<p>Although decades of experience in human spaceflight have produced and refined a wealth of operational knowledge, the unique challenges posed to long-term extraterrestrial surface habitats will require new approaches to mission design. The key objectives of this thesis are to develop an understanding of 1) how to use simulation to study these habitats and 2) how to make contingency plans for these habitats under complex, changing conditions. In order to accurately represent the challenges posed, we identify the common qualities of mission architectures that are likely to be present in near-future habitats. These qualities are used to formulate sample crew schedules that contribute to developing realistic models for meaningful research. We discuss the development of such models and demonstrate the suitability of simulation to enable the design and study of resilient space habitats. Simulation can be used as a tool to understand the challenges and consequences associated with decision making, as well as the importance of resilient design choices in a hazard-prone environment. We then identify aspects of vulnerability in space habitat mission operations, the subfactors that influence changes in habitat vulnerability, and the effects of each identified category of vulnerability. These ‘vulnerability factors’ are subsystem availability, environmental conditions, safety control options, and recent events. Each vulnerability factor has several subfactors that influence its change during a mission.</p> <p><br></p> <p>The set of vulnerability factors is significant because each captures some category of behavior in surface habitats that changes over time and impacts the likelihood or consequences of risks to the habitat. We use these vulnerability factors to formulate six research questions which can be addressed via simulation-based research. A simulation set plan is developed to highlight the significant concepts at play in each research question. Finally, we conduct trials and analyses of these questions via simulation by injecting faults into a modular coupled virtual testbed for space habitats. The results of the simulations are used to develop lists of key implications for each vulnerability factor in practice. In addition, the lessons learned over the course of simulation set design and the usage of the simulation tool are discussed to support future simulation-based research efforts. We conclude by summarizing the major findings and potential for future work in the area.</p>

Hypothesised causes of the observed world-wide decline of amphibian populations are varied and in some cases contentious. Insufficient information relating to the autecology of many amphibian species can cause erroneous speculations regarding critical habitat requirements and hence management programs designed to enhance population viability are often unsuccessful. Most amphibians display a bi-phasic life history that involves occupation of an aquatic breeding habitat and terrestrial habitats that are used for foraging, and shelter from predation and environmental stress. However, the focus of most amphibian research is centred on the breeding habitat, with limited research being conducted into the terrestrial habitat requirements of most amphibian species. Barakula State Forest is a large continuous area of open woodland situated in the semi-arid region of Queensland. The forest supports 21 species of endemic anurans, many of which use ephemeral waterbodies for breeding. This area is, therefore, an ideal location to test the relative importance of terrestrial habitat on the distribution of a suite of frogs that display different morphological and physiological characteristics. On the landscape scale, the attributes of the terrestrial environment at three survey areas within Barakula were similar. However, at the patch scale, ground truthing showed there were considerable variations in vegetation and ground cover attributes within and between each survey site. Measured properties of the soil also tended to vary within and between sites. Soil texture ranged from sandy to heavy clay, soil pH ranged from 3.9 to 6.4 and soil moisture varied considerably. Agar models, used for testing evaporative moisture loss at different microhabitats, retained significantly higher levels of moisture when positioned in the buried microhabitat during summer, but in winter, models that were placed under leaf litter retained higher levels of moisture. Variations in levels of moisture loss at the five different microhabitats were evident within and between the survey sites. Despite a prolonged drought, 1844 native frogs representing 17 species were pitfall trapped. Members from the family Myobatrachidae comprised 94% of these captures, and burrowing species accounted for 75% of total captures. Species were not randomly distributed within or between the survey sites. Vegetation attributes and soil properties played a significant role in influencing the catch rates and traplines that supported similar vegetation and soil attributes also tended to catch similar species. Capture rates of six of the seven burrowing species were significantly influenced by soil properties. When given a choice of four different microhabitats created in enclosures, individuals from five species showed varying responses to habitat choice during night time activity. During daylight all species tended to avoid bare areas and burrowing species tended to burrow under some form of cover. Pseudophryne bibronii metamorphs showed a significant avoidance to soils with high pH. The number of Limnodynastes ornatus metamorphs was significantly and positively correlated with moisture levels surrounding a breeding area. Limnodynastes ornatus metamorphs tended to avoid areas that did not support some form of cover. Embryos from the terrestrial egg laying P. bibronii translocated to sites with varying levels of soil pH, suffered increased mortality where the soil pH was &gt4.8. In the laboratory, embryonic survival was not significantly different between the four pH treatments. There was a significant influence of fungal infection on survival rates and ranked fungal infection was significantly different between the four pH treatments. The terrestrial environment at the three survey sites has provided sufficient protection from environmental elements to allow a large diversity of anurans to persist for long periods without access to permanent water. Management must consider the importance of the non-breeding habitat when defining buffer zones, restoration programs and conservation strategies to ensure that the complete set of ecological requirements for frog species are provided.

<p>  </p> <p>In the wake of the first Artemis launch, humanity is more focused on space exploration and travel than it has been in the half a century since the Space Race. This time, it’s not enough just to touch down on the Moon; we want to build sustainable homes on the Moon and on Mars. The goal of long-term extra-terrestrial habitation begs the question: how do we design habitats that can protect human life so far from Earth?</p> <p><br></p> <p>The Resilient Extra-Terrestrial Habitat Institute (RETHi) has been operating for four years now building a foundation of ideologies and tools to help answer that question. The institute has developed a control-theoretic approach to habitat resilience based on a state-trigger analysis, a database of potential hazards to a habitat, metrics for resilience quantification, and simulation platforms for design verification.</p> <p><br></p> <p>The combination of these developments allows for the proposition of a resilience-oriented habitat design process. The process takes the shape of a typical systems vee and is tailored to the needs of an extra-terrestrial habitat and the tools available through RETHi. The process proposes a way to build resilience into the requirements development and design verification of extra-terrestrial habitats at three system levels. The result of this study is a discussion on how we design, evaluate, and select safety mechanisms for extra-terrestrial habitats.</p> <p><br></p> <p>Safety mechanisms are selected by simulating the habitat’s response to a disruption when equipped with one safety mechanism at a time and quantifying the habitat’s resilience. Then, the resilience of the habitats with different mechanisms are compared, illuminating the best option. Simulations for each mechanism are performed under a variety of circumstances, changing the time of day and intensity of the disruption as well as the type of repair agent carrying out the mechanism to capture the habitat’s behavior as totally as possible.</p> <p><br></p> <p>This analysis shows how different safety mechanisms performances compare and provides a basis for making design decisions.</p>