TRW delivers first CERES instrument to NASA; CERES to study role of clouds and radiation on environment.

REDONDO BEACH, Calif.--(BUSINESS WIRE)--Oct. 17, 1995--TRW Inc. has delivered the first Clouds and the Earth's Radiant Energy System (CERES) instrument to NASA Langley Research Center.

CERES will be integrated and tested on the Tropical Rainfall Measuring Mission (TRMM) spacecraft at the NASA Goddard Space Flight Center. TRMM is scheduled for launch in August 1997.

This unit is the first of six CERES instruments TRW is developing for NASA. CERES will measure reflected solar radiation and emitted thermal radiation over the Earth's surface to determine the influence of clouds on the Earth's temperature.

Small changes in the amount of solar radiation absorbed or reflected can cause significant temperature changes. And without clouds, the planet could be 20 degrees hotter; yet complete cloud covering might precipitate an ice age.

``Clouds are one of the largest sources of climatic uncertainty,'' said Steve Carman, CERES program manager at TRW's Space & Electronics Group in Redondo Beach. ``We believe the data gathered by CERES will help scientists build accurate models to forecast long-range climatic trends and, in particular, to better understand the effects of clouds on the global climate.''

As part of NASA's Earth Observing System (EOS) program, CERES and a variety of other science instruments will be flown on several Earth-monitoring spacecraft launched by the United States and Japan. These spacecraft include TRMM, EOS AM and EOS PM. The goal of EOS is to better understand the interactions of the Earth's land masses, oceans and atmosphere, and how the Earth as a system is changing.

CERES is a scanning broadband radiometer that measures the reflected sunlight and emitted thermal energy from the surface of the Earth and the atmosphere. The radiometer is made up of three sensors, each with its own telescope mounted on a gimbaled platform that scans across the Earth in a 6.6-second cycle.

The total channel sensor measures all radiation from near- ultraviolet to far-infrared. The shortwave channel sensor monitors reflected solar radiation.

The third sensor, a longwave channel sensor, monitors emitted thermal energy between eight and 12 microns. It allows scientists to measure more accurately the radiation emitted from the surface of the Earth, a key parameter in determining the ``greenhouse'' effects of the gases in the atmosphere.

The predecessor to CERES, the Earth Radiation Budget Experiment (ERBE), showed that clouds are the dominant influence on the energy balance of the Earth.

Six ERBE instruments built by TRW, three nonscanning and three scanning radiometers, were launched in pairs on three satellites between 1984 and 1986. The ERBE scanners provided more than five years of data, well beyond their one-year design life.

Measurements made by CERES during its five-year mission life are required to be accurate to within 0.5 percent, which is more stringent than the ERBE requirement. To meet this requirement, CERES' sensors have been precisely calibrated using standards from the National Institute of Standards and Technology at TRW's absolute radiometric calibration facility.

In tests this summer, the instrument demonstrated accuracy better than specifications.

CERES data will be combined with data from supporting imaging instruments that identify cloud conditions. NASA Langley is responsible for CERES data reduction. The CERES science investigation will be conducted by an international team of scientists, led by Principal Investigator Dr. Bruce Barkstrom of NASA Langley Research Center.

TRW is delivering six CERES instruments to NASA under an 11-year contract scheduled for conclusion in 2001. TRW was awarded a Phase I study for CERES in 1990 and a Phase II develop-and-build contract in 1991.

TRW's CERES team members include Schaeffer Magnetics Inc., Chatsworth, Calif., which provides the CERES biaxial scan assembly, and Servo Corporation of America, Hicksville, N.Y., which provides the CERES sensor assemblies.

TRW Space & Electronics Group has built more than 185 communications, scientific and defense spacecraft; produced, integrated and tested more than 130 payloads; developed more than 200 advanced space instruments; and integrated some 550 experiments into spacecraft.

It is an operating unit of TRW Inc., which provides advanced- technology products and services for the automotive, space and defense, and information markets worldwide. TRW Inc.'s 1994 sales totaled $9 billion.

CONTACT: TRW Inc., Redondo Beach

Brooks McKinney, 310/814-8177