Two University of Tennessee, Knoxville, professors are searching for potential habitats for life on Mars. Linda Kah and Jeffrey Moersch, associate professors of earth and planetary sciences, are an integral part of a NASA team working on the Curiosity rover, which launched from the Kennedy Space Center on November 26 and is now hurtling toward the Red Planet.

Curiosity is not scheduled to land until August 6, 2012. When it does, it will search for clues to whether the planet has ever had an environment capable of sustaining life, such as liquid or frozen water, organic compounds, and other chemical ingredients related to life.

Kah, Moersch, and the rest of the science team will select targets for the rover to investigate each day and choose which instruments will examine modern Martian soils and inspect sedimentary rocks that might serve as a time capsule of Mars' transition from a warm, wet planet to a cold, dry one.

"The Curiosity has a lot of cutting-edge technology for us to conduct our work," said Kah. "It is like a field geologist with an analytical laboratory on her back."

Kah is part of a camera team that will search for rocks with features that might indicate the presence of microbial life in the planet's past. The rover will collect soil material and powdered rock samples using its robotic arm to gather, strain, and transfer them into the rover's analytical system.

Kah will then use an instrument capable of detecting both organic molecules and the isotopic signatures often left in rocks by microbial metabolisms.

Kah has studied the role of microbial life in the formation of some of Earth's earliest rocks in such remote places as the West African Sahara desert and Arctic Canada.

"For years, I have used the same set of observations that Curiosity will be making to investigate ancient rocks," said Kah, who has been a co-investigator on the mission for seven years.

"I will be looking for microscopic details visible in layers of rock, unusual assemblages of minerals, and the chemistry of both mineral and organic material to decipher clues to the presence of life, but this time I will be doing it on Mars."

Moersch is searching for hydrogen-another ingredient important for life-in the form of water or clay and sulfate minerals. He and the team will use the rover's neutron detector, the same technology oil companies use to sniff out hydrocarbons for drilling holes, to search for hydrogen-bearing materials and other geochemical anomalies in the Martian surface.

"If the neutron detector turns up something that is potentially interesting in a given location, we may choose to spend some additional time to investigate that location with the rover's other instruments, including sampling the subsurface with a small drill," said Moersch, who worked on five previous missions to Mars, including the Spirit and Opportunity rovers.

The process is painstakingly slow. The rover likely will cover only a few hundred meters on a good day, and the mission will not conclude until at least 2014. Still the scientists are certain their hard work will pay off.

"I expect that we will find evidence for the building blocks of life, although that is a far cry from actually finding evidence for life," said Kah.

"Personally, I am more excited by the opportunity to ask a whole set of higher-order questions about what the Martian surface was like and how it might have changed through time."