and perfected for warfare during the nineteenth and twentieth centuries. Nazi Germany’s V-2 rocket (thousands of which were launched by Germany against England during the closing years of World War II) was the model for American and Soviet rocket designers between 1945 and 1957. In the Soviet Union, Tsiolkovsky had been thinking about and writing about space flight since the last decade of the nineteenth century, and in the United States, Robert H. Goddard had been thinking about and experimenting with rockets since the first decade of the twentieth century. Wernher von Braun had worked on rocket projects for Nazi Germany duringWorldWar II, and, as the war was ending in May, 1945, von Braun and several hundred other people involved in German rocket projects surrendered to American troops in Europe. Hundreds of other German rocket experts ended up in the Soviet Union to continue with their research. Tom Bower pointed out in his book The Paperclip Conspiracy: The Hunt for the Nazi Scientists (1987)—so named because American “recruiting officers had identified [Nazi] scientists to be offered contracts by slipping an ordinary paperclip onto their files”—that American rocketry research was helped tremendously by Nazi scientists who switched sides after World War II. The successful launch of Sputnik 1 convinced people that space travel was no longer simply science fiction. The successful launch of Sputnik 2 on November 3, 1957, carrying the first space traveler, a dog named Laika (who was euthanized in orbit because there were no plans to retrieve her), showed that the launch of Sputnik 1 was only the beginning of greater things to come. Consequences After October 4, 1957, the Soviet Union and other nations launched more experimental satellites. On January 31, 1958, the United States sent up Explorer 1, after failing to launch a Vanguard satellite on December 6, 1957. Arthur C. Clarke, most famous for his many books of science fiction, published a technical paper in 1945 entitled “Extra-Terrestrial Relays: Can Rocket Stations GiveWorld-Wide Radio Coverage?” In that paper, he pointed out that a satellite placed in orbit at the correct height and speed above the equator would be able to hover over the same spot on Earth. The placement of three such “geostationary” satellites would allow radio signals to be transmitted around the world. By the 1990’s, communications satellites were numerous. In the first twenty-five years after Sputnik 1 was launched, from 1957 to 1982, more than two thousand objects were placed into various Earth orbits by more than twenty-four nations. On the average, something was launched into space every 3.82 days for this twentyfive- year period, all beginning with Sputnik 1.