Interstellar probes. Lunar drones. Helicopters on Mars.

When a group of Caltech graduate students and enthusiasts began conducting rocket-propulsion tests in Pasadena’s Arroyo Seco on Oct. 31, 1936, they had no idea that their work marked the inception of the Jet Propulsion Laboratory. Ninety years later, the lab, now managed by Caltech for NASA, isn’t only celebrating the long line of historic firsts accomplished here; it’s paving the way for many to come.

Initially a contractor for the U.S. Army, JPL launched America’s first satellite, Explorer 1 in 1958. But rather than just orbiting Earth like the Soviet Union’s Sputnik, Explorer 1 became the first spacecraft to conduct science, thanks to an onboard Geiger counter that discovered the protective radiation belts encircling Earth.

The lab joined part of the newly formed NASA that same year. Within six years, in 1964, JPL sent the first U.S. mission to the Moon, Ranger 7 .…