Correct option is A
The correct answer is (a) Sputnik 1.
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Sputnik 1 was the first artificial satellite to be sent into space, launched by the Soviet Union on 4 October 1957.
· This historic event marked the beginning of the space age and the start of the space race between the United States and the Soviet Union.
· Sputnik 1 was a spherical satellite with four external radio antennas that broadcast radio pulses, allowing scientists to track its orbit.
· The satellite's successful launch demonstrated the feasibility of sending objects into space and provided valuable data on the density of the upper atmosphere and the propagation of radio signals in the ionosphere.
· Sputnik 1's launch had a significant impact on science, technology, and international politics, leading to increased investment and interest in space exploration.
Information Booster:
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Vanguard 1A: An American satellite, part of the Vanguard project, intended to be the first satellite in space but failed during launch in 1957. Vanguard 1, however, was successfully launched in 1958.
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Explorer 1: The first successful American satellite, launched on 31 January 1958, known for discovering the Van Allen radiation belts.
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Rohini: A series of Indian satellites, with the first one, Rohini 1, launched by the Indian Space Research Organisation (ISRO) in 1980.