NP-119 Science in Orbit: The Shuttle & Spacelab Experience, 1981-1986

 

Chapter 7

Surveying Our Planet: Earth Observations

 


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view of Earth from the space shuttle

 

[81] Blue and green, variable swatches of brown peeking through white clouds, continent after continent - the whole world streams by in a 90-minute Shuttle orbit. From space, our planet looks beautiful but fragile.

Besides aesthetic enjoyment of the view, there are many practical reasons to observe Earth from space. From orbit, it is possible to see both natural and manmade features that are not easily discernible from the ground.

This unique perspective is advantageous for mapping, resource monitoring, geology, archaeology, and oceanography.

Maps are basic prerequisites for planning and development, yet despite centuries of exploration about 60 percent of the world has never been mapped in high fidelity, and many existing maps are outdated. Ground-based mapping is tedious and mistakes are easily made; thousands of workyears and millions of dollars would be required to update maps with aerial photography. Satellites such as NASA's Landsat have provided valuable electronic images, but detailed resolution suffers because the satellites are in high orbits and cover large areas. Imaging from the Shuttle, however, may prove to be an effective and economical way to map large areas. The Shuttle's position in low-Earth orbit gives cameras a global view but also allows them to be focused in sharp detail on smaller regions.

At the same time, other hidden treasures may be uncovered. The same techniques used for mapping may reveal locations of minerals or water, artifacts covered from view by sand or vegetation, geological formations, patterns in ocean waves, and glacier movements. Hidden in the jungles, sand dunes, and other undeveloped regions lie untapped resources and historical artifacts. Images from space are being used to uncover some of Earth's secrets.

With a global view from the Shuttle and Spacelab, scientists can focus on geographic details and also see large-scale features that hint of Earth's physical history. The terrestrial land and water masses are part of an interactive, evolving system. Some of the changes are natural processes that have been under way for billions of years; others are the effects of mankind, for we are not mere spectators of nature but active contributors to changes in the environment. Most geological processes occur over grand timescales and are not readily apparent at ground level. From space, however, scientists can see evidence of continental drift, land masses that may once have been connected, and sites that are the birthplaces of volcanos or the burial grounds of ancient rivers. By piecing images together to form a mosaic, they can develop models and perhaps predict future changes, both natural and in response to human activity.

[82] The planetary perspective from space reveals modern changes: depleted mineral and energy resources, cut forests, spills of oil and chemicals into the oceans, networks of roads and canals, and sprawling cities. There is clear evidence that we can alter our habitat significantly within a few human generations.

Aboard the Shuttle, various remote sensing techniques have been used for mapping and other purposes such as the identification of minerals, vegetation studies, acid rain monitoring, geological surveys, and oceanographic investigations. These techniques include photography, radar, and spectroscopy. Often, data obtained by different techniques and instruments are complementary, leading to a better understanding of the feature being observed.

However, it is not enough simply to observe; the information must be used by the international scientific community. Photographs and data from space are returned to Earth, processed, and quickly distributed to investigators around the world. Data from several recent Shuttle missions are already being shared by investigators from every continent. This spirit of cooperation and purpose is essential for understanding and protecting our common homeland, the planet Earth.

 


One world can be mapped more quickly and accurately from orbit. A camera carried in the Shuttle payload bay made this photograph which covered 63,366 square kilometers (25,346 square miles) of the eastern Australian coast and the Great Barrier Reef and was used to update maps of the region.

One world can be mapped more quickly and accurately from orbit. A camera carried in the Shuttle payload bay made this photograph which covered 63,366 square kilometers (25,346 square miles) of the eastern Australian coast and the Great Barrier Reef and was used to update maps of the region.


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Radar is another remote sensing technique for surveying our planet. This view of Mount Shasta, California, was generated using two Shuttle Imaging Radar-B (SIR-B) images acquired at different angles.

Radar is another remote sensing technique for surveying our planet. This view of Mount Shasta, California, was generated using two Shuttle Imaging Radar-B (SIR-B) images acquired at different angles. Similar contour modeling experiments were carried out for Africa and South America. Using these images, geologists are identifying features such as faults, folds, fractures, dunes, and rock layers.


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In this Metric Camera image of the White and Blue niles in Sudan, Africa, photographic details as small as 10 meters (33 feet) can be resolved.

In this Metric Camera image of the White and Blue niles in Sudan, Africa, photographic details as small as 10 meters (33 feet) can be resolved. It is possible to identify irrigation and cultivation structures. Developing countries are using these images to make some of their first resource planning maps.

 

High-Resolution Photograph: Two Shuttle instruments, the Metric Camera and the Large Format Camera, combined techniques and equipment for aerial photography with the global view from space to acquire high-resolution images suitable for mapping. Experts say it would take 10 years to make aerial photographs of the regions surveyed by the Metric Camera during 3 days of the 1 O-day Spacelab 1 mission. After crewmembers saved the experiment by fixing a film jam, 11 million square kilometers (4.2 million square miles) were photographed during the mission. Each 23-centimeter square (9-inch square) film frame covered an area 190 by 190 kilometers (118 by 118 miles), and resolution was 20 meters (66 feet). Roads with widths of 10 meters or more can be recognized. The images are being used to [85] produce maps at a scale of 1:100,000.

The Metric Camera, a modified aerial survey mapping camera (the Zeiss RMK-A 30-23), was mounted on the optical quality window in the ceiling of the Spacelab module. Three types of film were used: black and white negative, color transparency, and false-color infrared. The infrared film makes it easier to identify details not readily apparent in regular color. Photos were taken with an overlap of 60 to 80 percent so that stereoscopic evaluations of overlapping pairs are possible. This helps investigators determine the correct height and shape of certain features.

Details of agricultural patterns, land use, rivers and waterways, geological formations, historical sites, major highways, and buildings are visible in the images. European countries sponsoring the camera's flight are using the images to update maps, some of which have not been revised since the nineteenth century. For example, mountain heights in the Alps have been measured with greater accuracy using the new images.

The International science community submitted 100 proposals for use of the photographs. With these images, developing countries in Africa, Asia, and Latin America are making some of their first resource planning maps. The camera took unprecedented photographs of one of the most isolated regions of China, the Qinghai Plateau, causing a major revision in knowledge of the area.

These images from space reveal imprints left by past and present cultures. Photographs taken over Mexico are being used for archeological research. Traces of the Great Wall have been identified in images of western China.

Other images record features of geological and agricultural importance. Sand dunes hundreds of kilometers long and 70 meters (230 feet) high....

 


Cartographers were able to see major streets and buildings by enlarging this Metric Camera photograph of Munich, Germany.

Cartographers were able to see major streets and buildings by enlarging this Metric Camera photograph of Munich, Germany.


The Strait of Hormuz (Iran) shows recent geological developments in the form of salt dunes, coastal terraces, and uplifted reefs.

The Strait of Hormuz (Iran) shows recent geological developments in the form of salt dunes, coastal terraces, and uplifted reefs.


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The Metric Camera can photograph sparsely populated, isolated regions, such as the Horn of Africa.

The Metric Camera can photograph sparsely populated, isolated regions, such as the Horn of Africa.

 

....were photographed in one of the least known regions of the Sahara Desert. Photographs of the Strait of Gibraltar show the geological and morphological evidence of a former land connection between Africa and Europe. Irrigation and cultivation structures on farms in the Nile River Valley can be identified clearly.

The Large Format Camera flown on the OSTA-3 mission operated similarly to the Metric Camera but was four times bigger and was mounted outside on a Spacelab pallet. The camera produced photographs that were 22.9 by 45.7 centimeters (9 by 18 inches), covering an area of approximately 180 by 362 kilometers (112 by 225 miles). This camera also took one photo after another with 20 to 80 percent overlap so that the images could be compared.

