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Articles 1 - 5 of 5
Full-Text Articles in Physical Processes
An Investigation Into The Suitability Of Sulfate-Reducing Bacteria As Models For Martian Forward Contamination, Maxwell M. W. Silver
An Investigation Into The Suitability Of Sulfate-Reducing Bacteria As Models For Martian Forward Contamination, Maxwell M. W. Silver
Graduate Theses and Dissertations
The NASA Planetary Protection policy requires interplanetary space missions do not compromise the target body for a current or future scientific investigation and do not pose an unacceptable risk to Earth, including biologic materials. Robotic missions to Mars pose a risk to planetary protection in the forms of forward and reverse contamination. To reduce these risks, a firm understanding of microbial response to Mars conditions is required. Sulfate-reducing bacteria are prime candidates for potential forward contamination on Mars. Understanding the potential for forward-contamination of sulfate-reducers on Mars calls for the characterization of sulfate-reducers under Mars atmosphere, temperature, and sulfate-brines. This …
Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel
Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel
Dissertations and Theses
Asteroid bombardment contributed to extensive melting and resurfacing of ancient (> 3 Ga) Mars, thereby influencing the early evolution of the Martian crust. However, information about how impact melting has altered Mars’ crustal petrology is limited. Evidence from some of the largest impact structures on Earth, such as Sudbury and Manicouagan, suggests that some impact melt sheets experience chemical differentiation. If these processes occur on Mars, we expect to observe differentiated igneous materials in some exhumed rock samples. Some rocks observed in Gale crater are enriched in alkalis (up to 14 wt% Na2O + K2O) and …
Martian Cave Air-Movement Via Helmholtz Resonance, Kaj E. Williams, Timothy N. Titus, Chris H. Okubo, Glen E. Cushing
Martian Cave Air-Movement Via Helmholtz Resonance, Kaj E. Williams, Timothy N. Titus, Chris H. Okubo, Glen E. Cushing
International Journal of Speleology
Infrasonic resonance has previously been measured in terrestrial caves by other researchers, where Helmholtz resonance has been suggested as the plausible mechanism resulting in periodic wind reversals within cave entrances. We extend this reasoning to possible Martian caves, where we examine the characteristics of four atypical pit craters (APCs) on Tharsis, suggested as candidate cave entrance locations. The results show that, for several possible cave air movement periods, we are able to infer the approximate cave volumes. The utility of inferring cave volumes for planetary cave exploration is discussed.
Infrared Spectra Analysis Of Thermally Altered Iron Phyllosilicates And The Implications For Mars, William Thomas Bryan
Infrared Spectra Analysis Of Thermally Altered Iron Phyllosilicates And The Implications For Mars, William Thomas Bryan
Graduate Theses and Dissertations
This study looks at two iron-rich phyllosilicates, which may be present on Mars. The minerals, greenalite and hisingerite, are rich in iron-II and iron-III, respectively. Small samples (~0.40 grams) of each mineral were crushed and heated in a Lindberg Tube Oven for approximately twenty-four hours at temperatures selected to mimic lava flows and impact events. Following heating, each sample was placed in a Fourier Transform Infrared (FT-IR) spectrometer to collect the near- and mid-infrared spectra. The spectra allowed for these terrestrial analogs to be analyzed with regards to how their structure breaks down with increasing temperature. The samples' colors were …
Stability Of Phyllosilicates On Mars, Patricia Gavin
Stability Of Phyllosilicates On Mars, Patricia Gavin
Graduate Theses and Dissertations
This study investigates the stability of phyllosilicates on the surface of Mars through laboratory experiments and analysis of terrestrial analogs. Phyllosilicates are mostly found in the oldest Noachian terrains on Mars and hence hold clues to the planet's earliest aqueous and geologic history. Phyllosilicates relevant to Mars were heated up to ~1100°C for up to 24 hours and impacted with projectile velocities up to ~4.5 km/s. Heated samples were analyzed using x-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy in the near- (NIR, 1.0-2.5 µm) and mid-infrared (MIR, 5.0-15.0 µm) ranges. Impacted samples were also analyzed using Raman spectroscopy …