United States Launches Its First Orbiting Satellite

With the launch of Explorer 1, the United States entered the space age, bolstering the nation’s pride in its technology shortly after the first satellite, Sputnik 1, was launched by the Soviet Union and preparing for a U.S. piloted spaceflight program.

Summary of Event

According to a White House announcement in 1955, the U.S. government was sponsoring a program to place satellites in orbit for the advancement of science. However, in fact, President Dwight D. Eisenhower’s Eisenhower, Dwight D.
[p]Eisenhower, Dwight D.;space program reasons were far more complex: The United States’s prestige as the world’s technological vanguard, national defense, and international law were as important. The complex motivations sometimes hindered as much as helped the fledgling space program, so that by the time Explorer 1 circled Earth on January 31, 1958, the United States was already behind in the space race. The Soviet Union’s Sputnik 1 had achieved orbit four months earlier. Nevertheless, Explorer 1 achieved its most important goals, and it produced a scientific surprise that proved to be fundamentally important to planning later piloted spaceflights. Satellites, artificial;early experimental programs
Explorer program
Space program, U.S.;Explorer program
[kw]United States Launches Its First Orbiting Satellite (Jan. 31, 1958)
[kw]Orbiting Satellite, United States Launches Its First (Jan. 31, 1958)
[kw]Satellite, United States Launches Its First Orbiting (Jan. 31, 1958)
Satellites, artificial;early experimental programs
Explorer program
Space program, U.S.;Explorer program
[g]North America;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
[g]United States;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
[c]Space and aviation;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
[c]Engineering;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
[c]Communications and media;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
[c]Cold War;Jan. 31, 1958: United States Launches Its First Orbiting Satellite[05790]
Braun, Wernher von
Van Allen, James[Vanallen, James]
Stewart, Homer J.
Pickering, William H.

In The Heavens and the Earth: A Political History of the Space Age (1985), Heavens and the Earth, The (McDougall) Walter A. McDougall McDougall, Walter A.[Macdougall, Walter A.] argues that the first government support for a satellite program resulted from the nuclear arms race: Eisenhower wanted a spy satellite that could warn of a Soviet attempt to launch intercontinental ballistic missiles (ICBMs), then being developed by both the United States and the Soviet Union. There was a problem, however. If the military (which possessed the most advanced research facilities) pursued satellite testing, it was feared that the Soviets would accuse the United States of using space for aggression. They would try to make flyovers of their territory illegal in international law. Eisenhower insisted that, unlike national airspace, outer space should be free of restrictions.

An opportunity for peaceful use of spacecraft presented itself in the International Geophysical Year International Geophysical Year (IGY; 1957-1958), with an effort to encourage worldwide cooperation in science. In 1955, at the urging of the National Science Foundation, the U.S. government began plans to celebrate IGY by orbiting a satellite. Eisenhower’s advisers were confident that no objections could be raised to the project, since it was ostensibly a purely civilian research effort. Once a satellite had been orbited, precedent would be set for unrestricted use of outer space. Meanwhile, the Soviet Union had begun a similar project.

Explorer I is launched on January 31, 1958.


The Department of Defense was placed in charge and established an advisory committee of nine members headed by Homer J. Stewart of the Jet Propulsion Laboratory (JPL) to select a vehicle and payload. There were three candidates: the U.S. Air Force’s World Series satellite based on the Atlas ICBM; the U.S. Army and JPL’s Explorer, which used a modified Redstone missile; and the U.S. Navy’s Vanguard satellite and Viking booster. Even though the Army’s proposal showed the clearest promise for an early launch date, the committee chose the Navy’s Viking-Vanguard Project Vanguard by a one-vote margin.

Vanguard was beset with problems from the outset. The Department of Defense allocated funding priority to warhead-carrying ICBMs, so the satellite project was chronically underfunded. As the Viking booster had to be redesigned after early testing failures, delay followed delay. Pressure mounted steadily for a successful launch, especially after the Soviets placed Sputnik 1 in orbit on October 4, 1957, followed by Sputnik 2 on November 3. The Navy team rushed to get Vanguard into space; the first attempt failed spectacularly. On December 6 it rose a few feet above its launchpad, then sank back to Earth in flames.

