15 December 1999

NASA'S GIANT TERRA SATELLITE TO LIFT OFF WITH U.K. TECHNOLOGY

The $1.3 billion TERRA is considered to be the flagship of NASA's long term Earth Observing System programme. With major contributions from the U.S., Japan and Canada, the polar-orbiting spacecraft is designed to spend the next six years studying our planet's land surface, oceans, clouds and atmosphere.

Under the leadership of Dr. Guy Peskett, a team from the Dept. of Atmospheric Physics, Clarendon Laboratory, Oxford University, has helped to build the Measurement Of Pollution In The Troposphere (MOPITT) instrument, one of the scientific experiments on board this major mission.

"This is the first attempt to carry out long-term measurements from space of pollutants in the lower atmosphere, " said Dr. Peskett, a Co-Investigator on MOPITT.

MOPITT, CARBON MONOXIDE AND METHANE

Concentrations of these gases can be altered by both natural phenomena and human activity, such as cultivation of rice paddies, or burning of the rainforests.

Although they are not major constituents of the atmosphere, they are important players in the chemistry of our planet's atmosphere.

Carbon monoxide is interesting because of its potential for showing atmospheric motions as well as providing information about chemical reactions in the troposphere.

Methane is an important greenhouse gas, which is extremely efficient at trapping heat. Even a small rise in its atmospheric concentration could cause temperatures to rise, causing ice sheets to melt and increases in sea level.

The international MOPITT science team, which includes scientists from Canada, the United States and the United Kingdom, will be studying the global data and using it to help develop mathematical models of the chemical processes taking place in the troposphere.

MOPITT measures the concentrations of CO and CH4 molecules in the troposphere by detecting the infrared light they emit. It does this through a technique called correlation spectroscopy.

Infrared light emitted by the atmosphere enters a telescope and is sent through a cell which is filled with the gas to be measured (either carbon monoxide or methane). So light from atmospheric CO is partially absorbed as it passes through a cell containing CO, while light emitted by other atmospheric gases is not affected.

By varying the amount of CO in the cell (or changing its length), the light emitted by the atmospheric CO can be 'labelled' with an amplitude modulation. It then falls onto a detector which converts the light signal into an electrical signal. The modulated signal of the CO can then be picked out from the out put of the detector by the instrument's signal processing electronics.

In this way, MOPITT acts as an optical filter, selecting only the light emitted by the atmospheric CO. The same method is used to measure the infrared signal from atmospheric methane. Using existing knowledge of the molecules' spectroscopic properties, the distributions of CO and CH4 in the atmosphere can then be computed.

Continuous measurements will be sent back as the TERRA satellite moves along its orbit. Previous measurements of pollutants from space have always looked sideways at the upper atmosphere. MOPITT will look straight down at the planet, continuously scanning a swath about 600km wide.

This has the advantages of increasing the spatial coverage of the instrument and improving the chance of finding gaps in the clouds. Unfortunately, it means that MOPITT also "sees" the surface of the planet and so picks up unwanted background radiation.

"This makes the measurements extremely difficult," said Dr. Peskett.

"However, if all goes well, we hope to be able to see a lot of detail, such as plumes of pollution down wind of cities, as well as producing global maps of carbon monoxide and methane levels every four days," he added.

MOPITT's performance is enhanced by cooling its detectors and filters to 100K (-173C). This temperature is obtained by using Stirling Cycle coolers developed at Oxford University and supplied by British Aerospace (now Matra Marconi Space, Stevenage, U.K.). The use of such mechanical coolers, rather than stored supercooled gas or radiative cooling, allows the instruments to operate over a much longer lifetime.

NOTES

It carries a payload of five state-of-the-art sensors that will study the interactions among the Earth's atmosphere, lands, oceans, life, and radiant energy (heat and light).

Roughly the size of a small coach, TERRA is currently scheduled to be launched by an Atlas-Centaur rocket from Vandenberg Air Force Base, California on the evening of 16 December 1999 (U.K time). It will be placed into a 705 km, sun-synchronous orbit. This means it always crosses the equator from north to south at 10:30 am local time, when cloud cover is minimal and its view of the surface is least obstructed.

Since the satellite's orbit will be roughly perpendicular to the direction of Earth's spin, swaths observed during each overpass can be compiled into images covering the entire planet. Over time, these global images will enable scientists to investigate the causes and effects of global climate change.

