Microbial Life: Mars Gale Crater Favorable, Landing Spot For Curiosity Rover

 

This computer-generated view based on multiple orbital observations shows Mars’ Gale crater as if seen from an aircraft northwest of the crater.

 Image credit: NASA/JPL-Caltech/ASU/UA 

“Mars is firmly in our sights,” said NASA Administrator Charles Bolden. “Curiosity not only will return a wealth of important science data, but it will serve as a precursor mission for human exploration to the Red Planet.”

During a prime mission lasting one Martian year — nearly two Earth years — researchers will use the rover’s tools to study whether the landing region had favorable environmental conditions for supporting microbial life and for preserving clues about whether life ever existed.

“Scientists identified Gale as their top choice to pursue the ambitious goals of this new rover mission,” said Jim Green, director for the Planetary Science Division at NASA Headquarters in Washington. “The site offers a visually dramatic landscape and also great potential for significant science findings.”

 

NASA has selected Gale crater as the landing site for the Mars Science Laboratory mission. 

Image credit: NASA/JPL-Caltech/ASU 

In 2006, more than 100 scientists began to consider about 30 potential landing sites during worldwide workshops. Four candidates were selected in 2008. An abundance of targeted images enabled thorough analysis of the safety concerns and scientific attractions of each site. A team of senior NASA science officials then conducted a detailed review and unanimously agreed to move forward with the MSL Science Team’s recommendation. The team is comprised of a host of principal and co-investigators on the project.

Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock that the rover’s robotic arm collects. A radioisotope power source will provide heat and electric power to the rover. A rocket-powered sky crane suspending Curiosity on tethers will lower the rover directly to the Martian surface.

The portion of the crater where Curiosity will land has an alluvial fan likely formed by water-carried sediments. The layers at the base of the mountain contain clays and sulfates, both known to form in water.

“One fascination with Gale is that it’s a huge crater sitting in a very low-elevation position on Mars, and we all know that water runs downhill,” said John Grotzinger, the mission’s project scientist at the California Institute of Technology in Pasadena, Calif. “In terms of the total vertical profile exposed and the low elevation, Gale offers attractions similar to Mars’ famous Valles Marineris, the largest canyon in the solar system.”

Curiosity will go beyond the “follow-the-water” strategy of recent Mars exploration. The rover’s science payload can identify other ingredients of life, such as the carbon-based building blocks of biology called organic compounds. Long-term preservation of organic compounds requires special conditions. Certain minerals, including some Curiosity may find in the clay and sulfate-rich layers near the bottom of Gale’s mountain, are good at latching onto organic compounds and protecting them from oxidation.

“Gale gives us attractive possibilities for finding organics, but that is still a long shot,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at agency headquarters. “What adds to Gale’s appeal is that, organics or not, the site holds a diversity of features and layers for investigating changing environmental conditions, some of which could inform a broader understanding of habitability on ancient Mars.”

Rock Layers in Lower Mound in Gale Crater
This oblique view of the lower mound in Gale crater shows layers of rock that preserve a record of environments on Mars. Here, orbiting instruments have detected signatures of both clay minerals and sulfate salts, with more clay minerals apparent in the foreground of this image and fewer in higher layers. This change in mineralogy may reflect a change in the ancient environment in Gale Crater.

Mars scientists have several important hypotheses about how these minerals may reflect changes in the amount of water on the surface of Mars. The Mars Science Laboratory rover, Curiosity, will use its full suite of instruments to study these minerals to provide insights into these ancient Martian environments. These rocks are also a prime target in the search for organic molecules since these past environments may have been habitable — able to support microbial life. Scientists will study how organic molecules, if present, vary with mineralogical variations in the layers to understand how they formed and what influences their preservation.

The smaller hills in this view may provide clues to the modern water cycle on Mars. They contain sulfate salts that have water in them, and as temperatures warm into summer, some of that water may be released to the atmosphere. As temperatures cool, they may absorb water from the atmosphere. The Mars Science Laboratory team will investigate how water is exchanged between these minerals and the atmosphere, helping us understand Mars’ modern climate. The hills are particularly useful for this investigation because different parts of the hills are exposed to different amounts of sunlight and thus to different temperatures. Curiosity will be able to compare the water in these contrasting areas as part of its investigations.

This three-dimensional perspective view was created using visible-light imaging by the High Resolution Imaging Science Experiment camera on NASA’s Mars Reconnaissance Orbiter and the High Resolution Stereo Camera on the European Space Agency’s Mars Express orbiter. Three-dimensional information was derived by stereo analysis of image pairs. The vertical dimension is not exaggerated. Color information is derived from color imaging of portions of the scene by the High Resolution Imaging Science Experiment camera.

Image credit: NASA/JPL-Caltech/ESA/UA

The Mars Science Laboratory spacecraft is being prepared for launch during the period Nov. 25 to Dec. 18, 2011. In a prime mission lasting one Martian year — nearly two Earth years — after landing, researchers will use the rover’s tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and for preserving clues about whether life existed.

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory and Mars Reconnaissance Orbiter projects for NASA’s Science Mission Directorate in Washington.

The University of Arizona, Tucson, operates the High Resolution Science Imaging Experiment. The European Space Operations Centre in Darmstadt, Germany, operates the European Space Agency’s Mars Express mission. The High Resolution Stereo Camera was developed by a group with leadership at the Freie Universitat Berlin.

The rover and other spacecraft components are being assembled and are undergoing final testing. The mission is targeted to launch from Cape Canaveral Air Force Station in Florida between Nov. 25 and Dec. 18. NASA’s Jet Propulsion Laboratory in Pasadena manages the mission for the agency’s Science Mission Directorate in Washington. JPL is a division of Caltech.

NASA has chosen a landing site inside Gale crater for the Mars Science Laboratory mission, which is scheduled to land on the Red Planet in August 2012. The Mars rover Curiosity will set down at the foot of a mountain of stacked layers and drill into rocks for clues about Mars’ environmental history. Gale spans 96 miles (154 kilometers) in diameter and holds a mountain rising higher from the crater floor than Mt. Rainier rises above Seattle. Layering in the mound suggests it is the surviving remnant of an extensive sequence of deposits. MSL is scheduled for launch in November.

Contacts and sources:
Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif.