Sputnik 1
Sputnik 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.
Encyclopedia
Sputnik 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 . 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. It had two
radio transmitters and is believed to have orbited Earth at a height of about 250 km . 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.
| Instruments |
|---|
| Nitrogen pressurized sphere : | Micrometeorite detection |
| Radio : | Propagation of radio signals |
| Thermometer : | Micrometeorite detection |
|
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 in
Kazakhstan, then part of the
Soviet Union. The Russian word "Sputnik" means "travel companion" . The full official name, however, translates as "Artificial Earth Satellite" .
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 planned as a contribution to the International Geophysical Year , 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.
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 , 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 , 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 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 was the first manned mission to land on the Moon [i]. ...
mission to the
Moon.
Historical Preservation
In 2003 a back-up unit of Sputnik 1 called "model PS-1" was sold on
eBay . 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.
See also
- Sputnik crisis - The crisis in the US that this surprise launch of the world's first artificial satellite led to.
- ILLIAC I - First computer to calculate the orbit of Sputnik I.
- Defense Advanced Research Projects Agency
External links
