Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 191-205).

La recherche de molécules organiques à la surface de Mars est l’un des enjeux majeurs pour caractériser son habitabilité passée et/ou présente. C’est l’un des objectifs de la mission spatiale Mars Science Laboratory (MSL) et en particulier de l’instrument Sample Analysis at Mars (SAM) à bord du robot Curiosity. Cette thèse s’inscrit dans l’aide au traitement et l’interprétation des données de SAM, en vue de détecter et d’effectuer l’inventaire des molécules organiques à la surface de Mars. Ces travaux portent en premier lieu sur les performances analytiques du chromatographe en phase gazeuse (CPG) de SAM et sur l’identification des molécules organiques dans les échantillons solides martiens analysés. A cette fin, j’ai étudié les performances de la chaine d’injection et de séparation du CPG de SAM dans les conditions opératoires de vol reproduites en laboratoire. J’ai également créé une base de données des temps de rétention de molécules présentes, et potentiellement présentes sur Mars, qui sert de référence pour le traitement des données de vol. Ces données ont permis d’identifier des molécules organiques dans les échantillons solides martiens et d’expliquer pourquoi certaines d’entre elles, supposées présentes, ne sont pas détectées. La deuxième partie de l’étude est focalisée sur l’impact des minéraux oxychlorés sur les molécules organiques, lors de la pyrolyse. Pour ce faire, j’ai développé une approche systématique d’étude de la pyrolyse de molécules organiques en présence de minéraux oxydants, ayant tous deux une forte probabilité de se trouver à la surface de Mars. J’ai ainsi pu étudier l’évolution et/ou destruction des molécules organiques, déterminer celles pouvant être à l’origine des composés chlorés détectés sur Mars, évaluer l’impact de la concentration en minéraux oxychlorés et celui du paramètre de température de pyrolyse. Les résultats indiquent que le nombre, la nature, et les abondances relatives des composés formés au cours de la pyrolyse, dépendent de la nature des phases minérales et organiques, de la concentration en minéraux oxychlorés et de la température de pyrolyse. / The search for organic molecules at the Mars’ surface is of primary interest to understand its past and/or present habitability. It is one among the main goals of the Mars Science Laboratory (MSL) space mission and especially of the Sample Analysis at Mars (SAM) experiment onboard the Curiosity rover. This thesis deals with the support to the SAM data treatment and interpretation, which aims to detect and inventory the organic molecules at the Mars’ surface. The first part of this work focuses on the analytical capabilities of the SAM gas chromatograph (GC) and the identification of the organics in the solid samples analysed on Mars with the flight model. To do so, I studied the analytical chain from injection to separation of the SAM GC in the flight operating conditions reproduced in the laboratory. I also created a library of retention times for molecules present or potentially present on Mars, and used as a reference library to treat the flight data. These data allowed to identify the organics in the martian solid samples, and to explain why a few molecules, expected to be present, are not detected. The second part of the thesis focuses on the impact of oxychlorine phases on the organics, during the pyrolysis process. With this aim, I developed a systematic approach to study the pyrolysis of organic molecules on the presence of oxidant minerals that have a high probability of presence at the Mars surface.The evolution and/or destruction of the organics was evaluated. We also looked for the organic and inorganic compounds that can be the precursors of the chlorohydrocarbons detected on Mars with SAM. Finally, we evaluated the influence of the oxychlorines concentration and of the pyrolysis temperature parameter. The results show that the number, the nature and the relative abundances of the compounds formed during the pyrolysis, depend on the nature of the organic and inorganic phases, of the concentration of the oxychlorines phases and of the pyrolysis temperature.

Approved for public release, distribution is unlimited / Nuclear power is the next enabling technology in manned exploration of the solar system. Scientists and engineers continue to design multi-megawatt power systems, yet no power system in the 100 kilowatt, electric, range has been built and flown. Technology demonstrations and studies leave a myriad of systems from which decision makers can choose to build the first manned space nuclear power system. While many subsystem engineers plan in parallel, an accurate specific mass value becomes an important design specification, which is still uncertain. This thesis goes through the design features of the manned Mars mission, its power system requirements, their design attributes as well as their design faults. Specific mass is calculated statistically as well as empirically for 1-15MWe systems. Conclusions are presented on each subsystem as well as recommendations for decision makers on where development needs to begin today in order for the mission to launch in the future. / Lieutenant, United States Navy