The sensors on Terra will not actively scan the surface (such as with laser beams or radar pulses). Instead, they work much like a camera, detecting sunlight reflected by clouds and the Earth's surface, and the heat which is emitted from the atmosphere and the surface.

This radiant energy is passed through gas correlation cells and is then focused onto cooled detectors. These are sensitive to selected regions of the electromagnetic spectrum, ranging from visible light to heat. The information produced by these detectors will then be transmitted back to Earth and processed by computers into images.

The principal scientific investigator for MOPITT is Prof. James R. Drummond, Department of Physics, University of Toronto, Ontario, CANADA M5S 1A7.

Detailed information on Terra is available via the Internet at:
http://terra.nasa.gov

The Mopitt home page is at:
http://www.atmosp.physics.utoronto.ca/mopitt

Lockheed Martin Missiles & Space

Lockheed Martin Terra Earth Observing System spacecraft readied for December launch

"It is very satisfying to have the Terra spacecraft here at Vandenberg ready for launch," said Mike Kavka, Lockheed Martin Terra program manager at Valley Forge. "Our workforce at the Delaware Valley facilities of Missiles & Space have been the premier builders of Earth-remote sensing spacecraft since the very beginning of the Space Age. So it is with particular pride that we get ready to launch Terra, the final remote sensing satellite built there. As we consolidate our satellite operations in Sunnyvale, we will not forget the significant role our Delaware Valley employees played in monitoring and mapping our planet."

The launch of Terra will mark the beginning of a comprehensive study of clouds, water vapor, small particles in the atmosphere (called "aerosol" particles), trace gases, land surface and oceanic properties, as well as the interaction between them and their effect on the Earth's energy budget and climate. Moreover, Terra will observe changes in the Earth's radiation energy budget -- which is the amount of incoming energy from the sun minus outgoing energy from reflected sunlight and emitted heat. If we are to succeed in building predictive computermodels of these complex interactions, we must clearly comprehend global climatic processes and parameters. The Terra team estimates that it will complete the first Earth system models within five years after launch.

Terra is a joint project between the United States, Japan, and Canada. The U.S. provided the spacecraft and three instruments developed by NASA Field Centers -- the Clouds and the Earth's Radiant Energy System (CERES), the Multi-angle Imaging SpectroRadiometer (MISR), and the Moderate-resolution Imaging Spectroradiometer (MODIS). Langley Research Center, Hampton, Va. provided two CERES units, the Jet Propulsion Laboratory, Pasadena, Calif., provided MISR, and Goddard Space Flight Center provided the MODIS instrument. The Japanese Ministry of International Trade and Industry provided the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The Canadian Space Agency provided an instrument called Measurements of Pollution In The Troposphere (MOPITT).

The spacecraft instruments comprise eight separate sensors with a range of resolutions that will gather data on clouds, aerosols, and the Earth's radiative balance, and measure surface properties and their interaction with the atmosphere:

• CERES, the Clouds and Earth's Radiant Energy System, will measure Earth's radiation budget and atmospheric radiation from the top of the atmosphere using a broadband scanning radiometer with bolometers detectors.
  
• MISR, the Multi-angle Imaging Spectro-Radiometer, will measures top-of-atmosphere, cloud and surface angular reflectance functions, and measure surface BRDF, aerosol, and vegetation properties using four spectral bands in each of nine imaging cameras oriented at different angles.
  
• MODIS, the Moderate Resolution Imaging Spectro-Radiometer, will measure biological and physical processes on land and the ocean using a cross-track scanning multi-spectral radiometer with 36 spectral bands from visible to thermal infrared
  
• ASTER, the Advanced Spacebourne Thermal Emission and Reflection Radiometer, will provide high-resolution images of the land surface, water, ice, and clouds using three separate sensor subsystems covering 14 multi-spectral bands from visible to thermal infrared.
  
• MOPITT, the Measurements of Pollution in the Troposphere, will measure carbon monoxide and methane in the troposphere using correlation spectroscopy with pressure modulated and length modulated gas cells.
  

The science objectives of the Terra mission are to begin the continuous, long-term, calibrated measurements of global processes. Terra scientists seek to improve their understanding of the role of clouds and aerosols in Earth's radiation budget. They hope to discover the sources and sinks of energy, water, and carbon in the terrestrial biosphere. They want to better understand terrestrial ecosystem dynamics and their links to climate, sea surface temperature and ocean primary productivity.

