History changed on October 4, 1957, when the Soviet Union successfully launched Sputnik I. The world's first artificial satellite was about the size of a basketball, weighed only 183 pounds, and took about 98 minutes to orbit the Earth on its elliptical path. That launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the U.S.-U.S.S.R space race.

The story begins in 1952, when the International Council of Scientific Unions decided to establish July 1, 1957, to December 31, 1958, as the International Geophysical Year (IGY) because the scientists knew that the cycles of solar activity would be at a high point then. In October 1954, the council adopted a resolution calling for artificial satellites to be launched during the IGY to map the Earth's surface.

In July 1955, the White House announced plans to launch an Earth-orbiting satellite for the IGY and solicited proposals from various Government research agencies to undertake development. In September 1955, the Naval Research Laboratory's Vanguard proposal was chosen to represent the U.S. during the IGY.

The Sputnik launch changed everything. As a technical achievement, Sputnik caught the world's attention and the American public off-guard. Its size was more impressive than Vanguard's intended 3.5-pound payload. In addition, the public feared that the Soviets' ability to launch satellites also translated into the capability to launch ballistic missiles that could carry nuclear weapons from Europe to the U.S. Then the Soviets struck again; on November 3, Sputnik II was launched, carrying a much heavier payload, including a dog named Laika.

Immediately after the Sputnik I launch in October, the U.S. Defense Department responded to the political furor by approving funding for another U.S. satellite project. As a simultaneous alternative to Vanguard, Wernher von Braun and his Army Redstone Arsenal team began work on the Explorer project.

On January 31, 1958, the tide changed, when the United States successfully launched Explorer I. This satellite carried a small scientific payload that eventually discovered the magnetic radiation belts around the Earth, named after principal investigator James Van Allen. The Explorer program continued as a successful ongoing series of lightweight, scientifically useful spacecraft.

The Sputnik launch also led directly to the creation of National Aeronautics and Space Administration (NASA). In July 1958, Congress passed the National Aeronautics and Space Act (commonly called the "Space Act"), which created NASA as of October 1, 1958 from the National Advisory Committee for Aeronautics (NACA) and other government agencies.

Sputnik
Sputnik and the Origins of the Space Age
Written by Roger D. Launius.
Korolev's Triple Play
All about Sputniks 1, 2, and 3, written by James Harford
Korolev, Sputnik And The International Geophysical Year
Written by Asif A. Siddiqi
Biographies of Those Involved with Sputnik

Firsts in Satellite History
October 4, 1957 The Russian Sputnik 1 is the first satellite in space. Russia becomes the first space power. November 3, 1957 A dog named 'Laika' is the first living creature in space.

Explorer-1 and Jupiter-C
Explorer-I, officially known as Satellite 1958 Alpha, was the first United States earth satellite and was sent aloft as part of the United States program for the International Geophysical Year 1957-1958.

Applications Satellites
NASA did pioneering work in space applications such as communications satellites in the 1960s. The Echo, Telstar, Relay, and Syncom satellites were built by NASA or by the private sector based on significant NASA advances.

In the 1970s, NASA's Landsat program literally changed the way we look at our planet Earth. The first three Landsat satellites, launched in 1972, 1975, and 1978, transmitted back to Earth complex data streams that could be converted into colored pictures. Landsat data has been used in a variety of practical commercial applications such as crop management and fault line detection, and to track many kinds of weather such as droughts, forest fires, and ice floes. NASA has been involved in a variety of other Earth science efforts such as the Earth Observation System of spacecraft and data processing that have yielded important scientific results in such areas as tropical deforestation, global warming, and climate change.

Communications Satellites
Starts with a useful overview of the early history of satellite communications and includes information on NASA's current Advanced Communications Technology Satellite.

Weather Satellites
Check out information on programs such as Tiros and Nimbus.

Earth Science Satellites
NASA has been involved with projects ranging from Landsat to TOPEX/POSEIDON and the Earth Observing System (EOS).

Telemetry
Highly automated communications process by which measurements are made and other data collected at remote or inaccessible points and transmitted to receiving equipment for monitoring.

images provided by NASA
©Mary Bellis