The primary National Aeronautics and Space Administration (NASA) site for control and operations of U.S. lunar and interplanetary missions.
The Jet Propulsion Laboratory, located in Pasadena, California, evolved from a project in rocket propulsion that began in the early 1930’s. During that time, one of the leading organizations in aeronautics study and research was the Guggenheim Aeronautical Laboratory at the California Institute of Technology (GALCIT), directed by Dr. Theodore von Kármán, also in Pasadena. In 1936, graduate student Frank J. Malina successfully approached von Kármán with a proposal to write his doctoral dissertation on rocket propulsion and high-altitude sounding rockets. This early work in rocket propulsion attracted the attention of two local rocket enthusiasts, John Parsons and Ed Forman. Together, the four men worked through the theories of rocket propulsion and designed a rocket engine, with some insights gained from a meeting with rocket pioneer Robert H. Goddard.
Because no safe campus facilities were available at which to test the rocket engine, Malina, Parsons, and Forman drove to an isolated site a few miles from the California Institute of Technology (Caltech) in the Arroyo Seco wilderness area. Although their first few tests were unsuccessful, the men eventually developed a working rocket engine. Their early successes with rocket engines gained the group facilities on the Caltech campus in which to continue their work.
In 1938, GALCIT was awarded a grant to study the possibility of using rockets to assist U.S. Army Air Corps aircraft on takeoff from short runways. A much larger grant from the National Academy of Sciences was awarded in 1939 to continue the jet-assisted takeoff (JATO) rocket work, signaling the beginnings of a significant shift for GALCIT’s rocket project, from research for sounding rockets to research for military applications. In 1943, von Kármán produced a report, together with Malina and Qian Xuesen, on rocket research at GALCIT and proposed a significant expansion of rocket research, including a proposal to construct missiles capable of carrying explosive warheads and investigations of ramjet engines. This report contained the first usage of the term Jet Propulsion Laboratory to describe the GALCIT rocket facilities that had been constructed for the JATO work.
Though the laboratory’s research was focused primarily on rocket propulsion technology, von Kármán chose the name Jet Propulsion Laboratory over Rocket Propulsion Laboratory. There may have been several reasons for this choice. Because rockets propel themselves through jets of gas, the term “jet propulsion” is more general than “rocket propulsion” and technically more accurate. Furthermore, by not limiting the scope of the laboratory to rocket research, von Kármán was leaving the door open for the laboratory to continue the original GALCIT work in other fields of aeronautical research. In addition, many military minds may have mentally associated the term “rocket” with fireworks. Jet propulsion was a new technical term that would more readily have caught their attention. Finally, due to the preponderance of poorly written science fiction about rockets and rocket ships and the negative publicity many amateur rocket enthusiasts had garnered, the term “rocket” had come to carry an unfavorable connotation, which von Kármán may have been trying to avoid.
In 1944, the Army authorized a $1,600,000 grant to construct a major research and development facility for rocketry and guided missile research operated under contract by Caltech. The new facility was officially named the Jet Propulsion Laboratory, GALCIT. The new JPL was charged with the mission of carrying forth several separate areas of research: rocket engine research, underwater solid-fueled missiles, ramjet research, and long-range heavy missile research, most of which had been mentioned in von Kármán’s proposal the year before. At about this time, von Kármán left both Caltech and JPL, and the directorship of the now-official Jet Propulsion Laboratory fell to his former graduate student, Dr. Frank Malina.
To measure performance of their rockets, JPL’s engineers and scientists developed radio telemetry techniques to monitor their missiles in flight. Telemetry is data transmitted from a remote location by radio signals. To track its missiles, JPL also developed a series of ground radio and radar stations. By 1945, JPL had launched rockets from White Sands, New Mexico, to altitudes of nearly 30 miles. The JPL team eventually developed the technology for two-way radio control of the rockets. In 1947, JPL launched the Bumper-Wac rocket, which first carried an American payload to the edge of space.
By the late 1940’s, JPL had developed the Corporal missile, the United States’ first operational surface-to-surface missile. By the early 1950’s, researchers at JPL had designed the first solid-fueled antiaircraft missiles. In 1954, JPL proposed Project Orbiter, which would use a Redstone rocket as a first stage and either Loki or Sergeant rockets as upper stages, to put an artificial satellite into orbit around the earth by as early as 1957. The project was rejected. In October, 1957, however, the Soviet Union placed its Sputnik satellite into orbit. After Sputnik, JPL was given the go-ahead on its orbital project. Redstone would provide the missile, but JPL would design the payload and upper stage of the rocket to put the satellite into orbit. JPL would also handle tracking of the satellite. Finally, on January 31, 1958, the United States launched JPL’s satellite, which was named Explorer 1.
With Explorer 1, JPL had once again shifted its emphasis, which now focused on the electronics and communications involved in fabricating a satellite rather than on the rocket used to launch the satellite. Following Explorer 1, JPL, under the Army’s supervision, was responsible for the development and operation of several other uncrewed Explorer spacecraft.
