Browsing by Author "Andersen, Noah"

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Analysis on the Effect of Flow Interruption in the Oxygen Ventilation Loop on Inspired Carbon Dioxide
(51st International Conference on Environmental Systems, 7/10/2022) Andersen, Noah
The Oxygen Ventilation Loop (OVL) of the Exploration Portable Life Support Subsystem (xPLSS) provides oxygen gas (O2) and removes water (H-2O) and carbon dioxide (CO2) from the Exploration Extravehicular Mobility Unit (xEMU). The Rapid Cycle Amine (RCA) uses two cycling beds to remove CO2 and H2O from the OVL. Flow through the OVL is interrupted when the RCA switches between the two beds. This paper discusses an analysis conducted to determine the impact of the OVL flow interruption on the inspired partial pressure of CO2 (ppCO2). The analysis uses a computational fluid dynamics (CFD) model of the upper portion of the Exploration Pressure Garment Subsystem (xPGS) to determine the ppCO2 inspired by the crewmember during the flow interruption. The impact of various parameters on the inspiration of elevated ppCO2 by the crewmember is analyzed. This analysis shows that flow interruption in the OVL causes the first inhale after the interruption to have elevated ppCO2. However, the inspired ppCO2 returns to near nominal values by the second inhale, so the impact of flow interruption on the average ppCO2 is small. The effect of the flow interruption is most significant with high metabolic rates and long flow interruption times.
Comparison of Exploration Portable Life Support Subsystem (xPLSS) Thermal Modeling to Thermal Vacuum Testing
(2024 International Conference on Environmnetal Systems, 2024-07-21) Sladek, Chane; Andersen, Noah; Goodman, Emma; Lewandowski, Michael; Westheimer, David
To support NASA's goal to return to the Moon through the Artemis Mission, the development of an Exploration Portable Life Support Subsystem (xPLSS) has been conducted at Johnson Space Center (JSC). As part of this development process, a large system level thermal/fluid model of the xPLSS was developed using Thermal Desktop and an in-house human model (METMAN). The xPLSS model was used throughout the design process to predict the performance and temperature of nearly all components within the xPLSS. In the fall of 2023, the Design, Verification, and Testing (DVT) unit of the xPLSS was tested in a thermal vacuum (TVAC) chamber at JSC. This testing consisted of combining the xPLSS with an upper torso of the Exploration Pressure Garment System (xPGS) and simulating five Extravehicular Activities (EVAs) in extreme thermal conditions (two cold EVAs and three hot EVAs). The data generated in this test series provided system level data of the xPLSS operating in vacuum and at flight-like environmental temperatures for the first time. These data were compared to results output by the xPLSS system model to assess the accuracy of previous analyses and improve the fidelity and accuracy of the xPLSS system model. The comparison between model and test hardware provides valuable insight that will help improve the design and fidelity of next generation space suits.
Extravehicular Mobility Unit System-Level Model (SINDA EMU) Usage for Operational Mitigations in Support of US EVA 80
(2023 International Conference on Environmental Systems, 2023-07-16) Andersen, Noah; Miranda, Bruno
During United States Extravehicular Activity 80 (US EVA 80), water was observed in the helmet of an Extravehicular Mobility Unit (EMU) during cabin repressurization. Through a comparative analysis and Test, Teardown, and Evaluation (TT&E) of this EMU, the most likely cause of the US EVA 80 water failure was determined to be sublimator carryover caused by a comparatively high latent load (water vapor production by the crewmember). High latent load can be reduced by the crewmember adjusting the thermal control valve (TCV) setting on the EMU to prevent the onset of significant sweating. To reduce the risk of high latent load leading to water in the helmet, a potential warning system was developed using the Systems Improved Numerical Differencing Analyzer EMU model (SINDA EMU). The goal of this warning system is to alert the crewmember when they are producing a high latent load and recommend adjustment of the TCV to increase cooling. This warning system was designed to ensure high risk conditions are avoided while simultaneously preventing a system that warns the crewmember too frequently. Theoretical tests of the warning system through modeling calculated that if the warning system were used during US EVA 80, the total latent load could have been reduced by up to 33% which would have significantly reduced the risk of water in the helmet. This analysis also investigated the effectiveness of the warning system on EVAs that occurred after US EVA 80.
In-Situ Resource Utilization Modeling of a Lunar Water Processing System
(2024 International Conference on Environmnetal Systems, 2024-07-21) Carlson, Avery; Andersen, Noah; Collins, Jacob
A key element of achieving a sustained surface presence, such as defined in NASA's Artemis plan, is In-Situ Resource Utilization (ISRU). ISRU is the practice of using local resources to provide mission consumables that reduce system launch mass requirements, and regenerate resources (chiefly, water and oxygen) for propulsion and life support supporting both Lunar and Martian missions. ISRU systems require multiple complex processes, such as excavation, chemical reactors, and electrolysis subsystems that must operate in harmony to optimize the overall system process from beginning to end. The Mission Analysis and Integration Tool (MAIT) was previously developed with MATLAB in FY22 to connect individual subsystem models into a customized, flexible framework for the purpose of technology downselect, optimization, and end-to-end process planning. Beginning in FY24, MAIT became the capital program in the Systems Engineering and Integration (SE&I) ISRU Modeling and Analysis (SIMA) project. MATLAB/Simulink was leveraged due to its ability to communicate with other programming languages. MAIT initially evaluated a suite of ISRU-related technologies, including the water processing Lunar Auger Dryer for ISRU (LADI) system with integrated upstream excavation and downstream electrolysis subsystems. With individual models consolidated, the MAIT tool generated over 5,000 cases during its first round of parametric sweeps on the water processing architecture at multiple production targets; the system analysis provided the optimal LADI geometry that minimized energy demands, estimated effects to cold trap size and radiator requirements, and calculated the power dynamics of the electrolysis unit and liquid oxygen storage volume. Additional efforts are being made to demonstrate the ability to scale ISRU technologies supporting the Space Technology Mission Directorate's (STMD) commercialization strategy and increase the MAIT software capability. Work is ongoing for a wide array of ISRU system models beyond the Lunar environment, e.g. production of propellant for a Martian lander.