2000 SPACE SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| DRAMATIC MARS IMAGES PEER INTO PLANET'S PAST | G00-026 | 03/10/00 | 00:19:03 | On the day Hollywood launches millions of moviegoers on a fictional trip to Mars, NASA releases the latest real images to come from a spacecraft actually orbiting Earth's sibling planet. Using a variety of techniques and instruments, scientists working with the Mars Global Surveyor spacecraft have been able to generate wide area images of the Martian surface, providing first person point-of-view perspectives as if one were flying in a plane above the surface. But the real excitement is scientific, with researchers releasing a new map of the planet's crust based on more than 300 million measurements taken from an orbiting probe. When used in conjunction with precise new maps of the planet's gravitational field and topography, experts are gaining vastly better understandings how Mars is put together. This new research is helping the space agency prepare for future missions to The Red Planet, while gaining a clearer understanding of the planet's past and future.
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TAPE CONTENTS: |
| ITEM (1): REVEALING A PLANET - Researchers using data collected by the Mars Orbiter Laser Altimeter (MOLA) and a clever radio science experiment combined their findings and generated an entirely new map of the planet, providing the first measurements of
Mars' crustal thickness. These measurements were inferred by the combination of two observational data sets, namely surface topography and the planet’s gravitational field. |
| ITEM (2): REVEALING A PLANET - TOPOGRAPHY - The first of these maps, shown here wrapped around the Martian globe, depicts topography, or surface features. In these images, white and red features are highest in relative elevation, while green and blue areas are lowest. These images were made possible by data from the Mars Orbiter Laser Altimeter, which bounced a laser off the surface of the planet and calculated the distance traveled by the beam of light.
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| ITEM (3): REVEALING A PLANET - GRAVITATIONAL FIELD - The second map portrays observed data describing Mar's gravitational field. Seen here, white and red areas depict regions with the strongest gravitational force, while green and blue areas are the weakest. These images were generated by data reported by the Radio Science Experiment.
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| ITEM (4): REVEALING A PLANET - A MAP OF THE CRUST - The final map is similar to the first two, but with an important distinction: the data used to create it are based on inferences generated by combining the topographical and gravitational maps. In this image, blues indicate thin areas of crust, while red and white indicate thicker areas. This synthetic visualization clearly shows how comparatively thin the crust is in the Northern Hemisphere versus the Southern Hemisphere. The moho is the region where the crust and mantle meet. By determining the thickness of the crust and generating a map of the moho, scientists are developing a better understanding
about the interior structure of Mars. Project researchers say this adds evidence to the theory that there may have been an unusual type of convective cooling on Mars when it was a younger planet. Using this new sub-surface, interior view, scientists have a window into Mars' geologic past and the forces that shaped the surface we see today.
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| ITEM (5): AN ASYMMETRICAL PLANET - The Martian Mantle Measurements of Mars’s gravity field, topography, and the subsequently derived crustal map show the Southern Hemisphere to be significantly thicker than the north. In this visualization, we show a cutaway of the planet’s skin, with surface features and crustal thickness displayed in relative sizes to each other. Notice how the crust on the right side of the cross section appears significantly thicker than the crust on the left. |
| ITEM (6): SUBSURFACE WATER CHANNELS - Evidence suggests that rapid heat flow in the Northern Hemisphere produced a wide lowland area there, encouraging the formation of channels, which could have sluiced water resources into a large basin, even an early ocean. These images show a network of channels draining from the giant Valles Marineris into the wide, flat area of the north. These channels yawn nearly 200 kilometers wide and run more than 1650 kilometers long.
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| ITEM (7): A WORKING THEORY ABOUT AN UNUSUAL RADIATOR - The dramatic asymmetry in structure suggests that the planet did not cool evenly for reasons that are still somewhat unclear. The low-lying terrain of the Northern Hemisphere suggests that Mars might have released more heat from the north than the south. In other words, the north might have taken longer to cool. With much of the planet's heat being radiated in the north, the terrain there formed a smoother, lower average topography, and therefore a thinner crust.
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| ITEM (8): MAPPING MARTIAN GRAVITY - Researchers developed this map of the planet's gravity with the simply named Radio Science Experiment. It worked like this: slight variations in the expected time required for radio signals to travel between Earth and Mars pointed to inconsistencies in the planet's gravitational field. Those inconsistencies were deduced to be what caused the Surveyor's orbit to "wiggle" as it wheeled around the Red Planet, thus causing the transmission time variations.
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| ITEM (9): MEASURING MARS WITH MOLA - The Mars Orbiter Laser Altimeter (MOLA) has fired a precise beam of light at the planet it's circling more than 300 million times. By measuring the two-way travel time of that laser as it flashes down to the surface and then as its reflected back up to the orbiter, a precise altitude scheme can be determined and compiled, which then can be converted into a detailed topographical map.
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| ITEM (10): A PLANET OF SUPERLATIVES - VALLES MARINERIS - Valles Marineris is the longest valley in the solar system and remains an area of intense interest for those who study Mars. As it wraps around a vast stretch of the planet’s center, it appears to drain from the Tharsis and Chryse highlands directly into the northern lowland regions.
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| ITEM (11): A PLANET OF SUPERLATIVES - HELLAS IMPACT BASIN - This enormous hole in the Red Planet is believed to be the result of a violent collision by an interstellar body with the surface of Mars billions of years ago. And it is enormous: Hellas is more than nine kilometers deep and at 2100 kilometers across, it could swallow almost half of the United States. Crater ejecta stretches out from the center of the bowl more than 4000 kilometers from the center of the basin, with a ring of blast material lining the bowl as high as 2 kilometers.
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| ITEM (12): A PLANET OF SUPERLATIVES - OLYMPUS MONS - At more than two and a half times the height of Mt. Everest, Olympus Mons is indisputably the king of the solar system's peaks. At the 25-kilometer high summit, one would easily see the curvature of Mars. The mountain rises so far above the surface that it actually leaves all but 5% of the Martian atmosphere behind. The cratered caldera caps a mountain bulge that stretches almost 550 kilometers east to west, covering an area roughly the size of Arizona.
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| ITEM (13): THE MARTIAN NORTH POLE - Both the northern and southern ice caps vary in size as seasons change on Mars. The permanent northern cap is believed to be made mostly of frozen water while the southern cap is believed to be made of frozen carbon dioxide and water. Shown here the northern ice cap extends over a sizeable portion of the planet's pole, rippling and folding as ice and snow merge together. It's non-seasonally affected size is several times greater than its southern counterpart.
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| ITEM (14): MAGNETIC FIELD OSCILLATIONS - Mars does not show the same kind of magnetic field Earth. But evidence collected by the Mars Global Surveyor (MGS) indicates that the planet may have had a global magnetic field, generated by an internal geological dynamo. Evidence suggest that the planet's magnetic field reversed direction, or flipped, several times throughout Martian history as mantle and core conditions changed.
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| ITEM (15): THE MARS GLOBAL SURVEYOR - By collecting information about the planet?s topography, composition, atmosphere, and more, MGS is enabling scientists to build a comprehensive model of Mars in order to understand it better. NASA contractor Lockheed Martin built the Mars Global Surveyor at their facility in Denver. Fully loaded with fuel, the tiny probe weighed only 1060 kilograms (2,342 pounds) on November 7, 1996 when a Delta-7925 rocket launches it to Mars.
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| ITEM (16): B-ROLL - Scientists at work.
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| ITEM (17): INTERVIEW EXCERPTS WITH DR. DAVID SMITH
PRINCIPLE INVESTIGATOR, MARS ORBITING LASER ALTIMETER
Scientists at work.
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Space Science Gallery