Tag Archives: Mars

NASA Rover Finds Conditions Once Suited for Ancient Life on Mars

An analysis of a rock sample collected by NASA’s Curiosity rover shows ancient Mars could have supported living microbes.  Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — some of the key chemical ingredients for life — in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet last month.

“A fundamental question for this mission is whether Mars could have supported a habitable environment,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington. “From what we know now, the answer is yes.”

Clues to this habitable environment come from data returned by the rover’s Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. The data indicate the Yellowknife Bay area the rover is exploring was the end of an ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable conditions for microbes. The rock is made up of a fine grain mudstone containing clay minerals, sulfate minerals and other chemicals. This ancient wet environment, unlike some others on Mars, was not harshly oxidizing, acidic, or extremely salty.

The patch of bedrock where Curiosity drilled for its first sample lies in an ancient network of stream channels descending from the rim of Gale Crater. The bedrock also is fine-grained mudstone and shows evidence of multiple periods of wet conditions, including nodules and veins.

Curiosity’s drill collected the sample at a site just a few hundred yards away from where the rover earlier found an ancient streambed in September 2012.

“Clay minerals make up at least 20 percent of the composition of this sample,” said David Blake, principal investigator for the CheMin instrument at NASA’s Ames Research Center in Moffett Field, Calif.

These clay minerals are a product of the reaction of relatively fresh water with igneous minerals, such as olivine, also present in the sediment. The reaction could have taken place within the sedimentary deposit, during transport of the sediment, or in the source region of the sediment. The presence of calcium sulfate along with the clay suggests the soil is neutral or mildly alkaline.

Scientists were surprised to find a mixture of oxidized, less-oxidized, and even non-oxidized chemicals providing an energy gradient of the sort many microbes on Earth exploit to live. This partial oxidation was first hinted at when the drill cuttings were revealed to be gray rather than red.

“The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” said Paul Mahaffy, principal investigator of the SAM suite of instruments at NASA’s Goddard Space Flight Center in Greenbelt, Md.

An additional drilled sample will be used to help confirm these results for several of the trace gases analyzed by the SAM instrument.

“We have characterized a very ancient, but strangely new ‘gray Mars’ where conditions once were favorable for life,” said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena, Calif. “Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting discoveries ahead of us in the months and years to come.”

Scientists plan to work with Curiosity in the Yellowknife Bay area for many more weeks before beginning a long drive to Gale Crater’s central mound, Mount Sharp. Investigating the stack of layers exposed on Mount Sharp, where clay minerals and sulfate minerals have been identified from orbit, may add information about the duration and diversity of habitable conditions.

NASA’s Mars Science Laboratory Project has been using Curiosity to investigate whether an area within Mars’ Gale Crater ever has offered an environment favorable for microbial life. Curiosity, carrying 10 science instruments, landed seven months ago to begin its two-year prime mission. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the project for NASA’s Science Mission Directorate in Washington.

NASA Mission Helps Craft 3-D Image Of Buried Mars Flood Channels

This illustration schematically shows where the Shallow Radar instrument on NASA's Mars Reconnaissance Orbiter detected flood channels that had been buried by lava flows in the Elysium Planitia region of Mars. Marte Vallis consists of multiple perched channels formed around streamlined islands. These channels feed a deeper and wider main channel. In this illustration, the surface has been elevated, and scaled by a factor of one to 100 for clarity. The color scale represents the elevation of the buried channels relative to a Martian datum, or reference elevation. The reason the values are negative is because the elevation of the surface of Mars in this region is also a negative -- below average global elevation.  Credit: NASA/JPL-Caltech/Sapienza University of Rome/Smithsonian Institution/USGS

SIllustration  shows where the Shallow Radar instrument detected flood channels that had been buried by lava flows in the Elysium Planitia region of Mars.

NASA’s Mars Reconnaissance Orbiter (MRO) has provided images allowing scientists for the first time to create a 3-D reconstruction of ancient water channels below the Martian surface.

The spacecraft took numerous images during the past few years that showed channels attributed to catastrophic flooding in the last 500 million years. Mars during this period had been considered cold and dry. These channels are essential to understanding the extent to which recent hydrologic activity prevailed during such arid conditions. They also help scientists determine whether the floods could have induced episodes of climate change.  The estimated size of the flooding appears to be comparable to the ancient mega flood that created the Channeled Scablands in the Pacific Northwest region of the United States in eastern Washington.

The findings are reported in the March 7 issue of Science Express by a team of scientists from NASA, the Smithsonian Institution, and the Southwest Research Institute in Houston.

“Our findings show the scale of erosion that created the channels previously was underestimated and the channel depth was at least twice that of previous approximations,” said Gareth Morgan, a geologist at the National Air and Space Museum’s Center for Earth and Planetary Studies in Washington and lead author on the paper. “This work demonstrates the importance of orbital sounding radar in understanding how water has shaped the surface of Mars.”

The channels lie in Elysium Planitia, an expanse of plains along the Martian equator and the youngest volcanic region on the planet. Extensive volcanism throughout the last several hundred million years covered most of the surface of Elysium Planitia, and this buried evidence of Mars’ older geologic history, including the source and most of the length of the 620-mile-long (1000-kilometer-long) Marte Vallis channel system. To probe the length, width and depth of these underground channels, the researchers used MRO’s Shallow Radar (SHARAD).

Marte Vallis’ morphology is similar to more ancient channel systems on Mars, especially those of the Chryse basin. Many scientists think the Chryse channels likely were formed by the catastrophic release of ground water, although others suggest lava can produce many of the same features. In comparison, little is known about Marte Vallis.

With the SHARAD radar, the team was able to map the buried channels in three dimensions with enough detail to see evidence suggesting two different phases of channel formation. One phase etched a series of smaller branching, or “anastomosing,” channels that are now on a raised “bench” next to the main channel. These smaller channels flowed around four streamlined islands. A second phase carved the deep, wide channels.

“In this region, the radar picked up multiple ‘reflectors,’ which are surfaces or boundaries that reflect radio waves, so it was possible to see multiple layers, ” said Lynn Carter, the paper’s co-author from NASA’s Goddard Space Flight Center in Greenbelt, Md. “We have rarely seen that in SHARAD data outside of the polar ice regions of Mars.”

The mapping also provided sufficient information to establish the floods that carved the channels originated from a now-buried portion of the Cerberus Fossae fracture system. The water could have accumulated in an underground reservoir and been released by tectonic or volcanic activity.

“While the radar was probing thick layers of dry, solid rock, it provided us with unique information about the recent history of water in a key region of Mars,” said co-author Jeffrey Plaut of NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif.

The Italian Space Agency provided the SHARAD instrument on MRO and Sapienza University of Rome leads its operations. JPL manages MRO for NASA’s Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the orbiter and supports its operations.