Browsing by Author "Sepka, Steve"
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Item Design of a Jettison System For Space Transit Vehicles(51st International Conference on Environmental Systems, 7/10/2022) Sepka, Steve; Ewert, Michael; Lee, Jeff; Chen, Thomas; Venigalla, ChandrakanthMany options to re-use waste are currently being developed by NASA. These include combustion, compaction, torrefaction, and converting waste materials to an easily stored base polymer for future use. Human exploration missions require large amounts of supplies such as food, clothing and spare parts. A many-month journey to Mars will still result in the generation of a substantial amount of problematic waste products. It is thought that this waste must be discarded to enable a Mars transit mission. The most cost-effective, reliable, and safest method to address this problem may be to simply jettison these materials from the spacecraft. The ability to jettison requires a multi-component integrated system design. Major components include a launcher, airlocks, trash bags, and tracking system. Depending upon mission requirements, a jettison dedicated airlock may be necessary. In other cases, the crew airlock might be all that is needed. This paper will discuss these design issues and give guidance to a pathway forward.Item Reduction of Equivalent System Mass of a Trash Compaction Processing System with an Emphasis on Improved Thermal Efficiency(2024 International Conference on Environmnetal Systems, 2024-07-21) Pace, Gregory; Sepka, Steve; Richardson, Tra-My Justine; Martin, Kevin; Young, Janine; Trieu, SerenaA spacecraft life support system has been under development at NASA called the Trash Compaction Processing System that manages trash generated on human spaceflight missions. The trash composite typically includes components such as plastic pouches that contain wet food and drinks, used cotton clothing such as underwear and T-shirts, exercise clothing, used washcloths, expended deodorant containers, adhesive tapes, plastic bubble wrap, and other sundry items. The system uses compaction in combination with heat to turn the waste composite into a sturdy and well-defined shape, typically called a tile, which maintains structural integrity and makes the most efficient use of storage space. In addition to reducing the volume of the trash, the Trash Compaction Processing System removes water from the trash. The heating and removal of water from the trash renders it safe against microbial activity. This paper primarily focuses on work aimed at reducing the Equivalent System Mass of a Trash Compaction Processing System via a focus on improving the system�s thermal efficiency.Item Source Contaminant Control System Design, Operation, and Testing for the Trash Compaction and Processing System(2023 International Conference on Environmental Systems, 2023-07-16) Young, Janine; Pace, Gregory; Trieu, Serena; Martin, Kevin; Richardson, Tra-My Justine; Sepka, Steve; Parodi, JurekThe Trash Compaction and Processing System (TCPS) aims to reduce volume, biologically safen, physically stabilize, manage effluents, and recover resources from astronaut trash in the International Space Station (ISS). This process involves heating the trash to high temperatures, which in turn releases gaseous contaminants. Effluent management scenarios involve releasing these gases back to the ISS cabin after processing and/or directly venting these gases out to space via the Vacuum Exhaust System (VES). Concerns for recovering the gases back to cabin are crew health, safety, and spacecraft environmental impact. The Heat Melt Compactor (HMC) at NASA Ames Research Center (ARC) serves as a test system that supports TCPS development by conducting risk reduction activities associated with an ISS flight demonstration. Previous gas effluent studies were conducted on the HMC. The results consisted of contaminants from the trash exhaust to exceed Spacecraft Maximum Allowable Concentrations (SMAC), which are selected airborne contaminants that can elicit toxicity symptoms to crewmembers via exposure. The Source Contaminant Control System (SCCS) aims to reduce that risk by converting the contaminants into carbon dioxide (CO2) and water (H2O) vapor. The SCCS is composed of a carbon adsorbent bed, to avoid catalyst poisoning, and a catalytic oxidizer (CatOx), which promotes oxidation of the contaminants to CO2 and H2O. In turn, the gases coming out of the SCCS should be compatible to the ISS cabin and systems such as the Trace Contaminant Control System (TCCS). Preparation for SCCS testing alongside the HMC Gen 3 are currently underway at ARC. The main objectives are to evaluate CatOx efficiency by CO2 conversion and characterize effectiveness of removal by comparing contaminant results before and after