The space age began with the October 4, 1957 launch of the first Russian space satellite. Other Sputnik satellites and the first US Explorer satellite soon followed.

Sputnik 1

It will soon be the 50th anniversary of the dawn of the space age. The space age began with the October 4, 1957 launch of the first artificial space satellite, Sputnik 1. The name Sputnik comes from Russian for "companion" or "fellow traveler".

Sputnik 1 was a very simple satellite. It was a highly polished aluminum sphere. Sputnik 1 was 22 inches in diameter and weighed 183 pounds. Radio antennas extended from the sphere.

The first Sputnik's only instrumentation was a battery powered radio transmitter and thermometer. Sputnik sent radio telemetry back to Earth. It orbited Earth every 98 minutes and fell back to Earth on January 4, 1958. The importance of this first Sputnik was not the data or telemetry but the simple fact that a manmade object had been launched into orbit.

Sputnik 2

When they realized the impact of the first Sputnik, Soviet leaders asked for a larger satellite launch in time to celebrate the 40th anniversary of the Russian revolution. Sputnik 2 was designed and built very quickly. It launched less than a month later on November 3, 1957.

Sputnik 2 was considerably larger. The 1,120 pound satellite carried the first passenger into space. A dog, Laika, traveled into space, but soon died when the capsule overheated. The satellite however remained in orbit a little over 6 months.

Sputnik 3

The first attempt to launch Sputnik 3 on April 27, 1958 failed. Sputnik 3 was however successfully launched on May 15, 1958. The 1.5 ton satellite contained a scientific payload with scientific instruments for measuring the conditions in space.

Impact of Sputnik

During the cold war in the 1950s, there was considerable competition between the United States and Soviet Union. Each country also had considerable paranoia and fear of the military aims of the other. Hence the United States worried both that the Soviet Union won the race to be first in space and that the Soviets could launch military ballistic missiles at the US.

In response the United States space program sprang into action. To lead the fledgling US space program, Congress created NASA on October 1, 1958.

First US Satellites

Initially the United States had planned to launch a Vanguard satellite with an embarrassingly small 3.5 pound payload. This attempted launch failed. It exploded on the launch pad on December 6, 1957.

The first successful US satellite was the Explorer 1 which was launched on January 31, 1958. This Explorer satellite contained a scientific payload built by James Van Allen, a professor at the University of Iowa. Explorer 1 discovered the Van Allen belts. Even though the United States did not launch the first satellite, it could claim the first major discovery from a satellite.

In the intervening 50 years satellite launches have become so common that there are now about 12,000 artificial satellites orbiting Earth.

Further Reading

NASA History

Sky and Telescope, October 2007