EuRAD01 : EuRAD Opening Session

摘要

Radar instruments play a critical role in NASA's planetary, cometary, and Earth observing missions. Sometimes they guide space crafts to the surface of another planet (such as Mars) or a comet and some other times they are used for answering fundamental scientific questions by exploring cometary and planetary bodies, including our own Earth. Until recently, the majority of NASA's radar instruments were below 100 GHz. However, in recent years, there has been a lot of interest in using millimeter-wave and terahertz radars to answer critical scientific questions. One such instrument developed by us is a 183 GHz (G-Band) differential absorption radar providing a new measurement capability of simultaneously measuring water vapor and ice content in clouds in Earth's atmosphere with high precision and spatial resolution. Profiling of water vapor within clouds is a critical requirement to address the key unsolved science questions regarding the processes regulating cloud lifecycle and the transport of water vapor by convection. Another instrument we developed is a 90 GHz (W-Band) frequency modulated continuous wave (FMCW) radar for understanding the origin, dynamics, and evolution of jets from a comet. When deployed, this will provide clues to the formation of comets and therefore the early stages of the Solar System. The same W-band radar is also being planned for investigating plumes on icy moons, such as Europa and Enceladus, which will shed light on subsurface processes and structure on these potentially life-harboring bodies. We are also building a revolutionary in situ radar instrument for short-range mapping of near-surface atmospheric water vapor on Mars. This highly compact and low-power differential absorption radar operates near the 557 GHz water absorption line to measure absolute humidity along its beam path with as good as few-ppm level accuracy. This instrument allows us, for the first time, range-resolved absolute humidity estimates on Martian surface. Apart from science instrument radars, we also developed a 670 GHz FMCW radar for imaging at stand-off distances for security applications.