The Jet Propulsion Laboratory (JPL) is an establishment in Pasadena, California, operated by the California Institute of Technology for NASA, which plays a major role in the development, operation, and tracking of US interplanetary space probes. JPL has responsibility for the Deep Space Network and has managed the Viking, Voyager, Galileo, and Mars Pathfinder missions, among many others. JPL was founded by Theodore von Kármán and Frank Malina in 1944 and was a focal point of American rocket development in World War II. In 1958 it became part of NASA and provided America's first successful Earth satellite, Explorer 1.

Among JPL's current major active projects are the Mars Science Laboratory mission (which includes the Curiosity rover), the Cassini-Huygens mission orbiting Saturn, the Mars Exploration Rovers (Spirit and Opportunity), the Mars Reconnaissance Orbiter, the Dawn mission to Ceres and Vesta, the Juno spacecraft en route to Jupiter, the Gravity Recovery and Interior Laboratory (GRAIL) mission to the Moon, the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray telescope, and the Spitzer Space Telescope.