Jet Propulsion Laboratory

JPL traces its roots to the 1930s, when Caltech professor Theodore von Kármán and graduate students Frank Malina, Jack Parsons, and Edward Forman conducted rocket experiments in the Arroyo Seco, a dry riverbed near Pasadena. Their work, initially motivated by amateur interest, led to the founding of the Guggenheim Aeronautical Laboratory and later the Jet Propulsion Laboratory in 1944, under a contract with the U.S. Army. During World War II, JPL developed solid- and liquid-fueled rockets, including the JATO (jet-assisted takeoff) units used by military aircraft.¹

After the war, JPL shifted toward guided missile technology, producing the Corporal and Sergeant ballistic missiles. In 1958, following the launch of Sputnik, JPL was transferred to the newly created NASA, and its focus turned to space exploration. The laboratory's first major success was the Explorer 1 satellite, launched in January 1958, which discovered the Van Allen radiation belts.²

JPL's planetary exploration program began in earnest with the Mariner missions to Venus and Mars in the 1960s. Mariner 2 (1962) became the first spacecraft to fly by another planet, and Mariner 4 (1965) returned the first close-up images of Mars. The Viking landers (1976) conducted the first in-situ search for life on Mars, and the Voyager spacecraft (launched 1977) explored the outer planets and continue to operate in interstellar space.³

In the 1990s and 2000s, JPL led the Mars Pathfinder, Spirit, Opportunity, and Curiosity rovers, which have revolutionized understanding of Martian geology and habitability. The laboratory also managed the Cassini mission to Saturn (1997–2017), the Juno orbiter at Jupiter, and the InSight lander. More recently, JPL built and operated the Perseverance rover, which landed in Jezero Crater in 2021 to collect samples for future return to Earth.⁴

JPL operates the Deep Space Network (DSN), a global array of radio antennas in Goldstone (California), Madrid (Spain), and Canberra (Australia). The DSN provides two-way communication with spacecraft beyond low Earth orbit, supporting navigation, telemetry, and science data return. It has been essential for every interplanetary mission, from the early Mariner probes to the Voyager interstellar spacecraft.⁵

Beyond mission operations, JPL is a hub for advanced technology development. It pioneered the use of radioisotope thermoelectric generators (RTGs) for deep-space power, developed the first digital image processing techniques for spacecraft imagery, and has contributed to innovations in robotics, microelectronics, and materials science. The laboratory also supports Earth science missions, such as the GRACE and SWOT satellites, which monitor water and ice changes.⁶

JPL's history includes several lesser-known facets. The laboratory's original name was the Jet Propulsion Laboratory, but it was initially part of the Army Ordnance Corps; its transition to NASA in 1958 was a pivotal moment in the U.S. space program. The lab's early rocket tests were conducted in the same Arroyo Seco that later became the site of the Rose Bowl, and the area is now a designated National Historic Landmark.⁷

JPL has also been involved in non-space projects, such as developing the technology for the first implantable pacemaker in the 1960s, in collaboration with Medtronic. The laboratory's "Mission to Planet Earth" program, initiated in the 1990s, used space-based observations to study climate and environmental change. Additionally, JPL's public outreach includes the annual "Open House" event, which attracts tens of thousands of visitors, and its "Eyes on the Solar System" interactive visualization tool, which allows the public to track spacecraft in real time.

Deep Space Network

A global network of antennas used for communication with interplanetary spacecraft.

Radioisotope thermoelectric generator

A device that converts heat from radioactive decay into electricity for spacecraft power.

Van Allen radiation belts

Zones of charged particles trapped by Earth's magnetic field, discovered by Explorer 1.