Magmatic Intrusions into the Sulfur-Rich Carmel Formation on the Colorado Plateau, USA: Implications for the Mars 2020 Mission

We report on basaltic dikes in the Colorado Plateau, which crosscut sulfate bearing sediments and compare this to Martian basalts and basaltic sediments in contact with sulfate mineralizations

Alteration and Oxidiation of an Olivine Lamprophyre Dike from Southern Utah, USA: An Analog for Mars

We report on oxidized basaltic dike intrusions on the Colorado Plateau as analog for Martian basalt oxidation

Radiation measurements in a simulated non-terrestrial atmosphere

A high-speed wind tunnel has been used to experimentally simulate the flow experienced by a capsule entering a planetary atmosphere. High speed photography showed that a steady test time of approximately 50 μs existed in the facility. Holographic interferometry has been performed to measure the twodimensional density distribution around a cylinder in the flow. A peak density ratio (density normalised by the free-stream density) of about 14 was observed. Emission spectroscopy allowed the characterisation of the conditions along the stagnation streamline in front of the capsule model. The results showed a temperature that varied between 8,500 K and 11,000 K in this region

Super-orbital re-entry in Australia - laboratory measurement, simulation and flight observation

There are large uncertainties in the aerothermodynamic modelling of super-orbital re-entry which impact the design of spacecraft thermal protection systems (TPS). Aspects of the thermal environment of super-orbital re-entry flows can be simulated in the laboratory using arc- and plasma jet facilities and these devices are regularly used for TPS certification work [5]. Another laboratory device which is capable of simulating certain critical features of both the aero and thermal environment of super-orbital re-entry is the expansion tube, and three such facilities have been operating at the University of Queensland in recent years[10]. Despite some success, wind tunnel tests do not achieve full simulation, however, a virtually complete physical simulation of particular re-entry conditions can be obtained from dedicated flight testing, and the Apollo era FIRE II flight experiment [2] is the premier example which still forms an important benchmark for modern simulations. Dedicated super-orbital flight testing is generally considered too expensive today, and there is a reluctance to incorporate substantial instrumentation for aerothermal diagnostics into existing missions since it may compromise primary mission objectives. An alternative approach to on-board flight measurements, with demonstrated success particularly in the ‘Stardust’ sample return mission, is remote observation of spectral emissions from the capsule and shock layer [8]. JAXA’s ‘Hayabusa’ sample return capsule provides a recent super-orbital reentry example through which we illustrate contributions in three areas: (1) physical simulation of super-orbital re-entry conditions in the laboratory; (2) computational simulation of such flows; and (3) remote acquisition of optical emissions from a super-orbital re entry event

Doctor of Philosophy

dissertationDiagenetic variables (e.g., microbial influence, sediment composition and fluid chemistry) are investigated to determine the effects on iron redox reactions and iron (oxyhydr)oxide nucleation, cement textures, mineralogy and chemistry. Three individual examinations are conducted in the Colorado Plateau, USA: 1. reservoir fluid chemistry in a natural fossil CO2 reservoir in the Jurassic Navajo Sandstone exposed in Justensen Flats in the northern San Rafael Swell, 2. concretion formation in the reactive, volcaniclastic Jurassic Brushy Basin Member of the Morrison Formation, and 3. comparative microbial influences in the precipitation of iron (oxyhydroxides) in a modern Ten Mile Graben spring system and the Brushy Basin Member. Bulk geochemistry in a lithologically controlled, iron (oxyhydr)oxide reaction front in Justensen Flats shows that the precipitating fluid in the reservoir was likely a CO2- and hydrocarbon-charged fluid and that CO2 injection into a saline reservoir would result in dolomite precipitation and significantly reduce porosity. Chemical and physical concretion comparisons in the Brushy Basin Member show that reactants are moving via fluid flow in porous host rocks and producing uniform concretion morphologies and mineralogies. In reactive Brushy Basin Member claystone and siltstone lithofacies, reactants are being sourced from abundant ashes reacting with groundwater to create localized diagenetic microenvironments and produce variable concretion mineralogies and morphologies. Variability of fluids on regional to outcrop scales and lithologically controlled fluid flow and cement precipitation in permeable reservoirs furthers the science of carbon capture and sequestration. Comparison of modern and 100ka microbial iron (oxyhydr)oxides in tufas at the Ten Mile Graben spring system shows that biosignatures exhibit some degradation and recrystallization on millennial time scales, although biotic features are clearly recognizable. Microbial fossils in the Brushy Basin Member are associated with macroscopic biotic features such as charophyte molds. Biogenic iron (oxyhydr)oxides in modern tufas and Jurassic rocks exhibit two distinct elemental suites that function as biosignatures: 1. C, Fe, and As, and 2. C, S, Se. Biogeochemical markers provide diagnostics for depositional environment, fluid chemistry and potential microbial fossils and/or biosignatures to aid in the exploration of similar iron- and clay-rich sediments on Mars in Gale Crater