The average spatial resolution of the photographs was 10 to 15 meters (32 to 50 feet), good enough to produce [87] maps at scales of 1:50,000. The resolution is slightly better than the Metric Camera's because a state-of-the-art lens, higher resolution film, and a motion compensation system were used and because the camera was exposed directly to space instead of taking photographs through a window. The resolution was good enough to detect buildings, houses, and streets but not automobiles. In one image, contrails left by planes traveling between New York and Europe can be seen.

Some 2,300 exposures were made during 73 Earth viewing passes. As with the Metric Camera, black-and-white negatives, color transparencies, and color infrared film were used. Some new high-resolution films were tested and proved to be very effective.

The mission was supported by 245 investigators who analyzed data for use in various fields; most of them were from agencies other than NASA....

 


Roads and major buildings are readily evident in this enlarged Large Format Camera image of Mobile, Alabama.

Roads and major buildings are readily evident in this enlarged Large Format Camera image of Mobile, Alabama.


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Fossil fuel deposits have been located in the Middle East using Large Format Camera images.

Fossil fuel deposits have been located in the Middle East using Large Format Camera images. This image covers 153,030 square kilometers (59,865 square miles) in Turkey, Lebanon, Israel, Syria, Jordan, Saudi Arabia, and Iraq.

 

....including the National Oceanic and Atmospheric Administration, the Departments of Energy and Defense, the Corps of Engineers, and the U.S. Geological Survey. Teams worked at 500 field sites during the mission, collecting on-site data to confirm or complement photographic information.

High-resolution photographs were taken in the United States, and buildings, streets, and land use patterns were clearly visible. Land types around the world were photographed, including the highest point Mount Everest in the Himalayas (29,000 feet above sea level) - and one of the lowest - the Dead Sea area in the Holy Land (1,300 feet below sea level). The structure of the Great Barrier Reef could be discerned from photographs of the East Coast of Australia; these and other images are being used to update Australian maps.

The Large Format Camera images are being used for a variety of other projects. Updated topography maps are being made of a national forest in Maine, and land surveys are being made of Wyoming and South Dakota. Fossil fuel deposits have been located in the Middle East, and possible water sources have been identified in Southern Egypt and Ethiopia. By enlarging the images, scientists also may have found some previously undetected impact craters. The images revealed the first proof that blocks of land in China are being forced into the Pacific Ocean along the Kunlan fault; geologists have sent two expeditions to China to investigate the evidence in the images.

 


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Left [above]: The continuing collision between the Indian subcontinent and Asia has resulted in the formation of the Tibetan plateau, the Himalayas, and major faults.

Left [above]: The continuing collision between the Indian subcontinent and Asia has resulted in the formation of the Tibetan plateau, the Himalayas, and major faults. Until high-resolution Large Format Camera images were obtained, there was no direct geological evidence for movement of the faults. This image, with a resolution better than 10 meters (32.8 feet), reveals a 15-kilometer (9.3-mile) segment of the Kunlan fault north of the Ho Sai Hu Basin; the fault stretches from the left of the image to the upper right corner.

Below: Streams flowing southward from the fault scarp have been offset by 1 kilometer (0.62 miles) where they cross the fault trace. Overall, the fault zone is about 1 to 2 kilometers wide; the scarp formed by the most recent movements is about 100 meters (330 feet) high.

Below: Streams flowing southward from the fault scarp have been offset by 1 kilometer (0.62 miles) where they cross the fault trace. Overall, the fault zone is about 1 to 2 kilometers wide; the scarp formed by the most recent movements is about 100 meters (330 feet) high.



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The Shuttle Imaging Radar (SIR) was carried on a pallet (left foreground) in the payload bay.

The Shuttle Imaging Radar (SIR) was carried on a pallet (left foreground) in the payload bay.

 

Imaging Through the Clouds, Vegetation, and Surface: Radar is another useful technique for high resolution mapping. Unlike photography, radar beams can pierce cloud cover and penetrate dense vegetation covering inaccessible tropical regions. Some interesting discoveries have been made using the Shuttle Imaging Radar (SIR) flown aboard the OSTA-1 and OSTA 3 missions.