CatOx. This paper will report on the SCCS design, operation, and testing with results.Item The Trash Compaction Processing System (TCPS) Technology Demonstration and Risk Reduction Updates FY23-FY24(2024 International Conference on Environmnetal Systems, 2024-07-21) Richardson, Tra-My; Sepka, Steve; Martin, Kevin; Borrego, Melissa; Ewert, Michael; McKinley, Melissa; Trieu, Serena; Pace, Gregory; Young, Janine; White, DouglasThe Next STEP Phase B Trash Compaction Processing System (TCPS) is being developed for a technology demonstration on the International Space Station (ISS) to process common consumables spacecraft trash such as clothing and food packing to reduce the volume, recover the water, safen, and shaped the trash for storage, jettison, reuse (e.g. radiation shielding) and recycling. Sierra Space is developing the flight demonstration hardware and National Aeronautics and Space Administration (NASA) continues to conduct risk reduction activities to vet operational scenarios ensure successful on-orbit tests. After the flight demonstration on ISS, the TCPS can be infused into NASA short- and long-term missions. This paper will discuss the rational for the updated requirement definitions outlined in the 2023 International Conference on Environmental System TCPS paper and the risk reduction activities. In addition, drawing from lesson learned in the development of the TCPS, a discussion of other compression technologies will be introduced.Item The Trash Compaction Processing System (TCPS) Technology Demonstrations Science Objectives and Requirement Definitions(2023 International Conference on Environmental Systems, 2023-07-16) Richardson, Tra-My Justine; Lee, Jeffrey; Sepka, Steve; Martin, Kevin; Ewert, Michael; McKinley, Melissa; Trieu, Serena; Pace, Gregory; Young, Janine; White, DouglasThroughout the Next STEP Phase A and Phase B, the Trash Compaction Processing System (TCPS) is being developed for a technology demonstration on the International Space Station in 2025. For Phase A, two contractors built the proof-of-concept hardware. One contractor was chosen to build the TD hardware for Phase B. Both Phase A lesson learned and risk reduction activities at Ames Research Center were used to write the TD science objectives, scope, and requirements. The work at ARC aims to retire technical risks and provide design data to TCPS developers and the ISS system integrators. This paper will summarize the lessons learned from the proof-of-concept hardware and the risk reduction activities and how these lessons learned form the TD requirement matrix.Item Updated Analysis of the Trash Compaction and Processing System: Water Collected from Trash, Evaluation of the Source Contaminant Control System, and Zotek® F30 Foam Processing(2024 International Conference on Environmnetal Systems, 2024-07-21) Young, Janine; Trieu, Serena; Pace, Gregory; Sepka, Steve; Richardson, Tra-My Justine; Martin, KevinThe Trash Compaction and Processing System (TCPS) aims to reduce volume, biologically safen, physically stabilize, manage effluents, and recover resources from astronaut trash in the International Space Station (ISS). At NASA Ames Research Center (ARC), there are two test systems: the Heat Melt Compactor (HMC), which compacts the trash into a tile with temperature and pressure, and the Source Contaminant Control System (SCCS), which is the gas management subsystem aimed to reduce contaminants by converting them into carbon dioxide (CO2) and water (H2O) vapor. Both the HMC and SCCS serve as test systems that support TCPS development by conducting risk reduction activities associated with an ISS technology demonstration. In this paper, the risk reduction activities discussed are the testing of different trash models for operational scenarios in the HMC, investigating the water extracted from those trash models, and managing the gaseous effluents from the trash via contaminant conversion through the SCCS. The HMC has undergone several tests of different trash models and cases in which a containment bag is used or not. For the first topic, this paper will analyze the water collected and recovered from these tests and analyze the effect of specific trash containment bags. For the second topic, this paper will individually evaluate the carbon bed and catalytic oxidizer (CatOx) to understand what components the carbon bed removes and what contaminants are converted in the CatOx. For the third and final topic, this paper will discuss Zotek� F30 foam processing in the HMC unit and testing verification in correlation to defined TCPS requirements. A foam model was added to reduce the volume of foam that take up space in the ISS. Overall, this paper is a compilation and an updated analysis of tests conducted in the lab-scale TCPS at ARC within the past year.