NASA - National Aeronautics and Space Administration

NASA's Phoenix Mars Lander has launched from Florida's Cape Canaveral Air Force Station aboard a Delta II rocket.
Image credit: NASA

Nestled in the heart of California’s Silicon Valley, NASA Ames is supporting the Phoenix Mars Mission with four scientists: Chris McKay, science co-investigator; Carol Stoker, science lead for the Biological Potential Science Working Group; Aaron Zent, science lead for the Thermal Electrical Conductivity Probe; and Richard Quinn, who works on the Microscopy, Electrochemistry, Conductivity Analyzer (MECA) payload.

As a co-investigator for the science portion of the Phoenix mission, McKay is analyzing all of Phoenix’s instrument measurement data for the surface of Mars in the circumpolar region where Phoenix landed. Phoenix Mission scientists targeted this area of Mars as the most likely place to take samples of the Red Planet’s surface based on the identification of sub-surface ice by the Mars Odyssey orbiter in 2002. The lander is equipped with a special robotic arm and scoop that scrapes below the surface and delivers soil and ice samples onto the platform where its scientific instruments analyze the material and deliver data to the scientists. McKay and his fellow science team members are specifically looking at the chemistry of the soil and ice and searching for organic materials. The scientists have two main objectives: to study the history of water in the Martian arctic and to search for evidence of a habitable zone and assess the biological potential of the ice-soil boundary. McKay’s extensive experience in Antarctica helps him interpret data gleaned from Mars.

“The high elevations in the dry valleys of Antarctica are the only place on Earth where ice-cemented ground exchanges with the surface purely as water vapor rather than as liquid. This is what we expect on Mars,” McKay explained. “Nonetheless, there are viable bacteria in that ground ice. An example of life without bulk liquid water, just the thin film that forms on ice. Maybe, this could have happened on Mars.”

Stoker, as the science leader of the Biological Potential Science Working Group, is directing a team studying whether the environment may have been capable of supporting life in either the recent or distant past. The team is searching for evidence of a habitable zone and assessing the biological potential of the ice-soil boundary. Stoker has designed various ‘dig strategies’ for the lander’s robotic arm to determine the potential for habitability within the Martian soil. She collaborated with Ames’ computer scientists Larry Edwards and Leslie Keely to develop terrain visualizations for mission scientists planning the digs.

As the science lead for the Thermal Electrical Conductivity Probe, part of the MECA payload, Zent is measuring the temperature, thermal conductivity, heat capacity and moisture content of the Martian soil. The probe is mounted at the end of the robotic arm and measures the conduction of heat between the Martian surface and its ice table, as well as any migration of water molecules through the soil that might result from temperature variations. The instrument provides information about the possibility of thin films of liquid water in the Martian soil, and provides measurements needed to determine the amount of water in the soil in past climate epochs. The energy and water transported between the planet’s surface and its underlying ice table plays an important part in the potential habitability of the high-latitude ground ice over long time periods. Zent also participates in mission operations, helping make the strategic and tactical decisions about lander resources and activities.

“Phoenix is the first Mars mission conceived and executed specifically to identify and characterize potential habitats. What we learn here will influence our thinking about the habitability of Mars for the coming decades,” Zent observed.

Ames’ scientific participation in the Phoenix Mission also includes Richard Quinn of the SETI Institute, who works with the Wet Chemistry Laboratory instrument, part of the MECA payload. The instrument performs electrochemistry analysis of the Martian soil to determine its chemical composition and reactivity. This instrument is particularly sensitive to chemicals that dissolve in water and therefore may be available for consumption.
Deborah Robin Croft
NASA's Ames Research Center, Moffett Field, Calif.
650-604-6787
Deborah.R.Croft@nasa.gov

Rachel Prucey
NASA's Ames Research Center, Moffett Field, Calif.
650-604-0643
Rachel.L.Prucey@nasa.gov