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Sputnik 1
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Sputnik 1

Sputnik 1
Organization: Soviet Union
Major Contractors: Korolev Design Bureau
Mission Type: Earth Science
Satellite of: Earth
Launch: October 4, 1957 at 19:12 UTC
Launch Vehicle: R-7/SS-6 ICBM
Decay: January 4, 1958
Mission Duration: 3 weeks
Mass: 83.6 kg
NSSDC ID: 1957-001B
Webpage: NASA NSSDC Master Catalog
Orbital elements
Semimajor Axis: 6,955.2 km
Eccentricity: .05201
Inclination: 65.1
Orbital Period: 96.2 minutes
Apogee: 939 km
Perigee: 215 km
Orbits: ~1,400
Instruments
Nitrogen pressurized sphere : Micrometeorite detection
Radio : Propagation of radio signals
Thermometer : Micrometeorite detection

Sputnik 1 was the first artificial satellite to be launched into orbit, on October 4, 1957. The satellite had a weight of about 83 kg (184 pounds). It had two radio transmitters and is believed to have orbited Earth at about 250 km (150 miles) above Earth's surface. Analysis of the radio signals were used to gather information about the upper atmosphere. The Sputnik was launched by an R-7 rocket. Sputnik 1 incinerated upon reentry on Jan. 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.

The Sputnik 1 spacecraft was the first artificial satellite successfully placed in orbit around the Earth and was launched from Baikonur Cosmodrome at Tyuratam (370 km southwest of the small town of Baikonur) in Kazakhstan, then part of the former Soviet Union. The Russian word "Sputnik" means "companion" ("satellite" in the astronomical sense). In 1885 Konstantin Tsiolkovsky first described in his book, Dreams of Earth and Sky, how such a satellite could be launched into a low altitude orbit. It was the first in a series of four satellites as part of the Sputnik program of the former Soviet Union and was planned as a contribution to the International Geophysical Year (1957-1958). Three of these satellites (Sputnik 1, 2, and 3) reached Earth orbit.

The Sputnik 1 satellite was a 58.0 cm-diameter aluminum 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. 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 in duration. The downlink telemetry included data on temperatures inside and on the surface of the sphere.

Since 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, until the on-board chemical batteries failed, and were monitored with intense interest around the world. 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 over a cumulative distance traveled of 70 million kilometers. The orbital apogee declined from 947 km after launch to 600 km by Dec. 9th.

The Sputnik 1 rocket booster also reached Earth orbit and was visible from the ground at night as a first magnitude object, while the small but highly polished sphere barely visible at sixth magnitude 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.

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 launch before Sputnik, but was delayed several times before 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 outdo each other in space exploration, eventually culminating in the launch of the Apollo 11 mission to the Moon. Sputnik 1 fell back to Earth on January 4, 1958.

In 2003 a back-up unit of Sputnik 1 called "model PS-1" was sold on eBay (minus the classified military radio part 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 I Model was given as a present to the United Nations and now decorates the entry Hall of its New York City Headquarters.

See also


See also: Space exploration, Crewless space mission, Sputnik crisis
Hear also:

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First satellite
Sputnik program Next Mission:
Sputnik 2