Terra and subsequent EOS missions form the core of NASA's Earth Science Enterprise. The goal of the enterprise is to turn NASA's space-based observing technology and scientific expertise to the study of the planet Earth as an integrated system of land, ocean, atmosphere, ice, and biological processes. By viewing the Earth from space, scientists can begin to understand how the systems work and how they interact. Questions posed and answers found in this grand scientific inquiry will likely yield knowledge of substantial practical value to society in weather and climate forecasting, in agriculture, in natural resource management, in urban and regional planning, and elsewhere.

Lockheed Martin Missiles & Space, based in Sunnyvale, CA, is a leading supplier of satellites and space systems to military, civil government and commercial communications organizations around the world. These spacecraft and systems have enhanced military and commercial communications; provided new and timely remote-sensing information; and furnished new data for thousands of scientists studying our planet and the universe.

High and low resolution images of the Terra spacecraft.

Canadian Space Agency

Canadian MOPITT Instrument to Launch on Terra Satellite

The CSA provided MOPITT to NASA's Terra satellite mission and will contribute to on-orbit mission operations and data analysis. MOPITT is an infrared gas-correlation instrument that will contribute to Terra's mission of observing the Earth from the unique vantage point of space by taking global measurements of carbon monoxide and methane in the troposphere. The MOPITT Principal Investigator is Prof. James Drummond of the University of Toronto and COM DEV International of Cambridge, Ontario, built the MOPITT instrument, both under contract to the Canadian Space Agency.

A backgrounder on the MOPITT instrument can be accessed at:
http://www.science.sp-agency.ca/J1-MOPITT(Eng).htm

B-rolls with animation of the operation of the Canadian MOPITT instrument, and taped comments by Dr. Drummond are also available by contacting the number below.

Updates on the launch will be posted on the Canadian Space Agency Web site.

NASA TELEVISION COVERAGE

NASA Television is carried on GE-2, transponder 9C located at 85 degrees West longitude. Audio only will be available on the "V" circuits, which may be reached by dialing (407) 867-1220, 1240, 1260, 7135, 4003, 4920.

Langley Research Center
Hampton, VA

10 Dec. 1999

NASA LANGLEY CERES INSTRUMENTS TO LAUNCH DEC. 16

Langley Contributes Instruments to Complete 'Global Picture' of Earth

CERES is one of five instruments that will fly aboard Terra and contribute to the comprehensive look at the Earth system. Terra is a joint Earth Observing System venture between the United States, Japan, and Canada. Terra, with CERES, will collect for the first time ever, simultaneous global information about clouds, water vapor, and the Earth's radiation balance. This is the energy that reaches the Earth from the Sun and the energy radiated from Earth into space.

"We are looking for a whole new level of accuracy in these radiation energy flows," said Langley's Dr. Bruce Wielicki, one of the lead scientists for the CERES project. "To achieve this, we will fly two instruments on Terra. One will scan and immediately observe the entire Earth from equator to pole, and the second one will scan in angles to cover the hemisphere of radiation flow, which changes dramatically from upward direction to the limb, or edge, of the Earth."

Solar and Earth-emitted energy data and cloud measurements taken by CERES will be used to provide a critical check for the models used by scientists to simulate global climate and predict the effects of global warming, according to lead scientists Wielicki and Dr. Bruce Barkstrom.

Some Terra products will be produced by combining data from more than one instrument, allowing the instrument teams to develop broad science approaches to specific problems.

"The Terra observatory brings entirely new capabilities by combining multiple instruments looking at the Earth at the same place and time," said Wielicki. "While CERES measures the solar energy reflected back to space and Earth thermal energy emitted to space, the other instruments will bring new, more accurate measurements of the clouds and aerosols that cause changes in the energy flow, allowing for new studies of cause and effect in the climate system."

Analysis of the CERES data will lead to a better understanding of the role of clouds and the energy cycle in global climate change. The CERES instruments will extend the data collection begun in the 1980s by NASA's Earth Radiation Budget Satellite (ERBS).

"We are very excited to continue the climate record started with ERBS, incredibly still alive after fifteen years in space," continued Wielicki. "This climate record is a critical measure of the amount of radiation energy flowing in and out of the planet and is likely to change as the climate changes. We are also very interested in studying the changes which have occurred during and since the recent 1997/1998 major El Niņo."

CERES data from a NASA satellite launched in November 1997, the Tropical Rainfall Measuring Mission (TRMM), is already helping scientists understand the flow of radiation in the tropics, but the new instruments on Terra will extend these observations to cover the entire globe.

