Kennda Lynch

Near‐infrared spectroscopy of lacustrine sediments in the Great Salt Lake Desert: An analog study for Martian paleolake basins

The identification and characterization of aqueous minerals within ancient lacustrine environments on Mars are a high priority for determining the past habitability of the red planet. Terrestrial analog studies are useful both for understanding the mineralogy of lacustrine sediments, how the mineralogy varies with location in a lacustrine environment, and for validating the use of certain techniques such as visible–near-infrared (VNIR) spectroscopy. In this study, sediments from the Pilot Valley paleolake basin of the Great Salt Lake desert were characterized using VNIR as an analog for Martian paleolake basins. The spectra and subsequent interpretations were then compared to mineralogical characterization by ground truth methods, including X-ray diffraction, automated scanning electron microscopy, and several geochemical analysis techniques. In general, there is good agreement between VNIR and ground truth methods on the major classes of minerals present in the lake sediments and VNIR spectra can also easily discriminate between clay-dominated and salt-dominated lacustrine terrains within the paleolake basin. However, detection of more detailed mineralogy is difficult with VNIR spectra alone as some minerals can dominate the spectra even at very low abundances. At this site, the VNIR spectra are dominated by absorption bands that are most consistent with gypsum and smectites, though the ground truth methods reveal more diverse mineral assemblages that include a variety of sulfates, primary and secondary phyllosilicates, carbonates, and chlorides. This study provides insight into the limitations regarding the use of VNIR in characterizing complex mineral assemblages inherent in lacustrine settings.

Concept for a new frontiers mission to Ganymede: A Planetary Science Summer School study

As part of the NASA Planetary Science Summer School 2010, the Ganymede Interior, Surface and Magnetosphere Observer (GISMO) team developed a robotic mission to Ganymede, one of Jupiters icy moons. This process included the formulation of the science objectives and the selection of a payload tailored to meet these goals. The team then designed a mission architecture aimed toward achieving the science objectives. Using a sequence of 14 flybys of Ganymede, the vehicle would use a simple, staged operation of the science payload. This timeline allows for a simplified design, with relatively low risk and cost. Principle challenges included the finite power available to the vehicle, along with a limited data downlink rate. Otherwise, this preliminary design would meet all mission requirements, as determined by the science goals, and within the allocated cost cap.

Microbial Detection Array (MDA), a Novel Instrument for Unambiguous Detection of Microbial Metabolic Activity in Astrobiology Applications

MDA is designed as a test bed for an astrobiology field instrument to detect microbial metabolic activity in terrestrial or extraterrestrial geological soil samples. MDA employs electrochemical sensors in a unique differential chamber configuration, able to detect minute changes in the chemical composition between the two otherwise identical chambers. Both chambers are filled with identical autoclave-sterilized, sample-water mixtures. Only one of the chambers receives an additional minute, non-sterilized inoculation sample. Under the minimal assumptions that the geological sample contained nutrients (energy), organisms, and required water to initiate growth, the differential electrochemical measurements would now allow detection of metabolic activity, in addition to the electrochemical characterization of the soil samples in both chambers.