As the radar is carried along the flight path of the Shuttle, it functions as a greatly elongated antenna. The antenna radiates pulses of microwave energy which are reflected by target areas. The characteristics of the reflected pulses vary according to the surface texture (morphology) and type. For example, sand will alter the radar signal differently than rock or vegetation. The responses are digitized, recorded, and resumed to Earth where they are processed to produce images.

SIR-A, the first flight of the Shuttle Imaging Radar, was very successful, acquiring radar images of approximately 26 million square kilometers (10 million square miles), with a resolution of 40 meters (131 feet). The long microwaves were able to penetrate dry sand dunes in the Sahara Desert and image a vanished river system and valleys buried under the sand. Since the Shuttle radar uncovered the remnants of the river, sites of oases have been discovered, and Stone Age artifacts associated with river deposits suggest that these valleys may have been sites of early human occupation. The dry river beds have been used as indicators of water flow in the area; wells have been drilled and several are producing water.

[91] The success of the first flight confirmed that radar could be used from the Shuttle. After its return, the instrument was refurbished, updated to improve its resolution and capabilities, and reflown on a second mission (SIR-B) at a relatively low cost. The resolution of the new radar was 25 meters (82 feet), and the antenna was modified to tilt at angles varying between 15 and 57 degrees. This allowed scientists to gather extra information by "looking" at a target from different angles. This capability permitted viewing a larger area of Earth, since the radar was no longer restricted to the ground directly beneath the Shuttle's orbit. It also allowed large areas to be mapped by varying the look angles so that a mosaic could be made of adjacent areas imaged over several days.

Even though there were some telemetry problems during the OSTA-3 mission, approximately 6 million square miles of Earth were imaged. The drainage channels associated with the vanished river again were revealed. The first sighting also inspired another experiment to see how far the radar could penetrate below the surface of the Earth.

A series of receivers were buried at different depths in a dry lake at Walker Lake, Nevada. During a pass over the site, the deepest receiver, at a depth of 1 meter (3 feet), picked up the radar signals. Soil moisture content also was measured; this type of data could be used for locating water sources and for agricultural monitoring and crop forecasting.

 


Left: In the Landsat image of a remote part of the desert in Egypt, only surface features of dunes are visible.

Right: SIR-A was able to penetrate beneath the sand to reveal the site of an ancient river bed.

Left: In the Landsat image of a remote part of the desert in Egypt, only surface features of dunes are visible.

Right: SIR-A was able to penetrate beneath the sand to reveal the site of an ancient river bed.

 

[92] Investigators also wanted to see how well the radar would penetrate dense areas of vegetation and reveal hidden features, such as breeding grounds for malaria-carrying mosquitos. To do this, they tried to see through the tropical canopies in swamp areas of Bangladesh. The radar images did show areas of still water typical of mosquito habitats.

The multi-incidence-angle viewing was used to distinguish surface materials on the basis of their roughness characteristics when imaged at different angles. This enabled investigators to make a three-dimensional model that showed subtle geological details of Mount Shasta, California. Similar contour modeling experiments were carried out in East and South Africa and South America. Structural and geological features such as faults, folds, fractures, dunes, and rock layers are clearly visible.

The multiangle viewing was used to classify different types of trees and vegetation by their reflectance properties. (This was possible because different plants reflect radar at amplitudes that vary in pattern as the angle of the radar antenna is changed.) Plant types were successfully identified in Florida and South America.

Other images revealed data about the oceans, natural resources, and geology. Ocean waves of 20 meters (65 feet) or more were measured; polar ice floes were imaged from space; and evidence of oil spills was detected in oceans. The effects of clear-cutting were seen in Germany; tree populations may be monitored from space so that excessive cutting can be avoided. Geological surface boundaries, which may reveal clues to rock types, lava....