NASA Langley Research Center, Hampton, Va., designed and manages the two CERES instruments that will fly aboard Terra. The CERES instruments were built by the TRW Corp., Redondo Beach, Calif.

NASA Goddard Space Flight Center, Greenbelt, Md., is responsible for the development and launch of the satellite, and for the controlling the ground operations system. The Terra Project Office, located at NASA Goddard, manages the satellite for NASA's Office of Earth Science in Washington, D.C.

Follow-on CERES instruments are planned which will create a continuous 15-year history of highly accurate radiation and cloud data for climate analyses.

Terra is scheduled for launch from Vandenberg Air Force Base, Calif., on Dec. 16. The 25-minute launch window opens at 1:33 p.m. EST (10:33 a.m. PST). Separation of the spacecraft from its launch vehicle will occur about 14 minutes after launch.

NASA Television will broadcast the launch and concurrent science briefing live. The briefing will feature a question-and-answer session for media from participating NASA centers. NASA TV is available on GE-2, transponder 9C (C-Band), located at 85 degrees West longitude, vertical polarization with a frequency of 3880 MHz and audio of 6.8 MHz.

CERES information.

Terra web site.

Images supporting this release.

JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

December 9, 1999

TERRA EARTH SCIENCE MISSION READY FOR LAUNCH DEC. 16

Terra, managed by NASA's Goddard Space Flight Center, Greenbelt, Md., is the NASA flagship mission in a new series of spacecraft dedicated to the U.S. Global Change Research Program. Terra carries five sophisticated sets of instruments with measurement and accuracy capabilities never before flown. See http://eos-am.gsfc.nasa.gov for details on the mission.

Terra takes a global approach to data collection that will enable scientists to study the interaction among the four spheres of the Earth system -- the oceans, lands, atmosphere and biosphere. Long-term weather and climate prediction requires the collection of better data over longer periods to understand the links between these spheres.

Among the instruments are two managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif.:

• The JPL-built Multi-angle Imaging Spectro-Radiometer (MISR) will improve our understanding of the Earth's ecology and climate by studying how changes in the amounts, types, and distribution of clouds, airborne particulates, and surface covers can affect our climate. For more information, go to http://www-misr.jpl.nasa.gov .
• The Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER), a joint U.S.-Japanese instrument, will produce detailed global, regional and local image maps of land surface temperature, reflectance and elevation and other characteristics. ASTER is the only high-spatial-resolution instrument on Terra, and the instrument's ability to serve as a "zoom lens" for the other instruments will be particularly important for land studies, detecting surface changes, and for calibrating instruments. See http://asterweb.jpl.nasa.gov for more information.

JPL is a division of the California Institute of Technology, Pasadena, Calif.

NASA Headquarters, Washington, D.C
Goddard Space Flight Center, Greenbelt, Md.

November 23, 1999

TERRA SPACECRAFT TO LEAD THE WAY

Terra begins a new generation of Earth science - one that studies the Earth's land, oceans, air, ice and life as a total global system. Terra will carry a complement of five synergistic state-of-the-art instruments. Researchers now recognize that the Earth - land, oceans, life, and atmosphere - operates as a system - one part impacting the other. EOS will help us to understand how the complex coupled Earth system of air, land, water and life is linked. A series of 10 spacecraft, known as the first EOS series, are scheduled for launch into the next decade.

"After years of anxious anticipation we're extremely excited about this mission," said Dr. Ghassem Asrar, associate administrator, NASA's Earth Science Enterprise. "The Terra mission has nearly unlimited potential to improve scientific understanding of global climate change."

The EOS series spacecraft are the cornerstone of NASA's Earth Science Enterprise, a long-term coordinated research effort to study the Earth as a global system and the effects of natural and human-induced changes on the global environment. Terra will use this unique perspective from space to observe the Earth's continents, oceans, and atmosphere with measurement accuracy and capability never before flown. This approach enables scientists to study the interactions among these three components of the Earth system, which determine the cycling of water and nutrients on Earth.

"Terra will simultaneously study clouds, water vapor, aerosol particles, trace gases, terrestrial and oceanic properties, the interaction between them and their effect on atmospheric radiation and climate," said Dr. Yoram Kaufman, Terra project scientist from Goddard Space Flight Center, Greenbelt, Md. "Moreover, Terra will observe changes in Earth's radiation budget (a measurement of all the inputs and outputs of the Earth's radiative energy), together with measurements of changes in land/ocean surface and interaction with the atmosphere through exchanges of energy, carbon, and water. Clearly comprehending these interactive processes is essential to understanding global climate change," he said.

