Jet Propulsion Laboratory (JPL)

Chapter 1 · 1936 – 1957 An engine in the ravine

The laboratory that sent almost every American rover to Mars was born from a rocket-motor test, on Halloween, in a dry riverbed near Pasadena.

October 31, 1936

In the mid-1930s, at the California Institute of Technology, Professor Theodore von Kármán oversaw research on rocket propulsion. One of his students, Frank Malina, and other young researchers took their tests to the Arroyo Seco, a ravine north of the Rose Bowl in Pasadena. On October 31, 1936, they first tested an alcohol-fueled rocket motor there. The Jet Propulsion Laboratory dates its birth from that day. Theodore von Kármán led the group from 1938.

The war

In 1942 a Douglas A-20 bomber tested the group’s liquid-fueled motors, designed to help aircraft take off. In 1943 the U.S. Army asked von Kármán to analyze the German V-2 rocket program. The team’s proposal used the name “Jet Propulsion Laboratory” for the first time. In 1944 the Army Ordnance Corps began funding the laboratory; late that year, tests of a small unguided missile, the Private, began in the Mojave Desert. While von Kármán was in Washington, Frank Malina served as acting director from 1944 to 1946. In 1945 staff neared three hundred, and test vehicles reached about 40 miles altitude above White Sands, New Mexico.

From missiles to a missed satellite

Louis Dunn, director from 1946 to 1954, led the Corporal and Sergeant missile programs; the first Corporal launched in May 1947. In 1954 JPL proposed to launch a satellite for the International Geophysical Year; the proposal was rejected. That same year William Pickering became director. In 1956 and 1957 the laboratory flew three re-entry test vehicles. In December 1957 the Navy’s Vanguard rocket, assigned to launch the American satellite, failed on its launch pad.

Sources: JPL, “History” (von Kármán, Frank Malina, the Arroyo Seco, the October 31, 1936 test, the A-20 in 1942, the V-2 and the name in 1943, the 1944 funding, the Private, nearly 300 people and about 40 miles altitude at White Sands in 1945, Corporal in May 1947, the rejected 1954 proposal, the 1956-1957 re-entry vehicles, Vanguard’s failure in December 1957); JPL, “Faces of Leadership: The Directors of JPL” (von Kármán from 1938 to 1944, Malina acting from 1944 to 1946, Dunn from 1946 to 1954 with Corporal and Sergeant, Pickering from 1954); Caltech, announcement of May 22, 2026 (founded by Caltech researchers in 1936).

Chapter 2 · 1958 – 1976 Explorer, Mariner and Viking

Within a few years the missile laboratory became the laboratory of planetary exploration. It prepared the first American satellite, then the first probes to reveal the true face of Mars.

Explorer 1 and NASA

On January 31, 1958, Explorer 1, prepared by JPL, became the first American satellite. It carried James Van Allen’s Geiger counter, which discovered the radiation belts surrounding Earth. On December 3, 1958, two months after NASA began operations, JPL moved from the Army to the space agency. It became an unusual center: since 1958, Caltech has managed it for NASA.

Toward the planets

On August 27, 1962, Mariner 2 left for Venus; it became the first spacecraft to fly by another planet and return data. In 1963 the Deep Space Network was officially founded: three antenna complexes, at Goldstone in California, near Madrid and near Canberra, spaced equally around the world. In 1964 and 1965 Rangers 7, 8 and 9 photographed the Moon before crashing into it; from 1966 to 1968 five Surveyor probes soft-landed there.

The first look at Mars

Mariner 4, launched in November 1964, flew past Mars on July 14, 1965, and returned the first close-up photographs of the planet: the first successful Mars mission. In 1969 Mariner 6 and Mariner 7 flew past in turn and returned hundreds of pictures. Mariner 9, launched in May 1971, entered orbit around Mars in November 1971: the first spacecraft to orbit another planet. It returned 7,329 images, more than 1,500 of which were used to build a global map of Mars.

The two Viking missions launched on August 20 and September 9, 1975. Each combined an orbiter and a lander; the landers, built with NASA’s Langley center, touched down in 1976. Bruce Murray became JPL’s director that year; William Pickering had led the laboratory for twenty-two years.