 


(A) The Ganges River Delta region of Bangladesh. (B) Artificial colors were used to enhance differences in surface characteristics in this SIR-B image of Hawaii. (C) This image of northeastern Florida is being used to assess coniferous timber stands and management practices.

(A) The Ganges River Delta region of Bangladesh was the site of an experiment to test radar imaging through tropical vegetation. This image was one in a series that proved that soil surfaces and flooded areas under a mangrove canopy can be mapped. Artificial colors in the computer-processed image enhance differences in vegetation and terrain. Pink and yellow represent forested areas, seen most vividly in the coastal forest preserve of Sundurban on the Indian Ocean. The textured green and pink (center) are cultivated fields connected by extensive irrigation and drainage channels. The more uniform rose-hued area (top) is part of the Ganges flood plain subject to flooding during monsoon season.

(B) Artificial colors were used to enhance differences in surface characteristics in this SIR-B image of Hawaii. South Point is the bright red surface (bottom), Kilauea Crater is the circular feature (center), and the two black lines (upper right) are air strips at Hilo Airport. red areas represent smooth pahoehoe lava, and light blue is vegetation cover.

[93] (C) This image of northeastern Florida is being used to assess coniferous timber stands and management practices. The artificial colors in this computer-processed image enhance differences in vegetation and terrain. Yellowish green areas are generally stands of cypress drenched in early morning dew. Dark green and purple areas are agricultural fields, and bright orange regions denote drainage channels. The Gulf of Mexico is at the bottom.



(D) The Rhine River, the Black Forest, and West Germany appear in this SIR-B investigation of the utility of radar imagery for classifying crops and monitoring the health of timber stands.

(D) The Rhine River, the Black Forest, and West Germany appear in this SIR-B investigation of the utility of radar imagery for classifying crops and monitoring the health of timber stands. The bright spots in the images are urban areas where buildings strongly reflect the radar signal. Freiberg is the largest bright spot in the image. The Black Forest is just above Freiberg. Mottled dark spots represent clear-cut areas in the forest, which appears as a uniform gray (left). The small bright circle (lower right) is the octogonal walled city of Neuf Brisach in France.


 

...flows inside volcanos, and previously undetected impact craters were imaged.

SIR-B took advantage of an unexpected opportunity to monitor Hurricane Josephine. The instrument detected wave patterns associated with the storm's movement and speed. This type of information would be useful in determining when and how a storm might strike a coast.

During the SIR-B mission, more than 40 co-investigators were dispatched at various field sites around the world. Their observations at places being studied from space helped to confirm that the data obtained are accurate.

[94] Locating Minerals and Studying the Oceans: Although photography and radar are able to reveal surface geological features, they are not useful for identifying specific minerals. The Shuttle Multispectral Infrared Radiometer demonstrated that this can be done by another technique - spectroscopy. Minerals on Earth reflect light at specific wavelengths or spectral lines that can be identified with a spectrometer.

This experiment was inspired by the use of Landsat data to identify limonite, a major iron ore. The Landsat satellite has four broad spectral channels at short wavelengths, but because many minerals reflect at longer wavelengths, they might be seen by a differently tuned instrument. The Shuttle Multispectral Infrared Radiometer records spectra in 10 channels between 0.5 and 2.4 microns at a spatial resolution of 100 meters (328 feet). In particular, investigators are interested in identifying carbonate and hydroxl-bearing minerals, such as clays, which radiate brightly in the 2.0 to 2.4 micron spectral range.

As the instrument makes measurements, the ground track is photo graphed by a 16-mm camera so that mineral spectra can be matched with locations. During the second Shuttle flight, 400,000 spectra were obtained over the eastern United States, Mexico, southern Europe, North Africa, the Middle East, and China.

 


This false-color image of the Yellow Sea made for the Ocean Color Experiment shows chlorophyll pigments (green and yellow) indicating the presence of phytoplankton.

This false-color image of the Yellow Sea made for the Ocean Color Experiment shows chlorophyll pigments (green and yellow) indicating the presence of phytoplankton.

