NASA unveils first 3-D map of Mars
May 27, 1999
(CNN) -- An impact basin deep enough to swallow Mount Everest and surprising slopes in Valles Marineris are among the highlights revealed on the first three-dimensional map of the surface of Mars.
The topographical map, based on data gathered by NASA's Mars Global Surveyor, was unveiled by NASA scientists Thursday.
The map gives scientists their first detailed understanding of the relative heights of various geologic features on the red planet, including regions that shaped the flow of water early in Mars' history, NASA said in a statement.
The model also reveals what may be the deepest impact basin in the solar system.
The map was produced using the Surveyor's Laser Altimeter (MOLA) instrument, which fires short pulses of infrared light at the Martian surface and measures the time it takes for the reflected light to return. Given the known orbit of Global Surveyor, the resulting times allow scientists to infer the height of the terrain below with great accuracy.
"This incredible database means that we now know the topography of Mars better than many continental regions on Earth," said NASA's Dr. Carl Pilcher, science director for solar system exploration.
Pilcher said the data will serve as a basic reference book for Mars scientists for many years, and should provide new insights about the planet's geologic history and the ways that water has flowed across its surface during the past four billion years.
Dr. David Smith, the principal investigator for MOLA, said the most curious aspect of the topographic map is the striking difference between the planet's low, smooth northern hemisphere and the heavily cratered southern hemisphere, which sits, on average, about three miles (five km) higher than the north.
The massive Hellas impact basin in the Southern Hemisphere is another striking feature of the map. Nearly six miles (nine km) deep and 1,300 miles (2,100 km) across, the basin is surrounded by a ring of material that rises 1.25 miles (about two km) above the surroundings and stretches out to 2,500 miles (4,000 km) from the basin center.
On a more regional scale, the new data show that the eastern part of the vast Valles Marineris canyon slopes away from nearby outflow channels, with part of it lying a half-mile (about one km) below the level of the outflow channels.
"While water flowed south to north in general, the data clearly reveal the localized areas where water may have once formed ponds, " said Dr. Maria Zuber of the Massachusetts Institute of Technology and Goddard.
Mars Global Surveyor carries five science instruments designed to generate a complete global portrait of Mars and its seasonal changes during a full Martian year, the equivalent of two Earth years.
It is the first mission in NASA's long-term program of Mars exploration known as the Mars Surveyor Program.
Hubble views massive cyclone on Mars
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