Soon, it should be possible for meteorologists to pinpoint what the weather will be like up to a week in advance. That will have a big impact on how we schedule our work and leisure time. Lockheed Martin is making weather forecasting easier and more accurate, thanks to a new sensor that can measure Earth's air temperatures from space with great precision.

The Atmospheric Infrared Sounder (AIRS) is the result of nearly ten years of research and development by Sanders' Infrared Imaging Systems in Lexington, Mass., under contract to NASA's Jet Propulsion Laboratory. The 390-pound instrument is scheduled for launch in December 2000 aboard NASA's AQUA spacecraft, which is an essential element of its Earth Observing System (EOS) mission.

A major advance in satellite remote sensing technology, AIRS promises to provide NASA and the world's scientific community with new and highly accurate data about the atmosphere, land, and oceans for use in climate studies and improved weather predictions.

"The AIRS instrument will have a profound impact on weather forecasting for everyone. For example, with accurate seasonal rain prediction, we can predict and manage our water resources better, even before the rain actually hits the ground," said Dr. Moustafa Chahine, AIRS science team leader and chief scientist at NASA's Jet Propulsion Laboratory.

"AIRS will be able to read atmospheric temperatures to within one degree centigrade in one kilometer layers of altitude in the Earth's lower atmosphere. That degree of accuracy will allow weather forecasters to significantly improve and extend their weather predictions to seven-day forecasts."

Continuously measuring more than two thousand discrete infrared colors in the 3.7 to 15.4 micrometer range, AIRS' high resolution spectrometer will precisely sample the Earth's atmosphere from the ground up to as high as 30 miles.

The system determines air temperatures and moisture profiles by observing the infrared signatures of carbon dioxide and water vapor.

Because gases such as carbon dioxide, water vapor, ozone, and methane absorb most strongly within specific wavelengths of infrared energy, and because this absorption increases as one looks deeper into the atmosphere from space, AIRS can "see" exact environmental conditions at different levels of the atmosphere.

The very high spectral resolution -- with data collected in many very narrow wavelength bands -- not only allows scientists to determine the temperature and humidity at specific altitudes, but also derives an accurate vertical profile of the state of the lower atmosphere on a global scale.

>From these measurements, climate experts will be able to study variations in the Earth's water and energy cycles. AIRS will provide new information about cloud types and cloud cover, and show how they are affected by changes in temperature, evaporation and condensation rates, and atmospheric circulation patterns.

The information will also shed more light on how greenhouse gases such as carbon dioxide, water vapor, industrial pollutants and aerosols are trapped in Earth's atmosphere.

The AIRS instrument consists of more than 40,000 space qualified components, and uses a high-resolution array grating spectrometer, which is cooled to minus 120 degrees centigrade.

Its advanced focal plane -- which is cooled to minus 215 degrees centigrade using specially developed cryogenic refrigerator technology -- achieves both high performance and long usable life expectancy.

AIRS incorporates state-of-the-art developments in other areas as well. Paul Morse, Sanders' AIRS Program Technical Director at the Lexington facility, said AIRS represents a "major advance in satellite-based remote sensing technology.

It required simultaneous development and integration of five new technologies -- multiband focal plane architecture, long wavelength photovoltaic detectors/readouts, custom optical filters, long-life, low vibration mechanical coolers, and high-efficiency coarse diffraction grating optics -- none of which were available" in the early 1990s.

These technologies were all demonstrated through a rigorous test program, Morse said, including thermal vacuum testing, environmental qualification, and a full range of spatial, spectral, and radiometric calibrations.

The AIRS instrument was delivered to NASA in November 1999, and has since undergone integration and mounting onto the AQUA spacecraft at the TRW Corporation's facilities in Redondo Beach, Calif. It will be one of six major instruments to ride on the satellite.

AQUA is the second of three spacecraft in NASA's Earth Observing System (EOS) series. Scheduled to last for at least six years, the prime objective of the EOS mission is to make long-term observations to gain a better understanding of the complex processes affecting global environmental changes.

Through EOS, scientists hope to gain significantly more insight into such threatening phenomena as ozone depletion, deforestation, desertification, and the greenhouse effect -- and from that, suggest potential long-term remedies.

In a note of appreciation to the AIRS team at Lockheed Martin, Dr. Chahine wrote that, "AIRS is like a great violin, a Stradivarius. It is a joy to have it � you have made my dream of twenty years and that of my colleagues finally come true."

Sanders is an operating company of the Lockheed Martin Corporation, and a major producer of aircraft self-protection systems and tactical surveillance and intelligence systems for all branches of the armed forces.