Browsing by Author "Fester, Zachary"
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Item Exploration Extravehicular Mobility Unit (xEMU) Lunar Boot Chamber B Thermal Vacuum Testing Results(2024 International Conference on Environmnetal Systems, 2024-07-21) Swartout, Ben; Fester, Zachary; Westheimer, DavidNASA�s Exploration Extravehicular Mobility Unit (xEMU) is the government reference next-generation space suit design and is engineered to protect astronauts from extreme lunar environmental temperatures. To evaluate the xEMU hardware thermal requirements, the xEMU Testing Team invented, designed, and executed a dual-suit, uncrewed thermal vacuum (TVAC) test at Johnson Space Center�s (JSC) Chamber B. This paper details the test methodology, hardware setup, and results from the xEMU lunar boots. Eleven unique thermal profiles were tested, including both cold and hot environmental cases, over the course of five continuous days of testing. The radiative thermal environment was controlled through exposure to liquid-nitrogen shrouds on the chamber walls and through a heater cage surrounding the boots. Notably, the xEMU boots also contacted the liquid-nitrogen chilled floor inside of Chamber B, which provided a conduction pathway to simulate the thermal effects of the lunar surface. Test hardware was developed to extend the water tubing from the Liquid Cooling Ventilation Garment (LCVG) into the boots to set the internal thermal boundary nominally provided by the astronaut�s foot. Thirty-three temperature sensors were used to collect data in critical locations in the xEMU boot assembly, as well as for calorimetry to determine heat flux to and from the boots. This paper will document the testing results and compare the test data against the xEMU boot and system-level thermal models for model validation. To conclude, this paper will address knowledge gaps presented by unmanned thermal vacuum testing with regard to the boots and the current state of lunar boot thermal testing.Item NASA Advanced Space Suit xEMU Development Report -- Lunar Boots(51st International Conference on Environmental Systems, 7/10/2022) Mcfarland, Shane; Fester, ZacharyFor the past several years, the Exploration Extra-Vehicular Mobility Unit (xEMU) team at NASA's Johnson Space Center has focused on the development and detailed design of the xEMU to support missions to the International Space Station (ISS) and a moon landing in 2024. In that context, this paper examines the development and baseline detailed design of the Lunar Boots. This paper will outline the challenging technical requirements, significant architectural trades, technical solutions required to overcome these challenges, and a current status of the detailed design. The preliminary results of Design Verification Testing (DVT) as it relates specifically to this hardware will also be provided, along with a forward strategy for final maturation into a flight-ready design.Item Testing the Exploration Conops(Excon) Mockup Suit in Lunar Analog Environments in 2022(2023 International Conference on Environmental Systems, 2023-07-16) Tejral, Zachary; Flaspohler, Christine; Keomany, Tommy; Graff, Trevor; Fester, Zachary; Davis, Kristine; Coan, DaveUnderstanding how to effectively train for Extravehicular Activities (EVAs) for Artemis missions is critical. Developing high-fidelity simulation environments is important for Artemis mission preparation. Because the actual Lunar exploration environment cannot be fully replicated on Earth, it is paramount to determine where and how to properly train the Artemis team. The overall focus for this test series was developing the capability to perform Artemis simulated EVAs in high-fidelity, full-scale environments. This test series was broken into 3 distinct tests titled after the EHP integrated test team: Joint EVA Test Team (JETT). The test locations are planned to serve as Artemis training sites and were selected because of their relevance to the expected Artemis Lunar terrain. JETT1 was conducted near Kilbourne Hole by El Paso, Texas and focused on hardware development and checkout. JETT2 was conducted in the Icelandic Highlands and began the transition towards EVA concept operations (con-ops), risks and technology. JETT3 was conducted near SP Crater by Flagstaff Arizona and focused on simulating the Artemis III mission with a simulated Houston based Flight Control Team (FCT) and a Science Mission Directorate (SMD) science team. All three JETT tests utilized the Excon mockup space suit. The Excon mockup suit is a light-weight, unpressurized Exploration Extravehicular Mobility Unit (xEMU) simulator. While it cannot replicate the feel of working within a pressurized suit, it does introduce similar volume constraints and some of the mobility programing to simulate the user experience in the xEMU. Overall, the JETT testing was able to create a simulated Lunar EVA and have two subjects perform full scale operations in line with Artemis III mission expectations. Future work is planned to continue to improve the simulation quality of Lunar EVA simulations.