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L-Band Radar and Space Shuttle Endeavour and Earth
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Safsaf Oasis, Egypt SIR-C/X-
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These images show two views
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3/26/98
| Date |
3/26/98 |
| Description |
These images show two views of a region of south-central Egypt, each taken by a different type of spaceborne sensor. On the left is an optical image from the Landsat Thematic Mapper , and on the right is a radar image from the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). This comparison shows that the visible and infrared wavelengths of Landsat are only sensitive to the materials on the surface, while the radar wavelengths of SIR-C/X-SAR can penetrate the thin sand cover in this arid region to reveal details hidden below the surface. Field studies in this area indicate that the L-band radar can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels, shown at the bottom of this image, are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. Only the most recently active channels are visible in the Landsat scene. Some geologic structures at the surface are visible in both images. However, many buried features, such as rock fractures and the blue circular granite bodies in the upper center of the image on the right, are visible only to the radar. The Safsaf Oasis is located near the bright yellow feature in the lower left center of the Landsat image. Scientists are using the penetrating capabilities of radar imaging in desert areas to study structural geology, mineral exploration, ancient climates, water resources and archaeology. Each image is 30.8 kilometers by 25.6 kilometers (19.1 miles by 15.9 miles) and is centered at 22.7 degrees north latitude, 29.3 degrees east longitude. North is toward the upper right. In the Landsat image, the colors are assigned as follows: red is Band 7 (mid-infrared), green is Band 4 (near infrared), and blue is Band 1 (visible blue light). The colors assigned to the radar frequencies and polarizations are as follows: red is L- band, horizontally transmitted and received, green is C-band, horizontally transmitted and received, and blue is X-band, vertically transmitted and received. The radar image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 16, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Earth Science Enterprise. The Landsat Program is managed jointly by NASA, the National Oceanic and Atmospheric Administration and the United States Geological Survey. |
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Galapagos L-band, HH
This is an image showing par
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4/15/94
| Date |
4/15/94 |
| Description |
This is an image showing part of Isla Isabella in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar on the 40th orbit of the space shuttle Endeavour. The image is centered at about 0.5 degree south latitude and 91 degrees west longitude and covers an area of 75 by 60 kilometers (47 by 37 miles). The radar incidence angle at the center of the image is about 20 degrees. The western Galapagos Islands, which lie about 1,200 kilometers (750 miles) west of Ecuador in the eastern Pacific, have six active volcanoes similar to the volcanoes found in Hawaii. Since the time of Charles Darwin's visit to the area in 1835, there have been over 60 recorded eruptions on these volcanoes. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image. The Galapagos Islands are one of the SIR-C/X-SAR supersites and data of this area will be taken several times during the flight to allow scientists to conduct topographic change studies and to search for different lava flow types, ash deposits and fault lines. ----- Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI). ##### |
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Flevoland X, C & L band
This is a three-frequency fa
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4/18/94
| Date |
4/18/94 |
| Description |
This is a three-frequency false color image of Flevoland, The Netherlands, centered at 52.4 degrees north latitude, 5.4 degrees east longitude. This image was acquired by the Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard space shuttle Endeavour on April 14, 1994. It was produced by combining data from the X-band, C-band and L-band radars. The area shown is approximately 25 kilometers by 28 kilometers (15-1/2 by 17-1/2 miles). Flevoland, which fills the lower two-thirds of the image, is a very flat area that is made up of reclaimed land that is used for agriculture and forestry. At the top of the image, across the canal from Flevoland, is an older forest shown in red, the city of Harderwijk is shown in white on the shore of the canal. At this time of the year, the agricultural fields are bare soil, and they show up in this image in blue. The changes in the brightness of the blue areas are equal to the changes in roughness. The dark blue areas are water and the small dots in the canal are boats. This SIR-C/X-SAR supersite is being used for both calibration and agricultural studies. Several soil and crop ground-truth studies will be conducted during the shuttle flight. In addition, about 10 calibration devices and 10 corner reflectors have been deployed to calibrate and monitor the radar signal. One of these transponders can be seen as a bright star in the lower right quadrant of the image. This false-color image was made using L- band total power in the red channel, C-band total power in the green channel, and X-band VV polarization in the blue channel. ----- Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v. (DLR), the major partner in science, operations and data processing of X-SAR. ##### |
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Yellowstone Park, Wyoming L
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These two radar images show
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10/5/94
| Date |
10/5/94 |
| Description |
