Welcome to JPL: This is what greeted visitors in December 1957. There is no sign at this location today -- instead there is just a stairway that runs up the side of the main administration building (Building 180). The official lab sign has moved farther south, just as the lab itself has expanded farther south out from the base of the San Gabriel Mountains. The “now” picture is from October 2016.

› View all then & now pictures

JPL grew up with the Space Age and helped bring it into being. It is a place where science, technology, and engineering intermix in unique ways: to produce iconic robotic space explorers sent to every corner of the solar system, to peer deep into the Milky Way galaxy and beyond, and to keep a watchful eye on our home planet. Analyzing the data pouring back from these machine emissaries, scientists around the world continue to discover how the universe, the solar system, and life formed and evolved.

The Early Years

JPL's beginnings can be traced to the mid-1930s, when a few Caltech students and amateur rocket enthusiasts started tinkering with rockets. After an unintended explosion occurred on campus, the group and its experiments relocated to an isolated area next to the San Gabriel Mountains, the present-day site of JPL. In the following decade, as an anxious country sought to respond to the menacing challenge of German V-2 rockets, the fledgling Jet Propulsion Laboratory (officially named in 1944, some 14 years before NASA was formed) was sponsored by the U.S. Army to develop rocket technology and the Corporal and Sergeant missile systems.

Becoming Part of the NASA Family

The early years of space exploration were fueled by the Cold War. The Soviet Union won the first round in October 1957 by placing Sputnik into Earth orbit. The "beep-beep" sound transmitted by the satellite was nervously heard around the free world, and pressure mounted for the United States to respond. In less than three months, JPL had built Explorer 1, launched in January 1958 to become America's first satellite. Even this first spacecraft made an important scientific discovery: it detected what would become known as the Van Allen radiation belts encircling Earth, named after James Van Allen, the scientist who designed the main instrument on Explorer 1. The National Aeronautics and Space Administration was founded in October 1958, and JPL was transferred from the Army to the new agency. The transition from the Army to NASA also marked another change. The Laboratory began to turn its attention from the rockets themselves to the payloads they would carry. Developing these payloads - scientific spacecraft - would become the new focus and place JPL at the center of the Space Race with the Soviet Union. Even though the Laboratory's charter had completely evolved away from rockets and jets, "Jet Propulsion Laboratory" had become the official name and was retained. Another defining moment for America in space came in 1962, when the JPL-built Mariner 2 flew past Venus to become the world's first spacecraft to successfully encounter another planet. Thus commenced a long series of "first ever" accomplishments by JPL that helped define history's first five decades of space exploration. JPL has a unique position within the NASA family. Ever since its transfer to NASA, JPL has been structured as an FFRDC(Federally Funded Research and Development Center) dedicated to the robotic exploration of space. The Laboratory is NASA's only FFRDC and works alongside NASA's nine field centers. However, unlike those centers, which are staffed by government civil servants, JPL is managed for NASA by Caltech under a contractual arrangement begun in 1958 and renewed every five years. Thus, JPLers are Caltech employees.

Famous Firsts Built in JPL's Spacecraft Assembly Facility

History is being made all the time in JPL's Spacecraft Assembly Facility. Here are all the missions that have passed through (by launch date):

First flyby to Venus: Mariner 2, 1962

First U.S. probe to send back images of the Moon: Ranger 7, 1964

First flyby to Mars: Mariner 4, 1964

First orbiter to Mars: Mariner 9, 1971

First probe to exit the heliosphere: Voyager 1, 1977

First probe to flyby four planets: Voyager 2, 1977

First orbiter to Jupiter: Galileo, 1989

First orbiter to Saturn: Cassini, 1997

First rover on Mars: Sojourner (part of Pathfinder), 1997

Era of Large Space Missions

In the 1970s, 1980s, and early 1990s, NASA focused JPL's expertise on large, complex, one-of-a-kind space missions. This era produced the Voyagers to the outer planets, the Vikings to Mars (in partnership with NASA's Langley Research Center), the Galileo mission to the Jupiter system (in partnership with NASA's Ames Research Center), and Cassini-Huygens to the Saturn system (in partnership with the European Space Agency and the Italian Space Agency). These legendary spacecraft extended humanity's senses throughout the solar system, letting us examine the planets and moons up close.