Mars is the fourth planet from the Sun and its interaction with the solar wind is a quite interesting subject tostudy. While it is a rocky planet it doesn't have an intrinsic magnetic eld, but an ionosphere, created by thephotoionization of a relatively thin atmosphere. In addition there are magnetic "patches" on its surface, remnantsof an ancient fossilized magnetic eld. All these factors make the study of its interaction with the solar wind quiteintriguing. In this work we tried to extract information about the electron population and the magnetic eld intensity aroundthe planet, but also about the corresponding pressures to those magnitudes: electron -thermal- and magneticpressure respectively. Also, we tried to determine the position of the magnetic pileup boundary (MPB) andcompare it to the theoretical one, and lastly, we search for any possible structures along the MPB -both aboveand below it- by analyzing the ratio of the above mentioned pressures.We used data collected by Mars AdvancedRadar for Subsurface andIonosphereSounding (MARSIS), in a period of almost 9 years - December 2005 to May2014.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / In response to the need to analyze and report upon Electronic Warfare (EW) test data results in a comprehensive and uniform manner, the Mission Analysis and Reporting System (MARS) has been developed. MARS is a government owned PC based Windows application designed for rapid analysis and reporting upon EW test mission data. MARS currently performs Jammer Effectiveness ( Reduction In Lethality, Increase In Survivability, Reduction In Shot, and Reduction In Hit), Radar Warning Receiver (RWR) System performance (Threat ID, Response Time/Ageout, and Direction Finding (DF) Accuracy), and Tracking Error Statistics. Additionally, MARS produces several graphical outputs including polar plotting, dynamic strip charting, Cumulative Distribution Functions (CDF), and RWR Simulated Scope. Continual development and maintenance of MARS at the Air Force Development Test Center, Eglin Air Force Base, Florida, has provided a proven product used by numerous DT&E and OT&E test projects over the last four years.

This thesis reports on algorithmic design and software development completed for the Medipix All Resolution System (MARS) multi-energy CT scanner. Two areas of research are presented - the speed and usability improvements made to the post-reconstruction material decomposition software; and the development of two algorithms designed for the implementation of a novel voxel system into the MARS image reconstruction chain. The MARS MD software package is the primary material analysis tool used by members of the MARS group. The photon-processing ability of the MARS scanner is what makes material decomposition possible. MARS MD loads reconstructed images created after a scan and creates a new set of images, one for every individual material within the object. The software is capable of discriminating at least six different materials, plus air, within the object. A significant speed improvement to this program was attained by moving the code base from GNU Octave to MATLAB and applying well known optimisation routines, while the creation of a graphical user interface made the software more accessible and easy to use. The changes made to MARS MD represented a significant contribution to the productivity of the entire MARS group. A drawback of the MARS image reconstruction chain is the time required to generate images of a scanned object. Compared to commercially available CT systems, the MARS system takes several orders of magnitude longer to do essentially the same job. With up to eight energy bins worth of data to consider during reconstruction, compared to a single energy bin in most com- mercial scanners, it is not surprising that there is a shortfall. A major performance limitation of the reconstruction process lies in the calculation of the small distances travelled by every detected photon within individual portions of the reconstruction volume. This thesis investigates a novel volume geometry that was developed by Prof. Phil Butler and Dr. Peter Renaud, and is designed to partially mitigate this time constraint. By treating the volume as a cylinder instead of a traditional cubic structure, the number of individual path length calculations can be drastically reduced. Two sets of algorithms are prototyped, coded in MATLAB, C++ and CUDA, and finally compared in terms of speed and visual accuracy.

This work describes the design, development and testing of a portable charge-coupled device detector system to be used for the simultaneous collection of X-ray diffraction and X-ray fluorescence data from powdered samples. The detector was designed for both terrestrial and extra-terrestrial applications that require in-situ analysis of samples, where access to a laboratory instrument is restricted. The detector system incorporates 4 e2v technologies CCD30-11 devices, employing multi-phase pinned technology for low noise operation. Geometrical calculations and thermal studies concerning the design of the detector are presented, with particular emphasis on motivations for the chosen geometry. Initial characterisation and calibration of the detector was performed in a laboratory environment using a purpose built test facility. The test facility included a high brightness X-ray micro-source from Bede Scientific Instruments, coupled with an XOS polycapillary collimating optic, which was used to deliver a focused beam of low divergent X-rays to the sample. The design of the test facility is discussed and the spectra and flux produced by the X-ray micro-source are investigated. The operational performance of the detector is highlighted and the use of the instrument in different applications is described, namely the planetary sciences and pharmaceuticals sector. Finally, based on the knowledge gained from initial testing of the instrument, improvements to the detector design are outlined, which greatly enhance the combined X-ray diffraction/X-ray fluorescence performance of the instrument.

The research is concerned with investigating the storage and usage of liquid Hydrogen and Oxygen over a long duration. For this purpose a mission was defined where these two propellants are used to transport a six man crew to Mars and back. The mission duration is a total of 972 days in length with a stopover time at Mars of 454 days. A baseline spacecraft is designed. The two driving philosophies behind the design are reliability and reusability. This baseline spacecraft design was used a a basis for analysing the extreme thermal environment and its impact on the propellant storage temperatures. Also it allowed the calculation of mass and propellant budgets. It was found that the Hydrogen fuel undergoes a change of phase when the vehicle is orbiting Mars. Hence a escape manoeuvre trajectory simulation was performed which analysed the escape trajectory, acceleration and duration, and assessed the impact on the initial Earth launch propellant budget. I addition, a number of trade-offs were performed in order to increase the efficiency of the propulsion system from its nominal design in which the Hydrogen gas is allowed to expand directly from the storage tanks through the engine. The optimum arrangement that was found was to bleed the gas into a small high pressure tank and allow the fuel to be heated by waste heat from the onboard nuclear reactor. The results indicated that not only does this provide a performance increase over the nominal system but also the amount of propellant required for this bum is smaller than the storable options considered in the literature. Hence this analysis demonstrates that Hydrogen and Oxygen can be stored and used over long periods, and that they can still provide a better propellant performance than storable options, even with the increased mass penalty associated with using them on a mission such a this one.

