The Jet Propulsion Laboratory has awarded Loral Infrared & Imaging Systems a $145 million contract to design and build the Atmospheric Infrared Sounder (AIRS) instrument to be flown on the first of NASA's Earth Observing System (EOS) satellites.

Under terms of the contract, the company, a division of the Loral Corp. based in Lexington, Mass., will design, develop and produce the first atmospheric sounder for delivery to JPL in 1996.

AIRS will be a global thermometer in space and will be one of the world's premier monitors to study the effects of increased "greenhouse" gases in the Earth's atmosphere when the EOS-A series is launched. The satellites are tentatively scheduled for flight beginning in 1998.

The space-borne instrument will measure atmospheric temperature profiles with an accuracy of 1 degree Centigrade and provide data on atmospheric water vapor, cloud cover, and sea- and land-surface temperatures. The AIRS investigation will be led by JPL Chief Scientist Dr. Moustafa Chahine.

AIRS is one of several instruments targeted for the first of three satellites in the EOS-A series of Earth-observing platforms. The satellites will use a polar orbit to make global measurements of Earth's oceans, land surface, and lower and upper atmospheres.

"The primary goal of the EOS-A satellites is to study the effects of potential global warming by conducting long-term research into the key parameters of the Earth's surface and atmosphere," said Dr. Charles Elachi, director of JPL's Office of Space Science and Instruments, which will oversee development of the instrument.

"Global changes are very complicated and require long-term monitoring," he said. "The EOS-A series will help determine the causes and extent of global climate changes through a program of long-term observations."

The AIRS sounder will operate continuously for five years, providing new and more accurate data about the Earth's atmosphere, surface and oceans for climate studies and weather predictions. Among the most important discoveries to be gleaned from infrared observations are humidity profiles and the temperature of land, oceans and the atmosphere.

The sounders are based on Loral's advanced mercury cadmium telluride focal plane technology. The sounders measure temperatures by observing 3,600 wavelengths in the infrared spectrum via spectral dispersion -- such as in a prism -- across high-density linear sensors. Ground-processing computer algorithms convert this data into global profiles of air and surface temperature.

EOS is the centerpiece of NASA's "Mission to Planet Earth," a global-scale research program that will study the Earth as an integrated environmental system, focusing on the interactions of the atmosphere, oceans, land surfaces and biosphere.

"Mission to Planet Earth" is NASA's contribution to the U.S. Global Change Research Program, a multi-agency federal program to observe the Earth, improve understanding of natural and human-induced global change and develop better models and predictive capabilities for interpreting environmental changes.

The JPL EOS-A satellite instruments are being developed under the auspices of the Laboratory's Office of Space Science and Instruments.

The EOS project is managed by the Goddard Space Flight Center in Greenbelt, Md., for NASA's Office of Space Science and Applications. Overall program management is an international effort involving NASA, the European Space Agency, Japan and Canada.

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