Prior to launch of Explorer 1, several different government agencies were involved in space-related activities. It was deemed advantageous, however, to put all space-related activities except for certain military applications, under one civilian agency’s jurisdiction. Thus, on October 1, 1958, the National Aeronautics and Space Administration (NASA) was created. On December 3, 1958, JPL was transferred from the jurisdiction of the Army to that of NASA but would continue to be operated by Caltech, under contract with NASA. The role of JPL under NASA would be primarily one of satellite and space probe design and operations. Although JPL was responsible for the Deep Space 1 spacecraft, which successfully tested an ion-drive propulsion engine, very little rocket propulsion work continued at JPL after this time.
NASA continued the expansion programs at JPL’s Pasadena site that had begun under the Army’s administration. Additional scientists and engineers were hired, and new facilities were built, so that JPL came to be situated on 177 acres of land near where von Kármán’s team had done its original rocket propulsion experiments. Although under NASA, the Jet Propulsion Laboratory ceased research in jet or rocket propulsion, its original name remains in use.
By the year 2001, JPL had been responsible for nearly 60 spacecraft missions, as well as numerous payloads flown on space shuttle missions. Although a few of these missions failed to perform as expected or were lost due to launch vehicle or spacecraft failures, most missions were successful. Several JPL missions, such as the Voyager missions to the outer solar system, many of the Mariner missions to the inner planets, the Galileo mission to Jupiter, the Magellan mission to Venus, and the Viking missions to Mars, have enjoyed spectacular successes. Under NASA, JPL has achieved dominance in the field of lunar and planetary exploration, having successfully handled missions to every planet in the solar system except for Pluto, as well as missions to several asteroids. Although studies of Earth were largely carried out by other NASA centers, JPL has also played a key role in several missions studying the planet Earth.
When Explorer 1 was to be placed into orbit in 1958, scientists immediately realized that there would be difficulty monitoring it. As the earth turned beneath the satellite, the groundtrack, or location on the surface of the earth underneath the spacecraft, would shift to the west with each orbit and not all of the orbits would pass over the United States. The satellite would be overhead in the United States only for a short period of each orbit that did pass over the United States. To track and monitor the satellite, therefore, JPL was responsible for deploying portable radio tracking equipment to several sites around the world. Two other Explorer spacecraft were successfully launched, and two more were lost during launch vehicle failure, before JPL was transferred from the Army to NASA. All these satellites needed remote facilities for tracking, telemetry, and control. The original equipment and sites used for Explorer 1 would suffice for the later missions, so that new facilities for each mission would not have to be built and deployed. This decision paved the way, however, for more permanent tracking and telemetry stations.
After JPL was transferred to NASA, a decision was made to build permanent tracking and telemetry stations to support the large number of planned space missions, both crewed and uncrewed. These stations formed the backbone of the Deep Space Network (DSN), operated for NASA by JPL. The core of the DSN is composed of three large communications complexes located near Madrid, Spain, near Canberra, Australia, and at Goldstone, in California’s Mojave Desert. These sites are located nearly 120 degrees apart on the earth’s surface and thus can provide whole-sky coverage. Nearly any portion of the sky is above the horizon from at least one of the DSN sites. Each site has several antennas for telemetry and two-way communications with spacecraft.
Because many of NASA’s space probes have traveled a long way from Earth, the signals from these space probes have become increasingly weak. The DSN has located at each site a 230-foot diameter parabolic dish, forming one of the most sensitive and powerful telecommunications systems on Earth. Also located at each site are 112-foot-diameter, high-efficiency dishes for use with slightly stronger signals. Each site also holds 85-foot-diameter dishes on mounts designed to track satellites in fast-moving orbits near Earth. Each site also holds a 36-foot-diameter dish, each of which can be linked together with those of the other sites for astronomical use in a technique known as long-baseline interferometry.
Although JPL is known primarily for its roles in the early years of American rocket research and in the design and control of NASA spacecraft, JPL has also been involved in several other noteworthy projects. Many of these projects are natural spin-offs and extensions of the technologies that were developed for uncrewed spacecraft operations. JPL has played an important role in the study of solar energy as an alternate source of energy. JPL has also worked to develop an airborne, infrared fire-spotting system for the U.S. Forest Service. JPL has been involved in the advancement of robotics and automation and the development of miniature sensors and instrumentation. To deal with the enormous volume of data returning from space probes, JPL has also developed new, more powerful computer technologies, many of which have found their way into everyday non-space-related applications.
Anderson, Frank W., Jr. Orders of Magnitude: A History of NACA and NASA, 1915-1980. 2d ed. Washington, D.C.: Government Printing Office, 1981. A history the U.S. space agency, including uncrewed space exploration. Jet Propulsion Laboratory. Deep Space Network. Pasadena, Calif.: Author, 2000. This pamphlet, part of the NASA Facts series, describes the facilities and operations of NASA’s Deep Space Network. _______. Jet Propulsion Laboratory. Pasadena, Calif.: Author, 2000. This pamphlet, part of the NASA Facts series, describes JPL’s history and many of the missions operated by the laboratory. Koppes, Clayton R. JPL and the American Space Program. New Haven, Conn.: Yale University Press, 1982. A very thorough and well-researched history of the Jet Propulsion Laboratory.
Aerospace industry, U.S.
Robert H. Goddard
National Aeronautics and Space Administration