Sources: JPL, “History” (Explorer 1 on January 31, 1958 and Van Allen’s counter, the move to NASA on December 3, 1958, Mariner 2 on August 27, 1962, Ranger, Surveyor, Mariner 4 in 1965, Mariner 9 first orbiter in 1971, Viking with Langley in 1976); JPL, “NASA’s Legacy of Mars Exploration,” June 30, 1995 (Mariner 4 launched November 1964 and flyby on July 14, 1965, Mariners 6 and 7 in 1969, Mariner 9 launched May 1971, in orbit in November, 7,329 images and more than 1,500 for the map, Viking on August 20 and September 9, 1975); JPL, “NASA’s Deep Space Network Turns 60 and Prepares for the Future,” December 22, 2023 (founded 1963, Goldstone, Canberra, Madrid, equal spacing); Caltech, announcement of May 22, 2026 (managed by Caltech since 1958); JPL, “Faces of Leadership” (Pickering 1954-1976, Murray from 1976).

Chapter 3 · 1977 – 2000 Threats, losses and a small rover

After Viking, JPL explored the giant planets, but it nearly disappeared. Twenty years passed before it returned to the surface of Mars, between a dazzling success and a string of losses.

The great probes and the 1981 threat

In 1977 the two Voyager probes left for the giant planets; they would fly by Jupiter in 1979, Saturn in 1980 and 1981, Uranus in 1986 and Neptune in 1989. Yet in September 1981 NASA’s administrator threatened to end planetary exploration and close JPL. In 1982 Lew Allen, a retired Air Force general, former Air Force Chief of Staff and former director of the NSA, took charge of the laboratory; Galileo and Magellan launched under his leadership. The loss of the shuttle Challenger in 1986 delayed Galileo until 1989.

Mars Observer

On September 25, 1992, Mars Observer lifted off on a Titan III rocket. On August 21, 1993, about three days before entering orbit around Mars, the spacecraft fell silent. It was lost.

Sojourner

Under Edward Stone, director from 1991 to 2001, JPL returned to Mars. In 1997 Mars Pathfinder landed and released Sojourner, the first robotic rover to explore the planet. But the two 1998 Mars missions, Mars Climate Orbiter and Mars Polar Lander, failed; in 2000 the Mars Surveyor program they belonged to came to an end.

Sources: JPL, “History” (Voyager in 1977 and the flybys from 1979 to 1989, the September 1981 threat, Galileo delayed by Challenger, Mars Observer launched in 1992 on a Titan III and lost before orbit insertion, Sojourner first rover in 1997, the end of the Mars Surveyor program in 2000 after the two 1998 failures); JPL, “NASA’s Legacy of Mars Exploration,” June 30, 1995 (launch on September 25, 1992, loss of signal on August 21, 1993, about three days before orbit); JPL, “Faces of Leadership” (Lew Allen 1982-1990 and his background, Edward Stone 1991-2001 and Pathfinder). The 1998 missions are named after this collection’s biographies of Donna Shirley and Ashwin Vasavada.

Chapter 4 · 2001 – 2022 The age of rovers

At the turn of the century JPL made Mars a permanent worksite. In twenty years it landed four rovers and a seismic station there.

Spirit and Opportunity

Charles Elachi led the laboratory from 2001 to 2016; more than twenty missions were launched under his leadership, including the rovers Spirit, Opportunity and Curiosity. Spirit and Opportunity launched in July 2003 and landed in early 2004; Spirit would operate until 2010, Opportunity until 2018. In 2005 Mars Reconnaissance Orbiter left, whose HiRISE camera photographs the surface at high resolution.

Curiosity

On August 6, 2012, Curiosity landed in Gale Crater. It was the largest rover NASA had landed until then, lowered on cables by a “sky crane.”

InSight

On November 26, 2018, the InSight lander touched down on Mars to listen to the planet’s interior. It detected 1,319 marsquakes; the largest, caused by a meteoroid impact, unearthed boulder-size chunks of ice. Its “mole,” a self-hammering probe meant to dig about five meters down, could not gain traction in unexpectedly clumpy soil and stayed barely below the surface. In December 2022, after more than four years on Mars, its solar-charged batteries ran out of energy: the last communication came on December 15.