These two radar images show the majestic Yellowstone National Park, Wyoming, the oldest national park in the United States and home to the world's most spectacular geysers and hot springs. The region supports large populations of grizzly bears, elk and bison. In 1988, the park was burned by one of the most widespread fires to occur in the northern Rocky Mountains in the last 50 years. Surveys indicated that 793,880 acres of land burned. Of that, 41 percent was burned forest, with tree canopies totally consumed by the fire, 35 percent was a combination of unburned, scorched and blackened trees, 13 percent was surface burn under an unburned canopy, 6 percent was non-forest burn, and 5 percent was undifferentiated burn. Six years later, the burned areas are still clearly visible in these false-color radar images obtained by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. The image at the left was obtained using the L-band radar channel, horizontally received and vertically transmitted, on the shuttle's 39th orbit on October 2, 1994. The area shown is 45 kilometers by 71 kilometers (28 miles by 44 miles) in size and centered at 44.6 degrees north latitude, 110.7 degrees west longitude. North is toward the top of the image (to the right). Most trees in this area are lodgepole pines at different stages of fire succession. Yellowstone Lake appears as a large dark feature at the bottom of the scene. At right is a map of the forest crown, showing its biomass, or amount of vegetation, which includes foliage and branches. The map was created by inverting SIR-C data and using in situ estimates of crown biomass gathered by the Yellowstone National Biological Survey. The map is displayed on a color scale from blue (rivers and lakes with no biomass) to brown (non-forest areas with crown biomass of less than 4 tons per hectare) to light brown (areas of canopy burn with biomass of between 4 and 12 tons per hectare). Yellow indicates areas of canopy burn and mixed burn with a biomass of between 12 to 20 tons per hectare, light green is mixed burn and non-burn forest with a biomass of 20 to 35 tons per hectare, and green is non-burned forest with a biomass of greater than 35 tons per hectare. Forest recovery from the fire seems to depend on fire intensity and soil conditions. In areas of severe canopy burn and poor soil conditions, crown biomass was still low in 1994 (indicated by the brown areas at the center left), whereas in areas of mixed burn with nutrient-rich soils, seen west of Yellowstone Lake, crown biomass has increased significantly in six years (indicated by the yellow and light green areas). Imaging fire- affected regions with spaceborne radar illustrates SIR-C/X-SAR's keen abilities to monitor regrowth after a fire. Knowing the amount of carbon accumulated in the atmosphere by regenerating forest in the 20 to 50 years following a fire disturbance is also a significant factor in understanding the global carbon cycle. Measuring crown biomass is necessary to evaluate the effects of past and future fires in specific regions. ----- Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR- C/X-SAR) are part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L- band (24 cm), C-band (6 cm), and X-band (3 cm). The multi- frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes that are caused by nature and those changes that are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. |
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Glasgow, Missouri L band, bl
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This is a false-color L-band
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10/7/94
| Date |
10/7/94 |
| Description |
This is a false-color L-band image of an area near Glasgow, Missouri, centered at about 39.2 degrees north latitude and 92.8 degrees west longitude. The image was acquired using the L-band radar channel (horizontally transmitted and received and horizontally transmitted/vertically received) polarizations combined. The data were acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on orbit 50 on October 3, 1994. The area shown is approximately 37 kilometers by 25 kilometers (23 miles by 16 miles). The radar data, coupled with pre-flood aerial photography and satellite data and post-flood topographic and field data, are being used to evaluate changes associated with levee breaks in landforms, where deposits formed during the widespread flooding in 1993 along the Missouri and Mississippi Rivers. The distinct radar scattering properties of farmland, sand fields and scoured areas will be used to inventory flood plains along the Missouri River and determine the processes by which these areas return to preflood conditions. The image shows one such levee break near Glasgow, Missouri. In the upper center of the radar image, below the bend of the river, is a region covered by several meters of sand, shown as dark regions. West (left) of the dark areas, a gap in the levee tree canopy shows the area where the levee failed. Radar data such as these can help scientists more accurately assess the potential for future flooding in this region and how that might impact surrounding communities. ----- Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR. ##### |
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Safsaf Oasis, Egypt
PIA00737
Sol (our sun)
L-Band Imaging Radar
| Title |
Safsaf Oasis, Egypt |
| Original Caption Released with Image |
These images show two views of a region of south-central Egypt, each taken by a different type of spaceborne sensor. On the left is an optical image from the Landsat Thematic Mapper, and on the right is a radar image from the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). This comparison shows that the visible and infrared wavelengths of Landsat are only sensitive to the materials on the surface, while the radar wavelengths of SIR-C/X-SAR can penetrate the thin sand cover in this arid region to reveal details hidden below the surface. Field studies in this area indicate that the L-band radar can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels, shown at the bottom of this image, are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. Only the most recently active channels are visible in the Landsat scene. Some geologic structures at the surface are visible in both images. However, many buried features, such as rock fractures and the blue circular granite bodies in the upper center of the image on the right, are visible only to the radar. The Safsaf Oasis is located near the bright yellow feature in the lower left center of the Landsat image. Scientists are using the penetrating capabilities of radar imaging in desert areas to study structural geology, mineral exploration, ancient climates, water resources and archaeology. Each image is 30.8 kilometers by 25.6 kilometers (19.1 miles by 15.9 miles) and is centered at 22.7 degrees north latitude, 29.3 degrees east longitude. North is toward the upper right. In the Landsat image, the colors are assigned as follows: red is Band 7 (mid-infrared), green is Band 4 (near infrared), and blue is Band 1 (visible blue light). The colors assigned to the radar frequencies and polarizations are as follows: red is L-band, horizontally transmitted and received, green is C-band, horizontally transmitted and received, and blue is X-band, vertically transmitted and received. The radar image was acquired by the Spaceborne Imaging Radar-C/ X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 16, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Earth Science Enterprise. The Landsat Program is managed jointly by NASA, the National Oceanic and Atmospheric Administration and the United States Geological Survey. Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the, global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations, and data processing of X-SAR. |
