Use of the Italian-built SHARAD instrument for examining part of Utopia Planitia was prompted by Gordon Osinski at Western University in Ontario, Canada, a co-author of the study. The portion examined by Stuurman and colleagues lies southwest of that long-silent lander. NASA sent the Viking 2 Lander to a site near the center of Utopia in 1976. Utopia Planitia is a basin with a diameter of about 2,050 miles (3,300 kilometers), resulting from a major impact early in Mars' history and subsequently filled. "Where water ice has been around for a long time, we just don't know whether there could have been enough liquid water at some point for supporting microbial life," Holt said. However, some melting can't be ruled out during different climate conditions when the planet's axis was more tilted. If there were a melted layer - which would be significant for the possibility of life on Mars - it would have been evident in the radar scans. "This deposit is probably more accessible than most water ice on Mars, because it is at a relatively low latitude and it lies in a flat, smooth area where landing a spacecraft would be easier than at some of the other areas with buried ice," said Jack Holt of the University of Texas, a co-author of the Utopia paper who is a SHARAD co-investigator and has previously used radar to study Martian ice in buried glaciers and the polar caps. Ice deposits close to the surface are being considered as a resource for astronauts. It represents less than one percent of all known water ice on Mars, but it more than doubles the volume of thick, buried ice sheets known in the northern plains. The name Utopia Planitia translates loosely as the "plains of paradise." The newly surveyed ice deposit spans latitudes from 39 to 49 degrees within the plains. These two images show Shallow Radar (SHARAD) instrument data from two tracks in a part of Mars' Utopia Planitia region where the orbiting, ground-penetrating radar on NASA's Mars Reconnaissance Orbiter detected subsurface deposits rich in water ice.Ĭredit: NASA/JPL-Caltech/Univ. Climate modeling and previous findings of buried, mid-latitude ice indicate that frozen water accumulates away from the poles during high-tilt periods. In cycles lasting about 120,000 years, the tilt varies to nearly twice that much, heating the poles and driving ice to middle latitudes. Mars today, with an axial tilt of 25 degrees, accumulates large amounts of water ice at the poles. She is the lead author of a report in the journal Geophysical Research Letters. "This deposit probably formed as snowfall accumulating into an ice sheet mixed with dust during a period in Mars history when the planet's axis was more tilted than it is today," said Cassie Stuurman of the Institute for Geophysics at the University of Texas, Austin. The Utopia deposit is shielded from the atmosphere by a soil covering estimated to be about 3 to 33 feet (1 to 10 meters) thick. It sublimes into water vapor in the planet's thin, dry atmosphere. The deposit ranges in thickness from about 260 feet (80 meters) to about 560 feet (170 meters), with a composition that's 50 to 85 percent water ice, mixed with dust or larger rocky particles.Īt the latitude of this deposit - about halfway from the equator to the pole - water ice cannot persist on the surface of Mars today. Analyses of data from more than 600 overhead passes with the onboard radar instrument reveal a deposit more extensive in area than the state of New Mexico. Scientists examined part of Mars' Utopia Planitia region, in the mid-northern latitudes, with the orbiter's ground-penetrating Shallow Radar (SHARAD) instrument. This research advances understanding about Mars' history and identifies a possible resource for future astronauts.įrozen beneath a region of cracked and pitted plains on Mars lies about as much water as what's in Lake Superior, largest of the Great Lakes, researchers using NASA's Mars Reconnaissance Orbiter have determined. It was assessed using a radar aboard a NASA spacecraft orbiting Mars. The amount of water in this deposit is about as much as in Lake Superior. Water ice makes up half or more of an underground layer in a large region of Mars about halfway from the equator to the north pole. They found about as much frozen water as the volume of Lake Superior.Ĭredit: NASA/JPL-Caltech/Univ. This vertically exaggerated view shows scalloped depressions in a part of Mars where such textures prompted researchers to check for buried ice, using ground-penetrating radar aboard NASA's Mars Reconnaissance Orbiter.
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