天基遙感系統(tǒng)引領地球技術的發(fā)展

　　突破性研究是NASA努力的目標。在獲得地球和空間系統(tǒng)的基礎知識，它的使命，該組織的衛(wèi)星觀測導致在全球大氣，海洋科學研究的關系，突破海冰、陸地表面，和，當然，人類的活動（圖1）。

　　Figure 1： This photograph taken by an astronaut on the International Space Station highlights the Nevados de Chillán， a large volcanic area near the Chile-Argentina border （Courtesy of NASA）。

　　NASA’s Los Alamos Intelligence and Space Research （ISR） Division， for example， develops and applies remote sensing instrumentation， analysis， modeling， and machine learning to both national security and related sciences. Major application areas include：

　　Optical and infrared remote sensing is performed by satellite， on the ground， and in aircraft. The focus of this sensing is on modeling and analysis， radiometric calibrations， and advanced instrumentation. Thermal measurement of the earth’s surface and the use of high-resolution spectroscopy to measure trace atmospheric gases are examples.

　　A multispectral thermal imager （MTI） satellite is used for advanced multispectral thermal imaging to detect weapons and to obtain accurate and precise measurements of surface temperatures. The satellite records images in 15 bands from visible to long-wave infrared. Measurements yield information on water quality， atmospheric water vapor， aerosol content， subvisual cloud presence， and vegetative health.

　　The remote ultra-low-light-imager （RULLI） sensor system detects single photons and measures the position and absolute time of arrival of each photon for 3D scene reconstruction.

　　The Fast On-orbit Recording of Transient Events （FORTE） satellite in a circular， 800 km altitude orbit with a 70° inclination from the Earth’s equator， uses optical and RF instruments for the study of nuclear explosion events from space.

　　EdotX is a lightning location and mapping system deployed in Florida. EdotX sensors detect and sample a vertical electric field at up to 20 MHz. Eventually it will map lightning in 3D over most of the U.S. using lower-frequency signals.

　　An on-orbit electromagnetic pulse （EMP） monitoring effort provides sensor design， flight hardware， ionospheric expertise， algorithm development， system modeling， and anomaly resolution for Air Force sensors used in its GPS satellite constellation. The sensors address verification and treaty monitoring and provide insight into ionospheric， radio propagation and lightning science.