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Pilot Neil Armstrong with X-
…
| Photo Description |
NASA test pilot Neil Armstrong is seen here next to the X-15 ship #1 (56-6670) after a research flight. Neil A. Armstrong joined the National Advisory Committee for Aeronautics (NACA) at the Lewis Flight Propulsion Laboratory (later NASA?s Lewis Research Center, Cleveland, Ohio, and today the Glenn Research Center) in 1955. Later that year, he transferred to the NACA?s High-Speed Flight Station (today, NASA?s Dryden Flight Research Center) at Edwards Air Force Base in California as an aeronautical research scientist and then as a pilot, a position he held until becoming an astronaut in 1962. He was one of nine NASA astronauts in the second class to be chosen. As a research pilot Armstrong served as project pilot on the F-100A and F-100C aircraft, F-101, and the F-104A. He also flew the X-1B, X-5, F-105, F-106, B-47, KC-135, and Paresev. He left Dryden with a total of over 2450 flying hours. He was a member of the USAF-NASA Dyna-Soar Pilot Consultant Group before the Dyna-Soar project was cancelled, and studied X-20 Dyna-Soar approaches and abort maneuvers through use of the F-102A and F5D jet aircraft. Armstrong was actively engaged in both piloting and engineering aspects of the X-15 program from its inception. He completed the first flight in the aircraft equipped with a new flow-direction sensor (ball nose) and the initial flight in an X-15 equipped with a self-adaptive flight control system. He worked closely with designers and engineers in development of the adaptive system, and made seven flights in the rocket plane from December 1960 until July 1962. During those fights he reached a peak altitude of 207,500 feet in the X-15-3, and a speed of 3,989 mph (Mach 5.74) in the X-15-1. Armstrong was born August 5, 1930, in Wapakoneta, Ohio. He attended Purdue University, earning his Bachelor of Science degree in aeronautical engineering in 1955. During the Korean War, which interrupted his engineering studies, he flew 78 combat missions in F9F-2 jet fighters. He was awarded the Air Medal and two Gold Stars. He later earned a Master of Science degree in aerospace engineering from the University of Southern California. Armstrong has a total of 8 days and 14 hours in space, including 2 hours and 48 minutes walking on the Moon. In March 1966 he was commander of the Gemini 8 orbital space flight with David Scott as pilot?the first successful docking of two vehicles in orbit. On July 20, 1969, during the Apollo 11 lunar mission, he became the first human to set foot on the Moon. From 1969 to 1971 he was Deputy Associate Administrator for Aeronautics at NASA Headquarters, and resigned from NASA in August 1971 to become Professor of Engineering at the University of Cincinnati, a post he held until 1979. He became Chairman of the Board of Cardwell International, Ltd., in Lebanon, Ohio, in 1980 and served in that capacity until 1982. During the years 1982-1992, Armstrong was chairman of Computing Technologies for Aviation, Inc., in Charlottesville,, Virginia. From 1981 to 1999, he served on the board of directors for Eaton Corp. He served as chairman of the board of AIL Systems, Inc. of Deer Park, New York, until 1999 and in 2000 was elected chairman of the board of EDO Corp., a manaufacturer of electronic and mechanical systems for the aerospace, defense and industrial markets, based in New York City. From 1985 to 1986, Armstrong served on the National Commission on Space, a presidential committee to develop goals for a national space program into the 21st century. He was also Vice Chairman of the committee investigating the Space Shuttle Challenger disaster in 1986. During the early 1990s he hosted an aviation documentary series for television entitled First Flights. |
| Project Description |
The X-15 was a rocket-powered aircraft 50 ft long with a wingspan of 22 ft. It was a missile-shaped vehicle with an unusual wedge-shaped vertical tail, thin stubby wings, and unique fairings that extended along the side of the fuselage. The X-15 weighed about 14,000 lb empty and approximately 34,000 lb at launch. The XLR-99 rocket engine, manufactured by Thiokol Chemical Corp., was pilot controlled and was capable of developing 57,000 lb of rated thrust (actual thrust reportedly climbed to 60,000 lb). North American Aviation built three X-15 aircraft for the program. The X-15 research aircraft was developed to provide in-flight information and data on aerodynamics, structures, flight controls, and the physiological aspects of high-speed, high-altitude flight. A follow-on program used the aircraft as a testbed to carry various scientific experiments beyond the Earth's atmosphere on a repeated basis. For flight in the dense air of the usable atmosphere, the X-15 used conventional aerodynamic controls such as rudder surfaces on the vertical stabilizers to control yaw and canted horizontal surfaces on the tail to control pitch when moving in synchronization or roll when moved differentially. For flight in the thin air outside of the appreciable Earth's atmosphere, the X-15 used a reaction control system. Hydrogen peroxide thrust rockets located on the nose of the aircraft provided pitch and yaw control. Those on the wings provided roll control. Because of the large fuel consumption, the X-15 was air launched from a B-52 aircraft at 45,000 ft and a speed of about 500 mph. Depending on the mission, the rocket engine provided thrust for the first 80 to 120 sec of flight. The remainder of the normal 10 to 11 min. flight was powerless and ended with a 200-mph glide landing. Generally, one of two types of X-15 flight profiles was used: a high-altitude flight plan that called for the pilot to maintain a steep rate of climb, or a speed profile that called for the pilot to push over and maintain a level altitude. The X-15 was flown over a period of nearly 10 years--June 1959 to Oct. 1968--and set the world's unofficial speed and altitude records of 4,520 mph (Mach 6.7) and 354,200 ft (over 67 mi) in a program to investigate all aspects of piloted hypersonic flight. Information gained from the highly successful X-15 program contributed to the development of the Mercury, Gemini, and Apollo manned spaceflight programs, and also the Space Shuttle program. The X-15s made a total of 199 flights and were manufactured by North American Aviation. X-15-1, serial number 56-6670, is now located at the National Air and Space Museum, Washington DC. North American X-15A-2, serial number 56-6671, is at the United States Air Force Museum, Wright-Patterson AFB, Ohio. The X-15-3, serial number 56-6672, crashed on 15 November 1967, resulting in the death of Maj. Michael J. Adams. |
| Photo Date |
1960s |
|
Groundwater May be Source fo
…
PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
|
Groundwater May be Source fo
…
PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
|
Groundwater May be Source fo
…
PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
|
Groundwater May be Source fo
…
PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
|
Groundwater May be Source fo
…
PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
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Groundwater May be Source fo
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PIA09031
Sol (our sun)
Mars Orbiter Camera
| Title |
Groundwater May be Source for Erosion in Martian Gullies |
| Original Caption Released with Image |
Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough. Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues, carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies. The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water. Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here. Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera. For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html [ http://www.msss.com/mgs/moc/index.html ]., layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide. Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005. Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater, the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006. The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, |
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