Although it had not received authorization, the Army satellite team had been working quietly on its rejected candidate, with Stewart’s unofficial encouragement. Headed by Wernher von Braun, it assembled and tested a workable launch vehicle, the Jupiter-C, and waited on the sidelines in case the Navy Vanguard project failed, as the first attempt did. When malfunctions delayed a second attempt to launch Vanguard on January 27, 1958, the secretary of defense, Neil H. McElroy McElroy, Neil H.[Macelroy, Neil H.] , told the Army to try Explorer.

Four days later, at 10:38 p.m., the four-stage Jupiter-C rocket Rockets
Jupiter- C rocket[Jupiter C rocket] successfully blasted off from Cape Canaveral, Florida. Reaching a speed of about 29,000 kilometers (18,000 miles) per hour, it lifted the 13.9-kilogram (30.5-pound) last stage and instrument payload into an elliptical orbit, with a high point of 2,554 kilometers (1,587 miles) and a low point of 352 kilometers (219 miles). The news of success cheered the nation; Explorer not only had equaled the achievement of the Sputniks but also had reached a higher orbit.

The Jupiter-C rocket was a direct descendant of the German V-2 rockets used to bombard England during World War II. Von Braun, who had designed the V-2, had come to the United States in hopes of using his skills to build spacecraft. He adapted and enlarged the V-2 design for that purpose, even though the Army had instructed him to work primarily on building weapon-delivering rockets. The first stage of the Jupiter-C was von Braun’s Redstone rocket, which stood 21 meters (69 feet) tall, was fueled by liquid oxygen and hydrogen, and which boosted to an altitude of 85 kilometers (53 miles) in 145 seconds. It then detached, and the remaining three stages, all clusters of solid-fuel rockets, coasted to an altitude of approximately 341 kilometers (212 miles). One after another, von Braun’s assistants rapidly ignited these stages by remote control until the final one accelerated to orbital velocity. The whole assembly was set spinning before takeoff to stabilize the rocket in flight. This multistaged design had been developed at JPL, under the direction of William H. Pickering.

James Van Allen designed and built the Explorer 1 payload at the University of Iowa. A tube 1.8 meters by 20.3 centimeters (5.9 feet by 8 inches) in length and 15.2 centimeters (6 inches) in diameter (including the final booster), the satellite contained instruments for measuring temperature and radiation levels in space and detecting the impacts of micrometeoroids, as well as two radios for transmitting the data back to Earth.

The Geiger counter aboard Explorer 4 led to the first major scientific discovery by a space probe. Van Allen had expected to encounter increased radiation above Earth’s atmosphere, but the instrument became so saturated with high-level radiation that at first he thought it had malfunctioned. Later satellites recorded similar intensities; Van Allen eventually mapped the two toroidal zones of high radiation that gird Earth, zones now known as the Van Allen radiation belts.


Explorer 1 boosted the United States’s technological self-esteem, sagging after the Soviet Union achieved orbit first. Its real importance, however, lay in its contribution to the understanding of outer space and the establishment of the National Aeronautics and Space Administration National Aeronautics and Space Administration;Explorer program (NASA).

Diagram of the Explorer I satellite.


The interservice rivalry among the Army, Navy, and Air Force for research money was as much responsible for delaying the nation’s entry into the space age as the difficulties in developing the new technology. That fact was evident to the scientists at work in rocketry research and to the politicians who oversaw expenditures. It became abundantly clear to President Eisenhower and Senate Majority Leader Lyndon B. Johnson Johnson, Lyndon B.
[p]Johnson, Lyndon B.;space program , who led the congressional initiatives for space exploration, that space research and development had to be removed from the control of the military. They thought that only an independent agency would assure efficient use of money, produce the safest vehicles, and allow the widest application of space technology through public access to the fruits of the research.