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Radar Image of Galapagos Isl
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PIA00499
Sol (our sun)
L-Band Imaging Radar
| Title |
Radar Image of Galapagos Island |
| Original Caption Released with Image |
This is an image showing part of Isla Isabella in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar on the 40th orbit of the space shuttle Endeavour. The image is centered at about 0.5 degree south latitude and 91 degrees west longitude and covers an area of 75 by 60 kilometers (47 by 37 miles). The radar incidence angle at the center of the image is about 20 degrees. The western Galapagos Islands, which lie about 1,200 kilometers (750 miles) west of Ecuador in the eastern Pacific, have six active volcanoes similar to the volcanoes found in Hawaii. Since the time of Charles Darwin's visit to the area in 1835, there have been over 60 recorded eruptions of these volcanoes. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image. The Galapagos Islands are one of the SIR-C/X-SAR supersites and data of this area will be taken several times during the flight to allow scientists to conduct topographic change studies and to search for different lava flow types, ash deposits and fault lines. Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI). |
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Bora Bora, Tahaa, and Raiate
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PIA06660
Sol (our sun)
C/X-Band Synthetic Aperture
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| Title |
Bora Bora, Tahaa, and Raiatea, French Polynesia, Landsat and SIR-C Images Compared to SRTM Shaded Relief and Colored Height |
| Original Caption Released with Image |
Bora Bora, Tahaa, and Raiatea (top to bottom) are Polynesian Islands about 220 kilometers (135 miles) west-northwest of Tahiti in the South Pacific. Each of the islands is surrounded by a coral reef and its associated islets ("motus") that enclose a lagoon. Actually, as seen here, Tahaa and Raiatea are close enough together to share a common lagoon and reef. These islands are volcanic in origin and were built up from the sea floor by lava extrusions millions of years ago. None is now active, and all are deeply eroded. This display compares three differing "views from space" of these islands. On the left, an image from the Landsat 7 satellite shows the islands as they might have appeared to an astronaut in orbit in 1999 (but a little sharper and with atmospheric haze suppressed). In the middle is an image created from data gathered by the third-generation Shuttle Imaging Radar (SIR-C), flown in 1994. On the right is a graphic illustrating elevation data gathered by the Shuttle Radar Topography Mission (SRTM) in 2000. Each of these images shows very different information as compared to the other two. Landsat sees clouds, which are almost always above these islands, blocking the view of the terrain. It also readily sees through shallow water down to the reefs. SIR-C sees the waves and other effects of winds upon the ocean surface. It does not look through water to see the reefs, but it clearly separates land and water. It also provides a bolder (but distorted) view of the islands' topographic patterns. With the ability of radar to see through clouds and provision of its own illumination, the SIR-C view is not limited by clouds nor their shadows. SRTM was designed to provide new information that is missing in the Landsat and SIR-C views. Specifically, SRTM created the world's first near-global, detailed elevation model. Natural topographic shading in Landsat imagery and radar topographic shadowing of SIR-C give some evidence of the shape of the ground but do not actually measure topographic height. They therefore have not fully characterized the three-dimensional shape of landforms. The shape and height of Earth's landforms affects nearly every natural process and human activity that occurs at Earth's surface, including vegetative growth, water supply, transportation, and radio communication. Thus, the new information provided by SRTM is highly valuable in understanding and interacting with our environment. The Landsat image is an enhanced display of natural visible color (Landsat bands 1,2,3 in blue, green, red). As is evident from the cloud shadows, the morning sun shines from the northeast (upper right). The SIR-C image displays the L-band radar data (23.5 centimeter wavelength, vertical transmit and receive) in red, C-band radar data (5.8 centimeter wavelength, vertical transmit and receive) in green, and a difference of the two (L minus C) in blue. Cosmetic color adjustments were used to enhance the green and blue display of land and, water. The "side-looking" transmitted radar illumination was from the northeast as the Space Shuttle Endeavour passed from northwest to southeast on a descending orbit. Two visualization methods were combined to produce the SRTM image: color coding of topographic height plus shading of the topographic model. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Shading was derived by computing topographic slope in the northeast-southwest direction, so that northeast slopes appear bright and southwest slopes appear dark, generally consistent with the Landsat and SIR-C illumination directions. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Size: 73 kilometers (45 miles) by 42 kilometers (26 miles) Location: 16.7 degrees South latitude, 151.5 degrees West longitude Orientation: North toward the top right Image Data: Landsat (left), SIR-C (middle), shaded and colored SRTM elevation (right) Date Acquired: July 20, 1999 (Landsat), October 1994 (SIR-C), February 2000 (SRTM) |
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| General Description |
STS-68 Shuttle Mission Imagery |
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