<p dir="ltr">To establish a long-term human presence on the Moon, it is necessary to have habitat systems that function effectively under challenging conditions and have sufficient autonomous technologies for fault detection and intervention. However, evaluating these habitats presents challenges due to their pervasive interdependencies and the harsh environmental conditions they must withstand. Thus, innovative testing techniques are vital to understanding and capturing the complexities these systems will encounter. </p><p dir="ltr">Thermomechanical real-time hybrid simulation (RTHS) provides unique opportunities to observe realistic behaviors and interdependencies, train models, test ideas, and validate methods. It is a cost-effective and accessible cyber-physical testing method that allows for the simultaneous experimental and computational modeling of systems, offering a comprehensive observation of their behavior under extreme dynamic conditions. This dissertation presents the development and experimental validation of a novel thermomechanical RTHS method to assess the multi-physics response of lunar habitat systems due to disruptive events. It outlines the conceptual framework, modeling approaches, and experimental considerations crucial to establishing the two-way coupling between a numerical and a physical subsystem through an innovative thermal transfer system. </p><p dir="ltr">The thermal transfer system utilizes a thermal actuator to impose distributed thermal loads on the experimental subsystem. The thermal actuator is identified considering switching-mode continuous dynamics for cooling and heating conditions. A switching control system is then developed to experimentally enforce the desired thermal conditions across different thermal cycles with minimum tracking error, adjusting the gains of the controller in response to varying temperature conditions. Furthermore, this dissertation demonstrates how to establish control and performance requirements for RTHS methods to effectively evaluate the realization of interface boundary conditions and determine acceptance criteria to perform RTHS tests with high confidence. </p><p dir="ltr">The RTHS method is experimentally implemented and validated through a series of scenario tests that simulate the cascading thermomechanical effects on a lunar habitat after a micrometeorite impact that damages its structural protective layer. These realistic tests aim to evaluate fault detection and decision-making methods in response to such disruptive events. Thus, using switching dynamic modeling, the RTHS problem formulation is designed to have numerical damage and repair capabilities, allowing interaction with these fault detection and intervention methods. The scenario results obtained through thermomechanical RTHS reveal behaviors and interactions that are not captured through purely numerical simulation or traditional experimental approaches. Through the experimental implementation of these scenario case studies, the thermomechanical RTHS method developed is the first of its kind to experimentally execute the effects of damage and repair intervention strategies in real-time on a numerical subsystem while simultaneously imposing the cascading effects on a physical specimen. </p><p dir="ltr">The findings of this dissertation advance our knowledge and offer insights into developing cost-effective and accessible cyber-physical methods to test novel ideas and technologies, thereby empowering and supporting space resilience and autonomy research. </p>

<p> </p> <p>There are several challenges that occur when creating extraterrestrial structures that are not relevant to terrestrial applications. The Resilient Extra-Terrestrial Habitat Institute is a NASA funded research project focused on developing resilient lunar habitats. In order to develop these deep-space structures, many considerations have to be made to account for scenarios that are not relevant to Earth. Such scenarios include meteorite impacts, moonquakes, radiation, and moon dust accumulation. To observe possible consequences of these disruptions, RETHi established a modular coupled virtual testbed to monitor the effects of different deep-space related situations. MCVT is a computer model of a lunar habitat that uses a system-of-systems approach to examine the impacts of these scenarios. Currently, MCVT is developing methods to confront these extraterrestrial situations by utilizing robotic agents and expanding upon a variety of safety responses to increase resiliency.  RETHi also utilizes a cyber physical testbed to run cyber-physical experiments to validate the approaches used in MCVT. </p> <p><br></p> <p>One of the numerous models in MCVT is the Habitat Interior Environment Model. HIEM monitors the interior environment of the lunar structure using physics-based calculations and inputs from its surroundings. There are three main disturbances that directly affect the interior environment—fire within the dome, meteorite impacts, and airlock failure. Such scenarios either increase or decrease the temperature and pressure. This data is then forwarded to other subsystems for further evaluation. HIEM can be remodeled to fit the pressure box in the cyber physical testbed. By doing so, it is then possible to validate the pressure leakage calculations used in HIEM using experimental data. HIEM is specifically designed to the lunar habitat currently in development; however, the model can be refitted to a variety of applications such as terrestrial, aerospace, space, and marine. </p>