A polar-orbiting spacecraft, Terra is scheduled for launch aboard an Atlas-Centaur IIAS expendable launch vehicle from Vandenberg Air Force Base, Calif. The 25-minute launch window opens at 1:33 p.m. EST (10:33 a.m. PST). Separation of the spacecraft from its launch vehicle will occur about 14 minutes after launch.

Once in its final orbital position, the satellite will orbit the Earth at an altitude of approximately 438 miles (705 kilometers) with a Sun-synchronous 98-degree inclination and descend across the equator at 10:30 a.m. Because Terra emphasizes observations of terrestrial surface features, its orbit is designed to cross the equator at this time when cloud cover, which obscures the land surface, is at its daily minimum. The orbit will be adjusted so that it covers the complete Earth every 16 days. This orbit will be maintained with periodic adjustments during the six-year life of the mission.

The spacecraft was built by Lockheed Martin Missiles and Space in Valley Forge, Pa. The five instruments onboard Terra include the Clouds and the Earth's Radiant Energy System (CERES), the Multi-angle Imaging SpectroRadiometer (MISR), the Moderate-Resolution Imaging Spectroradiometer (MODIS), the Measurements of Pollution in The Troposphere (MOPITT), and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument.

The CERES instruments, provided by NASA's Langley Research Center, Hampton, Va., and built by TRW, Redondo Beach, Calif., perform measurements of the Earth's "radiation budget," the process that maintains a balance between the energy that reaches the Earth from the sun, and the energy that goes from Earth back out to space. The critical components that affect the Earth's energy balance are the planet's surface, atmosphere, aerosols, and clouds.

MISR, built and provided by NASA's Jet Propulsion Laboratory, Pasadena, Calif., will measure the variation of surface and cloud properties, and particles in the atmosphere, with cameras pointed in nine simultaneous different viewing directions. MISR will monitor monthly, seasonal, and long-term interactions between sunlight and these components of Earth's environment. Over a seven-minute period, points on the Earth within a 224 mile (360 kilometer) wide swath will be observed successively at all nine angles.

The Moderate-Resolution Imaging Spectroradiometer (MODIS), provided by Goddard., and built by the Raytheon (formerly Hughes) Santa Barbara Remote Sensing, Santa Barbara, Calif., will measure the atmosphere, land and ocean processes, (including surface temperature of both the land and ocean), ocean color, global vegetation, cloud characteristics, temperature and moisture profiles, and snow cover. MODIS will view the entire surface (land, oceans, clouds, aerosols, etc.) of the Earth every 1-2 days at a "moderate resolution" of one-quarter to one kilometer.

The Measurements Of Pollution In The Troposphere (MOPITT) instrument, provided by the Canadian Space Agency and built by COM DEV International of Cambridge, Ontario, will map carbon monoxide and methane concentrations at altitudes between 10 miles and the ground. MOPITT is an infrared gas correlation radiometer and will produce maps over the entire globe every 4-16 days. From these measurements the sources, motions and sinks of these gases can be determined.

The ASTER instrument, provided by Japan's Ministry of International Trade and Industry and built by NEC, Mitsubishi Electronics Company and Fujitsu, Ltd., will measure cloud properties, vegetation index, surface mineralogy, soil properties, surface temperature, and surface topography for selected regions of the Earth.

Hundreds of scientists from the U.S. and abroad are prepared to take full advantage of Terra observations to address key scientific issues and their environmental policy impacts.

Every 1 to 2 days Terra instruments will collect data over the entire Earth's surface, making measurements across a wide spectrum ranging from visible to infrared light. This research ideally will help scientists develop computer models of atmospheric, oceanic, and terrestrial dynamics and subsequently gain a better understanding of these complex systems and how they interact. With this information, scientists will improve their ability to predict significant changes in Earth's environment before they occur.

Terra will collect and archive an unprecedented quantity of high-quality multi-spectral data each day. The data will, for the first time, provide a high-resolution multi-faceted view of both seasonal and interannual changes in the terrestrial environment.

