JPL at 90: From a Riverbed Rocket Test to Voyager and Mars

Four tries on Halloween

The group grew up around Frank Malina, a graduate student at GALCIT, the Caltech aeronautics laboratory that Theodore von Kármán directed. Jack Parsons, a self-taught explosives expert, and Ed Forman, a skilled mechanic, built rockets of their own; the three were the core of what Caltech would later nickname the Suicide Squad. Von Kármán insisted that they measure how a motor performed instead of just launching rockets, so they built an instrumented test motor, much of it from junkyard parts, that burned methyl alcohol with oxygen.

They went to the Arroyo Seco because Caltech did not want fires and explosions on campus. Three times the powder fuse blew out before it could light the motor. On the fourth try the motor ignited, and so did the oxygen hose, which whipped across the ground in flames as the team ran. Sandbags shielded the team; no one was hurt. JPL's account says the motor ran about three seconds; no thrust was recorded. With a spark plug in place of the fuse, the team got its first thrust measurements on Nov. 15.

From Army rockets to a NASA lab

In 1939 the work found a customer: at the request of the chief of the Army Air Corps, a National Academy of Sciences committee funded work on rockets to help planes take off from short runways. In 1943, in a proposal to the Army for a U.S. answer to Germany's V-2 missile, the team first called itself the Jet Propulsion Laboratory.

So when did JPL begin? In 1936 there was no laboratory and no name, only a student project. The name first appeared in 1943 and became official in June 1944, when the Army's Ordnance Department took over the funding. JPL dates itself from the first test.

On Jan. 31, 1958 (already Feb. 1 in UTC), an Army Jupiter-C rocket launched Explorer 1, the first U.S. satellite, which JPL designed, built and operated. Its cosmic-ray detector, from James Van Allen, counted fewer particles than expected. Van Allen read that as a sign the instrument was swamped by trapped radiation; a satellite launched two months later confirmed the belts now named after him. On Dec. 3, 1958, JPL moved from the Army to the new civilian agency NASA. Caltech still runs it for NASA.

A lab that goes first

Mariner 2 flew past Venus on Dec. 14, 1962, the first spacecraft to fly by another planet and send back data. Voyager 2, launched in August 1977, became the first probe to visit all four giant planets; its planetary tour ended at Neptune in 1989. On Aug. 25, 2012, its twin Voyager 1 became the first spacecraft to leave the heliosphere, the bubble the solar wind inflates around the Sun and its planets.

Mars Pathfinder touched down July 4, 1997, and released Sojourner, the first rover to drive on Mars. In 2021 the Ingenuity helicopter made the first powered, controlled flight on another planet and flew 72 times in all. Europa Clipper, launched Oct. 14, 2024, is due at Jupiter in April 2030 to study Europa, a moon thought to hide a salty ocean under its ice.

What comes next

On Nov. 18, 2026, Voyager 1 is expected to reach one light-day from Earth, about 16 billion miles (26 billion kilometers): a command sent that day takes 24 hours to arrive. No optical telescope can see the spacecraft; the only link is through the large antennas of NASA's Deep Space Network, which JPL began building in 1958 and formally set up in 1963.

Next for JPL: SkyFall, aiming to launch in 2028 and drop three helicopters during descent to Mars to map buried ice; MoonFall, rocket-powered drones to land near the Moon's south pole; SunRISE, six small satellites set to launch in 2027 and fly in formation as one radio antenna to study the Sun; and NEO Surveyor, an asteroid-hunting space telescope.

The anniversary comes at a hard time: after two rounds of layoffs in 2024, JPL cut about 550 more jobs in October 2025, citing budget pressures.