Phoenix Mars Lander

Professor Sam Kounaves and his students at Ihfts University were filled with excitement as their Wet Chemistry Laboratory experiment aboard the Phoenix Mars Lander returned a stream of information about the composition of Martian soil scooped up hy a robotic arm. The arm delivered 1 gram of soil through a sieve into a lieakei fitted with a suite of electrochemical sensors described in Chapter 15. Aqueous solution added to the beaker leached soluble salts from the soil while sensors measured ions appearing in the liquid. Unlike other ions, sulfate was measured hy a precipitation titration with Ba ... 

Barium sulfate precipitation titration from Phoenix Mars Lander. [Data from Reference 1, courtesy S. Kounaves, Tufts University.)... 

Hach of four Wet Chemistry Laboratories on the Phoenix Mars Lander shown at the opening of Chapter 6 was equipped with 23 electrochemical sensors, of which 15 were ion-selective electrodes similar to those discussed in this chapter. The robotic arm delivered soil through the sieve into the beaker compartment. Then aqueous solution was added to leach soluble salts from the soil. Sensors measured ions appearing in the liquid. 

In 2008, a microscope attached to the National Aeronautics and Space Administration s Phoenix Mars Lander took a photograph of a single particle of the incredibly fine red dust that swirls around Mars and forms its soil. Dust particles on Mars are about 100 nanometers, about one-thousandth the width of a human hair—or even smaller. 

Geotz, Walter. Phoenix on Mars. American Scientist 98, no. 1 (January, 2010) 40-47. A comprehensive article covering the scientific results from NASA s Phoenix Mars Lander. 

A The Phoenix Mars Lander is looking for evidence of life in frozen water that lies below the surface of Mars s north polar region. 

Spirit rovers) included mainly X-ray spectrometers and imagers. It was not until 2007 with the launch of the Phoenix Mars lander mission that the first electroan-alytical measurement system was delivered to the martian surface. Here we present the historical context of the first electroanalyses on Mars, an overall description of the electrochemically based sensors that were part of the Phoenix Wet Chemistry Laboratory (WCL), the results of the martian soil analyses and their implications, the most recent Earth-based experiments, and a preview of the next-generation electroanalytical instruments currently in development for upcoming missions to Mars and beyond. 

Kounaves SP, HechtMH, Kapit J etal(2010) Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission Data analysis and results. J Geophys Res 115 EOOE10. doi 10. 1029/2009JE003424... 

Later successful U.S. landers included the Mars Pathfinder lander/rover mission (which utilized air bags rather than retro-rockets during the last phase of its landing) and the Phoenix, which studied the geologic history of water on Mars, its involvement in Martian climate change, and the planet s past or future habitability. 

The NASA supported development of the in situ Chemical Analysis Laboratory and Sensor Array (CHEMSENS) is based on the Phoenix WCL and will provide for real-time investigation of the soil on Mars and similar planetary settings. Though the Phoenix mission is viewed as highly successful and is stiU providing results years after the end of the mission, it was clear that improvements could be made for future missions. These included (1) the number of individual WCL units, (2) an increased number of sensors in the array, and (3) sensor redundancy. Incorporating these improvements resulted in a scalable payload of mini-WCL units with a movable gantry for sample delivery and various actuator assemblies. This will allow for a payload of a few or a hundred WCL units to be incorporated into a lander or rover. 

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