Simulation of CO2–N2 expansion tunnel flow for the study of radiating bluntbody shock layers

A 25MJ/kg CO2–N2 expansion tunnel condition has been developed for the X2 impulse facility at the University of Queensland. A hybrid Lagrangian and Navier–Stokes computational simulation technique is found to give good correlation with experimentally measured shock speeds and pressure traces. The use of an inertial diaphragm model for describing secondary diaphragm rupture is found to estimate between 4% and 25% more CO2 recombination over the test time than the widely accepted holding-time model. The obtained freestream conditions are assessed for application to proposed bluntbody spectroscopy and subscale aeroshell experiments. The chemically and vibrationally excited freestream test gas is found to prevent exact thermochemical similarity from being achieved, and the strong radiation–flowfield coupling characteristic of Mars aerocapture conditions cannot be reproduced experimentally

Mission to the Trojan Asteroids: lessons learned during a JPL Planetary Science Summer School mission design exercise

The 2013 Planetary Science Decadal Survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar System. We present a conceptual design for a mission to the Jovian Trojan asteroids: the Trojan ASteroid Tour, Exploration, and Rendezvous (TASTER) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary Science Summer School. Our proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000 - 100 km over a 12 month nominal science data capture period. Our proposed instrument payload - wide- and narrow-angle cameras, a visual and infrared mapping spectrometer, and a neutron/gamma ray spectrometer - would provide unprecedented high-resolution, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar System. Although our mission design was completed as part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large differences in the complex trade-offs required when designing a mission to the Trojan asteroids.Comment: 38 pages, 8 tables, 4 figures. Accepted for publication in Planetary and Space Scienc

Magmatic intrusions into sulfur-rich sediments on the Colorado Plateau: an analog for Mars exploration

Mafic magmatism is a prevalent geologic process on Earth, and is a principal source of subsurface geologic change and energy influx on postNoachian Mars. While rare on Earth, the intrusion of mafic magmas into sulfur-rich soils and rocks is expected on Mars due to the observation of widespread high sulfur concentrations in Martian soils. On Mars, soils have been found to be rich in sulfur. Respectively, soil samples from Gusev Crater and Gale Crater contain between 4-8 weight percent, and 4-7 weight percent SO3, though ammounts[sic] as high as 31 weight percent have been measured in Gusev crater. With widespread sulfur-rich sediments and evidence of magmatism both ancient and young, mafic intrusions into rocks and sediments bearing significant quantities of sulfur species is expected on Mars. Processes associated with the magmatic intrusion of a sulfur-rich host, including degassing and alteration, may provide the requisite energy and nutrients for biological activity.On Earth, well exposed mafic dikes intrude the sulfur-rich sedimentary formations of the Jurassic San Rafael Group. Approximately 200 dikes, sills, and breccias can be found in proximity to the San Rafael Swell in Utah, and represent an Earth analog for a scenario of mafic magma intruding sulfur-rich sediments. Here we will investigate such an analog; a mafic dike intruding the sulfur-rich Jurassic Carmel Formation of the San Rafael Group