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Sputnik 1

2007 Schools Wikipedia Selection. Related subjects: Space transport

                     Sputnik 1
   Sputnik 1
     Organization:            Soviet Union
   Major Contractors:    Korolev Design Bureau
     Mission type:           Earth Science
     Satellite of:               Earth
      Launch Date:    October 4, 1957 at 19:12 UTC
    Launch Vehicle:          R-7/SS-6 ICBM
         Decay:             January 4, 1958
   Mission Duration:            3 weeks
       NSSDC ID:               1957-001B
        Webpage:       NASA NSSDC Master Catalog
         Mass:                  83.6 kg
    Semimajor Axis:            6,955.2 km
     Eccentricity:               .05201
      Inclination:               65.1°
    Orbital Period:           96.2 minutes
       Apoapsis:                 939 km
       Periapsis:                215 km
        Orbits:                  ~1,400

   Sputnik 1 (Russian: Спутник-1, Satellite 1) was the first artificial
   satellite to be put into orbit, on October 4, 1957. Coming at the
   height of the Cold War, the launching of Sputnik caught the West by
   surprise, and in the U.S. led to a wave of self-recriminations, the
   beginning of the space race, and a movement to reform science
   education.

Spacecraft design

   The satellite weighed about 83 kg (184 pounds). The Sputnik 1 satellite
   was a 58.0 cm-diameter aluminium sphere that carried four whip-like
   antennas that were 2.4-2.9 m long. The antennas looked like long
   "whiskers" pointing to one side. It had two radio transmitters (20 and
   40 MHz) and is believed to have orbited Earth at a height of about 250
   km (150 miles). Analysis of the radio signals was used to gather
   information about the electron density of the ionosphere. Temperature
   and pressure were encoded in the duration of radio beeps, indicating
   the satellite was not punctured by a meteorite. Sputnik 1 was launched
   by an R-7 rocket. It incinerated upon re-entry on January 3, 1958.

   Sputnik was the first of several satellites in the Soviet Union's
   Sputnik program, the majority of them successful. Sputnik 2 followed as
   the second satellite in orbit, also the first to carry an animal, the
   dog Laika. The first failure occurred with Sputnik 3.

Mission

   The Sputnik 1 spacecraft was launched from Baikonur Cosmodrome at
   Tyuratam (370 km southwest of the small town of Baikonur) in
   Kazakhstan, then part of the Soviet Union. The Russian word "Sputnik"
   means "travel companion" ("satellite" in the astronomical sense). The
   full official name, however, translates as "Artificial Earth Satellite"
   (ISZ in Russian literature). In 1885 Konstantin Tsiolkovsky first
   described in his book Dreams of Earth and Sky ( ISBN 1-4147-0163-2) how
   such a satellite could be launched into a low altitude orbit. It was
   planned as a contribution to the International Geophysical Year
   (1957-1958), with three of the five Sputnik satellites reaching orbit
   during that period.

   The actual sequence of decision-making as to the form of Sputnik 1 was
   convoluted. A tonne-and-a-half, cone-shaped artificial satellite
   capable of making many physics measurements in space was first planned
   by Academician Keldysh, but when the Soviets read that the American
   Project Vanguard had two satellite designs, a small one which was just
   to see if they could get something into orbit, the Soviets decided to
   have what translates as the "Simplest Satellite" too, one which was one
   centimeter larger in diameter, and much heavier, than Vanguard's "real"
   satellite. They had to see whether the conditions in low Earth orbit
   would permit the bigger satellite to remain there for a useful length
   of time. When, months after Sputnik 1, the Vanguard test satellite was
   orbited, Khrushchev ridiculed it as a "grapefruit." Once the Soviets
   found they could orbit a test satellite too, they planned to orbit
   Keldysh's space laboratory satellite as Sputnik 3, and did so after one
   launch failure.
                          Instruments
   Nitrogen pressurized sphere : Micrometeorite detection
   Radio :                       Propagation of radio signals
   Thermometer :                 Micrometeorite detection

   The spacecraft obtained data pertaining to the density of the upper
   layers of the atmosphere and the propagation of radio signals in the
   ionosphere. The instruments and electric power sources were housed in a
   sealed capsule and included transmitters operated at 20.005 and 40.002
   MHz (about 15 and 7.5 m in wavelength), the emissions taking place in
   alternating groups of 0.3 s duration. The downlink telemetry included
   data on temperatures inside and on the surface of the sphere.

   Because the sphere was filled with nitrogen under pressure, Sputnik 1
   provided the first opportunity for meteoroid detection (no such events
   were reported), since losses in internal pressure due to meteoroid
   penetration of the outer surface would have been evident in the
   temperature data. The satellite transmitters operated for three weeks
   and were monitored with intense interest around the world, until the
   on-board chemical batteries failed. The orbit of the then-inactive
   satellite was later observed optically to decay 92 days after launch (
   January 4, 1958) after having completed about 1400 orbits of the Earth,
   travelling a cumulative distance of 70 million kilometers. The orbital
   apogee declined from 947 km after launch to 600 km by December 9.

   The Sputnik 1 rocket booster also reached Earth orbit and was visible
   from the ground at night as a first magnitude object. The satellite
   itself, a small but highly polished sphere, was barely visible at sixth
   magnitude, and thus more difficult to follow optically. Several
   replicas of the Sputnik 1 satellite can be seen at museums in Russia
   and another is on display in the Smithsonian National Air and Space
   Museum in Washington, D.C.

Space race

   The United States had also been working on satellites, primarily
   through teams working for the US Navy as Project Vanguard. Their first
   launch had originally been intended to go before Sputnik, but was
   delayed several times before eventually blowing up on the pad. A rush
   effort then started under the US Army's Jupiter project and succeeded
   launching Explorer I in January 1958. This is considered the start of
   the Space Race between the two superpowers, as an aspect of the Cold
   War. Both nations attempted to out-do each other in space exploration,
   eventually culminating in the launch of the Apollo 11 mission to the
   Moon.

Historical preservation

   In 2003 a back-up unit of Sputnik 1 called "model PS-1" was sold on
   eBay (minus the classified military radio parts that were removed in
   the 1960s). It had been on display in a science institute near Kiev. It
   is estimated that between four and twenty models were made for testing
   and other purposes.

   A Sputnik 1 model was given as a present to the United Nations and now
   decorates the entry Hall of its New York City Headquarters.

   Retrieved from " http://en.wikipedia.org/wiki/Sputnik_1"
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