Sources: JPL, “Faces of Leadership” (Elachi 2001-2016, more than twenty missions, Spirit, Opportunity and Curiosity); JPL, “History” (Spirit and Opportunity launched July 2003, Spirit until 2010, Opportunity until 2018, MRO in 2005, Curiosity on August 6, 2012, InSight on November 26, 2018); JPL, “NASA Retires InSight Mars Lander Mission After Years of Science,” December 21, 2022 (1,319 quakes, the ice, the mole and the five meters, the clumpy soil, energy exhausted after more than four years, December 15); JPL, “NASA’s Perseverance Rover Completes First AI-Planned Drive on Mars,” January 30, 2026 (MRO’s HiRISE camera); this collection’s biographies of Steve Squyres, John Grotzinger and Ashwin Vasavada (2004 landings, the sky crane).

Chapter 5 · 2016 – 2028 Perseverance and the laboratory’s uncertain future

JPL sent its most autonomous rover to Mars, one that learns to find its own way. At the same time the laboratory was restructuring, and NASA put up for competition the contract that has tied it to Caltech since 1958.

Perseverance

Michael Watkins, who had spent twenty-two years at JPL, led it from 2016 to 2021. In 2019 NASA formally approved the Mars sample return project. On July 30, 2020, Perseverance launched; it is to collect samples that other missions would one day bring back to Earth. It landed in Jezero Crater on February 18, 2021. Laurie Leshin, a geochemist and space scientist, led the laboratory from 2022 to 2025.

A rover that finds its own way

On December 8 and 10, 2025, Perseverance made the first drives on Mars planned by generative artificial intelligence. The AI analyzed HiRISE images and slope maps to identify bedrock, outcrops, boulder fields and sand ripples, then laid out a route with waypoints. Before sending it, the team ran the commands through a “digital twin” of the rover, a virtual replica, checking more than 500,000 variables. The rover covered 210 meters on December 8 and 246 meters on the 10th.

On February 2, 2026, it used for the first time in regular operations a global localization system: an onboard algorithm matches its camera panoramas against orbital maps and places the rover to within about 25 centimeters, in two minutes. “This is kind of like giving the rover GPS,” says roboticist Vandi Verma. Until then, errors accumulated over long drives, sometimes more than 35 meters, forced the rover to stop and wait for instructions from Earth.

A laboratory in question

On June 2, 2025, Dave Gallagher became JPL’s eleventh director. The laboratory was going through a large-scale restructuring and cost-reduction initiatives. On May 22, 2026, Caltech announced that NASA would compete the contract for operating JPL; the current agreement ends on September 30, 2028. Caltech, which has managed the laboratory since 1958, is preparing its proposal and says it welcomes a “fair and open competition.” As many as five launches are planned for 2028. The Deep Space Network, for its part, has fourteen antennas and serves more than forty missions.

Sources: JPL, “Faces of Leadership” (Watkins 2016-2021 and his twenty-two years at JPL, Leshin 2022-2025, Gallagher eleventh director from June 2, 2025); JPL, “History” (approval of sample return in 2019, Perseverance launch on July 30, 2020); this collection’s biography of Swati Mohan (landing on February 18, 2021); JPL, “NASA’s Perseverance Rover Completes First AI-Planned Drive on Mars,” January 30, 2026 (December 8 and 10, 2025, HiRISE, waypoints, digital twin, more than 500,000 variables, 210 and 246 meters); JPL, “NASA’s Perseverance Now Autonomously Pinpoints Its Location on Mars,” February 18, 2026 (February 2, about 25 cm, two minutes, “This is kind of like giving the rover GPS,” more than 35 meters); Caltech, announcement of May 22, 2026 (competition, September 30, 2028, restructuring, “fair and open competition,” five launches in 2028); JPL, “NASA’s Deep Space Network Turns 60,” December 22, 2023 (fourteen antennas, more than forty missions).