The Terra Project Office, located at Goddard, manages Terra development for NASA's Office of Earth Science in Washington, D.C. Goddard is responsible for the development of the satellite and the development and operation of the ground operations system. Spacecraft operations will be performed at a Mission Operations Center at Goddard.

Terra is part of a global research program known as NASA's Earth Science Enterprise, a long-term program that is studying changes in Earth's global environment.

NASA recognizes that the knowledge and data derived from Terra have significant practical value to society, and plans to foster increased access to, and use of, the information to make better, more informed decisions related to National needs which affect every American -- health and safety, economic wellbeing, and qualify of life in our communities.

A goal of the Earth Science Enterprise is to expand knowledge of the Earth System, from the unique vantage point of space. Earth Science Enterprise data, which will be distributed to researchers worldwide at the cost of reproduction, is essential to people making informed decisions about their environment.

Lockheed Martin Missiles & Space

Lockheed Martin delivers Terra Earth Observing System spacecraft to NASA customer for July launch

Terra is the flagship of the Earth Observing System (EOS); a series of spacecraft that represent the next landmark steps in NASA's leadership role to observe the Earth from the unique vantage point of space. Focused on key measurements identified by a consensus of U.S. and international scientists, Terra will enable new research into the ways that Earth's lands, oceans, air, ice, and life function as a total environmental system.

"It is very satisfying to have completed work on the Terra spacecraft and moved it to Vandenberg in preparation for launch," said Mike Kavka, Terra program manager at Lockheed Martin Missiles & Space in Valley Forge. "Our workforce here at the Delaware Valley facilities of Missiles & Space have been the premier builders of Earth-remote sensing spacecraft since the very beginning of the Space Age. So it is with particular pride that we deliver Terra, the final remote sensing satellite built here, to our NASA customer for this most important mission. As we consolidate our satellite operations in Sunnyvale, we will not forget the significant role our Delaware Valley employees played in monitoring and mapping our planet."

The launch of Terra will mark the beginning of a comprehensive monitoring of solar radiation, the atmosphere, the oceans, and the Earth's continents from a single space-based platform. The powerful imagery produced by Terra will show how pollution, drought and other environmental conditions affect Earth, providing scientists important new insights into this planet as a dynamic system.

The spacecraft will carry five high-resolution instruments comprising eight separate sensors that will gather data on clouds, aerosols, and the Earth's radiative balance, and measure surface properties and their interaction with the atmosphere:

• ASTER, the Advanced Spacebourne Thermal Emission and Reflection Radiometer, will provide high-resolution images of the land surface, water, ice, and clouds using three separate sensor subsystems covering 14 multi-spectral bands from visible to thermal infrared.

• CERES, the Clouds and Earth's Radiant Energy System, will measure Earth's radiation budget and atmospheric radiation from the top of the atmosphere using a broadband scanning radiometer with bolometers detectors.

• MISR, the Multi-angle Imaging Spectro Radiometer, will measures top-of-atmosphere, cloud and surface angular reflectance functions, and measure surface BRDF, aerosol, and vegetation properties using four spectral bands in each of nine imaging cameras oriented at different angles.

• MODIS, the Moderate Resolution Imaging Spectro-Radiometer, will measure biological and physical processes on land and the ocean using a cross-track scanning multi-spectral radiometer with 36 spectral bands from visible to thermal infrared.

• MOPITT, the Measurements of Pollution in the Troposphere, will measure carbon monoxide and methane in the troposphere using correlation spectroscopy with pressure modulated and length modulated gas cells.

Terra and subsequent EOS missions form the core of NASA's Earth Science Enterprise. The goal of the enterprise is to turn NASA's space-based observing technology and scientific expertise to the study of the planet Earth as an integrated system of land, ocean, atmosphere, ice, and biological processes. From the vantage point of space, we are beginning to understand how they work and how they interact. The questions posed and answers found in this grand scientific inquiry not only satisfy our curiosity, but yield knowledge of substantial practical value to society in weather and climate forecasting, in agriculture, in natural resource management, in urban and regional planning, and elsewhere.

Lockheed Martin Missiles & Space, based in Sunnyvale, Calif., is a leading supplier of satellites and space systems to military, civil government and commercial communications organizations around the world. These spacecraft and systems have enhanced military and commercial communications; provided new and timely remote-sensing information; and furnished new data for thousands of scientists studying our planet and the universe.

High and low resolution images of the Terra spacecraft are available for downloading.

Photo Credit: Russ Underwood, Lockheed Martin Missiles & Space

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