 

In the laboratory before the flight, the instrument was calibrated by obtaining spectra of pure minerals. For verification, the spectral data taken in orbit were compared with laboratory spectra and with the spectra of minerals collected at the observation sites. The next steps in the evolution of this instrument are to increase spectral resolution for enhanced ability to identify specific minerals and to eliminate spectral absorption by vegetation which confounds the mineral spectra.

Interesting mineral signatures were identified in the Baja region of Mexico. A large hydrothermally altered area was identified in Mexico for the first time; the rock in this area is associated with many types of ore deposits and contains minerals having intense, distinctive spectral signatures. The minerals identified were clays (pryophyllite, dickite, diaspore, kaolinine, and K-mica) along with molybdenum, boron, tin, zirconium, and silver. Field trips to the area after the mission confirmed that this was a thermally altered terrain containing many of the minerals identified by space spectroscopy.

The ocean also reveals its biological contents and circulation patterns by the reflectance properties of its various components. The OSTA-1 Ocean Color Experiment employed an eight-channel multispectral imaging sensor to measure solar radiation reflected from ocean surfaces at wavelengths of 0.4 to 0.S microns. The instrument was designed to detect variations in the pigmentation of ocean surface waters. The color varies in relationship to the presence of chlorophyll in phytoplankton algae.

[95] The ocean images were digitized and enhanced by computer to emphasize patterns of chlorophyll distribution and, in one case, to show bottom topography. The chlorophyll pattern in the Yellow Sea between China and Korea was evident in one scene, and the effects of the discharge of rivers into the sea were observed.

As patches of plankton were carried in the ocean currents, reflectivity changes were observed over the Strait of Gibraltar during successive Shuttle passes. These were used to estimate the direction and velocity of surface currents near the entrance to the Mediterranean.

The variability in water depth over the Grand Bahama Bank was estimated using the blue-green channel of the instrument. The area is characterized by its scarcity of planktonic marine life, and the blue-green components of visible light that are usually absorbed by chlorophyll penetrated the water and were reflected from the bottom. Using the return signal, investigators estimated water depths ranging from a few meters to tens of meters.

The Ocean Color Experiment demonstrated the feasibility of mapping chlorophyll concentration in the open ocean. This capability could be used to monitor global changes in phytoplankton abundances from space. Phytoplankton are a key building block at the base of Earth's food chain, and information on their distribution and total abundance could be important to long-term studies of global ecology.

 

Refining Observation Techniques:

The Shuttle missions also have given scientists an opportunity to refine Earth observation techniques. For example, stereoscopic viewing has been accomplished using both photography and radar images. This results in greater accuracies when measuring heights and distances.

 


The digitized image (bottom [right]) was made for the Feature Identification and Location Experiment (FILE) and compared to the ground truth image (top [left])

The digitized image (bottom [right]) was made for the Feature Identification and Location Experiment (FILE)

The digitized image (bottom [right]) was made for the Feature Identification and Location Experiment (FILE) and compared to the ground truth image (top [left]). The FILE system denotes clouds as white, ocean as blue, and land as green. Similar systems may be placed on satellites so that valuable viewing time is not wasted on cloudy areas.


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As part of NASA's Earth Observation System (EOS) program, a polar orbiting platform will allow instruments to view the entire Earth 15 times a day.

As part of NASA's Earth Observation System (EOS) program, a polar orbiting platform will allow instruments to view the entire Earth 15 times a day.

 

The Feature Identification and Location Experiment (FILE, OSTA-1 and OSTA-3) tested a system that will help satellites identify good viewing conditions. The idea is to save precious viewing time by preventing remote sensing satellites from gathering unusable data during cloud cover. The instrument uses wavelengths to classify surface features into four categories: (1) vegetation, (2) bare ground, (3) water, and (4) clouds, snow, and ice.

