Sputnik, the first artificial satellite, opened the space era and sparked competition between the Soviet Union and the United States. In 1948 a group of Soviet military scientists under a prominent space pioneer, Mikhail Tikhonravov, began early studies of artificial satellites. In August 1954 the government approved its leading missile design organization, OKB-1 (Experimental Design Bureau), led by Sergei Korolev, to begin preliminary research on satellites and launch vehicles based on the R-7 ballistic missile. On 30 January 1956 another government decree authorized the development of a scientific satellite, Object D, to be launched in response to the U.S. Vanguard satellite program during the International Geophysical Year (July 1957–December 1958). Tikhonravov initially participated in the satellite project as a consultant and later as a head of the newly established spacecraft development department.
Object D was an ambitious and complex design: it contained 12 different sensor systems to measure solar radiation, ionosphere particles, and detect micrometeorites. The project quickly ran into unexpected impediments, and its mission was delayed until April 1958. Thus, in February 1957, OKB-1 obtained government authorization to launch a simpler satellite first.
That new project, originally designated Primitive Satellite (PS), became the first Sputnik and made history as the world's first artificial satellite after its successful launch on 4 October 1957. It consisted of a sealed aluminum sphere, 580 mm in diameter and 83.6 kg in mass, containing a radio transmitter, temperature control system, and batteries. Two pairs of antennae, 2.4 m and 2.9 m long, were attached to the surface of the satellite. Sputnik was launched to a 947 km × 228 km orbit by a two-stage R-7 missile prototype and remained active for three weeks. It reentered on 4 January 1958.
Realizing the important propaganda effect of the first Sputnik, the Soviet authorities urged OKB-1 to repeat the feat quickly. Hastily constructed of available components, yet intended to be more spectacular, Sputnik 2 (PS 2) consisted of three containers with a compound mass of 508.3 kg, positioned in a conical frame permanently attached to the second stage of the booster rocket. The prime project task was to sustain a dog, Laika, for seven days in space and transmit her vital parameters to Earth. PS 2 was equipped with radiation sensors. Although successfully orbited on 3 November 1957, Sputnik 2 did not achieve its prime objective: Laika died soon after launch due to overheating caused by failed aerodynamic shroud separation. Sputnik 2 detected radiation belts around Earth, but Soviet scientists did not immediately publish their finding, losing the discovery to the first U.S. satellite, Explorer 1, and James Van Allen.
The launch of Object D, on 27 April 1958, ended in a booster failure. The reserved satellite sample, now designated Sputnik 3, went into space on 15 May 1958. The conical satellite was 3.57 m long and 1.73 m in diameter with an orbital mass of 1,327 kg including 968 kg of scientific equipment. Sputnik 3 was the first satellite powered by solar batteries. Unlike the previous Sputniks, that one was launched by a dedicated version of the R-7 missile. Sputnik 3 confirmed the existence of Earth's radiation belts and determined their borders, but much of the satellite's scientific data was lost due to a failed recording device.
See also: Effect of Sputnik; Korolev, Sergei; Russian Space Launch Centers
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