Studying Earth in the New Millennium: NASA Jet Propulsion Laboratory's Contributions to Earth Science and Applications Space Agencies

The NASA Jet Propulsion Laboratory (JPL) is a national research facility that carries out cuttingedge earth science missions. JPL developed the first U.S. Earth-orbiting science spacecraft and is a pioneer in the use of remote sensing for science of the oceans, atmosphere, and solid earth. Explorer I was the first U.S. Earth-orbiting spacecraft. It followed the Soviet Sputniks 1 and 2 but carried James Van Allen's Geiger counter, which upended space physics with the discovery of the radiation belts now named for him [1]. Explorer I also carried a micrometeoroid detector. JPL developed atmospheric temperature instruments for the Nimbus series of weather satellites, built microwave and infrared instruments to help gain an understanding of stratospheric ozone depletion, ocean circulation, and surface winds, and flew Seasat, which carried the first civilian synthetic aperture radar. This article gives a general overview of recent, current, and near-future earth science missions led by JPL, highlighting a few of the many measurements that are transforming our understanding of the processes governing the Earth's atmosphere, oceans, land surfaces, and climate.