National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
News & Events
NASA Mission Finds New Clues to Guide the Search for Life on Mars
NASA Mission Finds New Clues to Guide the Search for Life on Mars
20 Mar 2008
(Source: NASA)

WASHINGTON - NASA's Mars Odyssey orbiter has found evidence of salt deposits. These deposits point to places where water once was abundant and where evidence might exist of possible Martian life from the Red Planet's past.

A team led by Mikki Osterloo of the University of Hawaii, Honolulu, found approximately 200 places on southern Mars that show spectral characteristics consistent with chloride minerals. Chloride is part of many types of salt, such as sodium chloride or table salt. The sites range from about half of a square mile to 25 times that size.

"They could come from groundwater reaching the surface in low spots," Osterloo said. "The water would evaporate and leave mineral deposits, which build up over years. The sites are disconnected, so they are unlikely to be the remnants of a global ocean."

Scientists used Odyssey's Thermal Emission Imaging System, a camera designed and operated by Arizona State University, Tempe, to take images in a range of visible light and infrared wavelengths.

Thermal infrared wavelengths are useful for identifying different mineral and rock types on the Martian surface. Osterloo found the sites by looking through thousands of images processed to reveal, in false colors, compositional differences on the Martian surface.

Plotted on a Mars map, the chloride sites appear only in the southern highlands, the most ancient rocks on Mars. Osterloo and seven co-authors report the findings in this week's issue of the journal Science.

"Many of the deposits lie in basins with channels leading into them," said Philip Christensen, co-author and principal investigator for the camera at Arizona State University. "This is the kind of feature, like salt-pan deposits on Earth, that's consistent with water flowing in over a long time."

Scientists think the salt deposits formed approximately 3.5 to 3.9 billion years ago. Several lines of evidence suggest Mars then had intermittent periods with substantially wetter and warmer conditions than today's dry, frigid climate.

Scientists looking for evidence of past life on Mars have focused mainly on a handful of places that show evidence of clay or sulfate minerals. Clays indicate weathering by water, and sulfates may have formed by water evaporation. The new research, however, suggests an alternative mineral target to explore for biological remains.

"By their nature, salt deposits point to a lot of water, which potentially could remain standing in pools as it evaporates." said Christensen. "That's crucial. For life, it's all about a habitat that endures for some time."

Whether life ever has existed on Mars is the biggest scientific question driving Mars research. On Earth, salt is good at preserving organic material. Bacteria have been revived in the laboratory after being preserved in salt deposits for millions of years.

"This discovery demonstrates the continuing value of the Odyssey science mission, now entering its seventh year. The more we look at Mars, the more fascinating a place it becomes," said Jeffrey Plaut, Odyssey project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"This is a wonderful and scientifically exciting result obtained from a relatively low cost NASA Mars orbiter mission which still has years of life left.," said Alan Stern, associate administrator for NASA's Science Mission Directorate in Washington. "Hold on to your hats, more exciting results from Mars are sure to be coming."

For additional information about Odyssey, visit:

Dwayne Brown Headquarters, Washington

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.

Robert Burnham
Arizona State University, Tempe

Tara Hicks-Johnson
University of Hawaii, Manoa
808- 956-3151

RELEASE : 08-084

News Archive Search  Go!
Show  results per page
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writers: Courtney O'Connor and Bill Dunford
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> NASA Advisory Council
> Open Government at NASA
Last Updated: 7 Jul 2010