Volume: 01, Issue: 01
Vertically exaggerated 3-D image of Flaugergues basin, showing extensive dissected terrain in upland regions draining into depressions and smooth, possible lakebed features of the depressions.
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Depth and abundance of depressions, many of which are possible ancient lake features on Mars. Discontinuous stream network.
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Abundance of lake features in the Great Lakes region, USA, selected as an analog site.
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Other Articles in This Issue:
Space InfraRed Telescope Facility to Launch April 18th
Don Pettit Space Chronicles
Professional Development Opportunities
Online Chat with Research Scientist Dr. Daria Schmidt

Evidence of Martian Water System Mounts

For years scientists have observed features on Mars that appear similar to dried-up streambeds existing on Earth. If they are in fact the remains of ancient Martian rivers, this would indicate that they either sprung from a water source beneath the planet’s surface or precipitated from a thicker, more robust atmosphere than the one Mars currently has. Using the Mars Global Surveyor, however, scientists have uncovered evidence that these scattered features may have been part of a large surface system of water on Mars.

“We’ve known for some time that Mars contains lakebed and stream-like surface features, and that many of these stream features run into depressions, then end abruptly,” said Marc G. Kramer, a visiting National Research Council scientist at NASA Ames Research Center in California’s Silicon Valley. Kramer is principal author of a peer-reviewed news article about the study that recently appeared in EOS, a weekly American Geophysical Union publication. “A new aspect of this study shows how these two features link to one another as a single, integrated water network that may have existed on Mars at some time in the past.”

The Mars Global Surveyor carries a laser altimeter used to map elevation levels on the Martian surface. The altimeter bounces a beam of light off of the surface of Mars, timing how long it takes to return. This determines how far away the surface of Mars is from the Mars Global Surveyor. This data is then used to create a three-dimensional topographical map of Mars. By modeling this data through a computer program designed to simulate overland water flow, scientists have discovered depressions in the Martian surface that could be a dried-out system of lakes similar to the Great Lakes in North America.

The study of surface depressions in conjunction with river features provides a more complete picture of a surface water network that may have existed on what must have been a warmer early Mars, according to Christopher Potter, one of Kramer’s co-authors. The researchers excluded fresh impact crater areas during the analysis in order to study older drainage patterns.

“The larger shallow depressions in the main channel system often contain multiple, highly eroded craters and show evidence of stream features in the extensive upland regions draining into them,” Kramer said. These depressions become increasingly shallow downstream, suggesting that increased sedimentation may have been deposited by water or ice that may once have flowed through them.

According to Kramer, scientists are still researching how long and in what sort of climate the water system may have existed. These questions are being investigated by new technology aboard the Mars Odyssey. One of these new instruments is the Thermal Emission Imaging System (THEMIS). Infrared and visible light images captured by THEMIS have revealed a diversity of surface types and features. Nighttime temperature images show complex patterns of rock layers, rocky debris, sand and dust produced by impact cratering, wind erosion, volcanism and deposition.

“The data coming out of the Mars Global Surveyor and Mars Odyssey Mission are quite revealing,” Kramer said. “We were able to study the planet in ways that were previously not possible.”

“With an abundance of ice recently detected just below the surface of Mars, the possibility that life has existed or still may exist may hinge on its past climate and the duration of surface water flows,” Potter said. “Was Mars ever a warm and wet planet, or has it always been cold and dry?”

Jet Propulsion Laboratory in Pasadena, Calif., manages the Mars Global Surveyor and Mars Odyssey missions. The NASA Astrobiology Institute, based at NASA Ames, funded the study that resulted in the peer-reviewed article written by Marc G. Kramer, Christopher Potter, David Des Marais, and David Peterson.

For more information on the Mars Global Surveyor, visit:

For more information on the Mars Odyssey, visit:

For more information on astrobiology, visit:

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