It is clear that a planet's ability to support life is intimately associated with its physical evolution, but many aspects of this link have not been resolved. For example, differing geologic histories have the potential to drive large-scale differences in the chemistry of planets’ waters, with unknown implications for habitability. In this thesis, I link the geochemical evolution of Mars to the habitability of its associated evaporitic or brine environments, which have been widespread throughout the planet's history. Their habitability is compared with the Earth system, where a chloride-dominated chemistry permits the microbial colonisation of brines with extremely low water availability. By assessing the physicochemical environments in martian brines, I present evidence that high ionic strength, driven to extremes on Mars by the ubiquitous occurrence of divalent ions, can influence habitability even if water availability is high. The importance of this parameter has been overlooked in terrestrial microbiology, likely due to the paucity of environments with high levels of di- or multivalent ions, and its possible mechanics and significance for defining habitat space on Earth and other planets are discussed. Additionally, cultivation techniques and next-generation DNA sequencing were used to identify organisms capable of growth in extreme Mars-relevant brines, which contrast with those typically found in NaCl-rich brines on the Earth. The isolation of a novel sulfate-tolerant Marinococcus strain, and its growth response to fluctuating martian brine compositions are reported. These results show that microbial growth kinetics are defined not merely by additive ion effects, but rather by bulk physicochemical conditions defined by complete ion assemblages. Changes to composition driven by evaporation or freezing can therefore push a brine into more biologically clement conditions by altering a brine’s physicochemical profile The data herein present a strong case that geochemical context is essential to understanding habitability in extreme saline environments. A new framework for predicting brine habitability is required, taking into account the geochemical history of the brine as well as the effects different ionic compositions exert on microorganisms. This work is a significant contribution across several fields, and emphasises the value of interdisciplinary science in answering questions of planetary habitability. Furthermore, this thesis provides a case study for exploring the impact of planetary-scale geochemical evolution on the ability of a planet to support life.

Basalts from Askja, Iceland have high MgO (5-18 wt %) and high Fe2O3 (5-18 wt %: Baratoux et al., 2011; Mangold et al., 2013, this study) similar to Martian basalts, which have Fe2O3 from 10-33 wt % McSween et al, 2006; Ming et al., 2008]) and MgO around 11 wt. % (McSween et al., 2009). Askja’s cold desert climate provides a good weathering analogueanalog (Mountney and Russell, 2004). Askja is located in the Northern Volcanic Zone of Iceland and basalts have been weathered to form mafic volcaniclastic deposits in a 40-km long sand sheet to the E-SE of the Askja caldera complex (Fig. 1; (Kuritani et al., 2011). The 2014-2015 Holuhraun eruption was emplaced onto the southeastern part of the sand sheet (Fig. 1) and altered the regional geomorphology and may have impacted the geochemistry of the sand sheet itself by addition of wind-blown ash and crystals, plus weathering of the lava flow (MgO content of ~7.1 wt % Geiger et al., 2016). Mangold et al. (2011) found that Icelandic sands show little chemical variations but that study was limited in the number of samples (12 sand samples and 12 rock seven rock, seven sand; Mangold et al., 2011). Here we expand on that study and we have created a morphological and geochemical database with the goal of identifying relevant trends to past and present Martian environments. The Askja sand sheet, between ~10 cm and ~10 m thick, covers 240 km2 (Mountney and Russell). Mountney and Russell described three distinct sections of the sand sheet. The southwest section is deflationary and defined by very fine to medium grained basaltic sand with cobbles and boulders of lithologies sourced from adjacent to and distal from the sand sheet. The central part is inflating and is dominated by very fine-grained sand, relict lava fields, and small to large sand ripples. The northeast portion is also inflating but that accumulation is limited to topographic depressions. The northeast, characterized by sand mostly composed of pumice from the 1875 Askja eruption and basalt clasts from local lava fields, was not studied in detail here due to the difference in chemistry. Martian basaltic eolian sediments may record a long history of local and global climate change and they may have been potential habitats where water, nutrients and organic carbon mixed below the surface (Blake et al., 2013; Fisk et al., 2013). Basaltic sand fields on Earth have not been characterized as well as felsic sands, but represent a unique analog to deposits such as the Stimson Fm. on Mars (Mangold et al., 2011; Banham et al., 2016; Gupta et al., 2016; Ming et al., 2016; Newsom et al., 2016; Yen et al., 2016) . Eolian dominated weathering prevalent at Askja volcano, Iceland, likely also occurred on Mars and Askja mafic volcaniclastic dunes could be the best morphological and compositional analogueanalog for Martian eolian dunes (Edgett and Lancaster, 1993).