Essential parts of the instrument are two television cameras, each consisting of an array of charge-coupled detectors. One camera senses reflected radiation at the 0.65-micron wavelength (visible red), and the other senses radiation at 0.85 microns (near infrared). The ratio of the two signals can be used to categorize the scene as either mostly clouds or mostly another feature. Images from the two cameras are digitized and color-coded according to category. OSTA images show that the ratio correctly identified the various features.

 

Continuous Global Observations:

As we study Earth from space, national boundaries become less distinct. With the Shuttle, scientists around the world have taken the first step to study Earth as an integrated system. It is only through continued international cooperation in planning and carrying out investigations that our planet can be studied on a global scale. This effort requires a coordinated program of long-term, systematic observations. The new technology tested aboard the Space Shuttle can be attached to platforms and the Space Station for continuous viewing and longer stays in space. To understand and verify these observations, worldwide ground and airborne observations will continue to be critical.

In the Space Station era, Earth observations will meet the needs of a broad and diverse community of scientists. [97] Some scientists need close-up views of local areas, others need a view of the Earth's entire surface, and still others need to view the atmosphere. To meet these requirements, an Earth Observation System (EOS) is being developed.

Instruments will be placed on platforms that orbit Earth's poles at inclinations higher than the Space Station where they have a more global view of our planet. Sophisticated instruments on polar platforms will increase the types of observations possible; scientists will be able to focus instruments on almost any point on the Earth instantaneously, view with less cloud interference, select observing times, survey small scale, rapidly changing events, and monitor events under various cyclic conditions.

Other instruments may be attached to the Space Station, which is at a lower altitude and inclination and offers better close-up views of tropical forests and other areas. The Space Station also will be essential for assembling, testing, and deploying instruments to higher orbits as well as for servicing, repairing, and upgrading instruments.

The EOS will be coupled to advanced information systems to ensure that data are collected, distributed, analyzed, and archived for use by the science community. In the meantime, the Shuttle/Spacelab must still be used to develop the instruments and test the technologies for Earth observations. The Shuttle also is valuable as a testbed for information systems and for developing procedures for remotely operated instruments.

The Shuttle will remain in service as a platform for Earth observations. Evolving from the Shuttle Imaging Radar on OSTA-1 and OSTA-3, the Shuttle Imaging Radar-C will gather even more information by using several frequencies and polarizations to map the entire globe. The Large Format Camera may be carried as a complement to provide visible light imagery of the world and to improve global cartography. The ability of the Shuttle Imaging Spectrometer Experiment (SISEX) to provide images of the Earth in 128 spectral bands at once will be tested on the Shuttle before it becomes a part of the next generation of Earth-monitoring satellites.

To solve some of the problems in a modern, rapidly changing world, Earth must be studied as an integrated system. This requires an interdisciplinary approach, with life scientists, atmospheric scientists, geologists, and investigators from many other fields working together. This united effort can only be accomplished in space where we see the Earth as a whole.

 

Earth Observation Investigations

OSTA-1/STS-2

Feature Identification and Location Experiment (FILE)

R.T. Schappell, Martin-Marietta, Denver, Colorado

.

Ocean Color Experiment

H.H. Kim, NASA Goddard Space Flight Center, Greenbelt, Maryland

.

Shuttle Imaging Radar (SIR-A)

C. Elachi, NASA Jet Propulsion Laboratory, Pasadena, California

.

Shuttle Multispectral Infrared Radiometer

A. Goetz, University of Colorado, Boulder, Colorado

.

Spacelab 1/STS-9

Metric Camera

M. Reynolds, European Space Agency, Noordwijk

G. Konecny, University of Hannover, Germany

.

Microwave Remote Sensing Experiment

G. Dieterle, European Space Agency, Paris, France

.

OSTA-3/41-G

Feature Identification and Location Experiment (FILE)*

W.E. Sivertson, NASA Langley Research Center, Hampton, Virgina

.

Large Format Camera

B.H. Mollberg, NASA Johnson Space Center, Houston, Texas

.

Shuttle Imaging Radar (SIR-B)

C. Elachi, NASA Jet Propulsion Laboratory, Pasadena, California

.

* Reflight

 
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