So, on October 1, 1958, NASA began operation, taking over many of the facilities and research staffs devoted to satellites by the armed services. If such an agency had not been created, and created quickly, the space program of the United States might well have stayed a poor stepchild of military ICBM programs and been drastically delayed in realizing piloted spaceflights, deep-space exploration by scientific probes, and the many practical benefits to weather forecasting and communications made possible by satellites.

Von Braun’s Redstone rocket proved to be a reliable launch vehicle. The thorough testing conducted during the early Explorer launches, in part, qualified it as the booster for the United States’s first piloted spaceflight in 1961. To keep weight to a minimum, Van Allen also pioneered techniques to miniaturize instrumentation and telemetry components.

Perhaps the most revealing fact about the launch of Explorer 1 and the United States’s entry into the space age was how readily the nation accepted the venture. Dissenters decried the vast amounts of money devoted to space as wasteful of tax dollars better spent on social programs, but they were relatively few. The majority of Americans either approved of or did not object to space exploration and the technocracy it entailed. Development of the frontier had always been part of the American mentality, and space became a new frontier, especially after May, 1961, when President John F. Kennedy announced a program to land Americans on the moon. Satellites, artificial;early experimental programs
Explorer program
Space program, U.S.;Explorer program

Further Reading

  • Bille, Matt, and Erika Lishock. The First Space Race: Launching the World’s First Satellites. Austin: University of Texas A&M Lightning Source Titles, 2004. A thorough history of the U.S. Army’s and Navy’s roles in launching the first U.S. satellites, and a history of Project Vanguard.
  • Bilstein, Roger E. Orders of Magnitude: A History of the NACA and NASA, 1915-1990. Washington, D.C.: Government Printing Office, 1989. This official history of NASA and its predecessor, the National Advisory Committee for Aeronautics, provides basic information on Explorer 1. It summarizes the various political influences and research efforts that preceded the launch. A readable overview with many photographs.
  • Cadbury, Deborah. Space Race: The Epic Battle Between America and the Soviet Union for Dominion of Space. New York: HarperCollins, 2006. An account of efforts to launch the first satellite and to send humans to the moon. Although focusing on the two chief designers, Wernher von Braun and Sergei Korolev, this 384-page history includes an excellent account of Project Vanguard.
  • Green, Constance M., and Milton Lomask. Vanguard: A History. Washington, D.C.: Smithsonian Institution Press, 1971. This detailed history of the early satellite programs concentrates on Vanguard but also chronicles the achievements of its chief rival: the Explorer series. What emerges most clearly is the consternation of scientists involved in the project, who endured ridicule and pressure from the constant media scrutiny of their failures.
  • McDougall, Walter A. The Heavens and the Earth: A Political History of the Space Age. 1985. New ed. Baltimore: Johns Hopkins University Press, 1997. An excellent critical study of the military and political support for the U.S. venture into space. The story of Eisenhower’s goal in funding satellite research and the chagrin and confusion of the scientists involved is especially well told and thoroughly documented. McDougall also philosophizes provocatively on the dangers of aerospace technocracy, a welcome change from the non-analytical enthusiasm of most histories of spaceflight.
  • Newell, Homer E. Beyond the Atmosphere: Early Years of Space Science. Washington, D.C.: Government Printing Office, 1980. Newell gives an insider’s account of the background of NASA’s creation. The focus is therefore on organizational history; but along the way, the Explorer project receives attention as—along with Vanguard—one of the primary examples of why a unified, nonmilitary agency was needed to develop the nation’s space program.
  • Porter, Richard W. The Versatile Satellite. New York: Oxford University Press, 1977. Porter summarizes the progress of satellite history trenchantly, but his book is particularly valuable to those new to space science for its lucid explanations of basic rocketry, the nature and value of the scientific discoveries that satellites have made possible, and their many practical uses. Contains a wealth of color and black-and-white photographs, illustrations, maps, graphs, and tables.
  • Sullivan, Walter. Assault on the Unknown: The International Geophysical Year. New York: McGraw-Hill, 1961. Gives a well-written critical account of the satellite race and its place in the celebration of IGY. Written shortly after the events, the book reveals the temper of the time: optimism in the technological future.

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