Browsing by Author "Nur, Mononita"

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Advanced Oxygen Recovery via Series-Bosch Technology
(45th International Conference on Environmental Systems, 2015-07-12) Abney, Morgan B.; Mansell, J. Matthew; Atkins, Bobby; Evans, Chris; Nur, Mononita; Beassie, Rockford D.
Advanced oxygen recovery life support for Martian transit and surface missions constitutes a variety of possible architectures. Over the last several years, NASA has pursued development of a two-step Bosch-based system called Series-Bosch (S-Bosch) to enable maximum recovery of oxygen from metabolic carbon dioxide. The first step of the process involves the Reverse Water-Gas Shift (RWGS) reaction. Two RWGS reactors, one developed at NASA and the other developed at Precision Combustion, Inc. have been assembled for the S-Bosch. The RWGS reactors were each tested to evaluate and compare general operational performance and fouling resistance. A down-select was completed to identify the reactor to be used in an integrated S-Bosch system. The second step in the S-Bosch process is carbon deposition. A carbon formation reactor (CFR) based on Martian regolith simulant as a catalyst was designed and tested for performance. Because the regolith will only be available once the crew arrives on the Martian surface, a second catalyst was evaluated for transit phases. Finally, integrated testing of an S-Bosch system was completed, leading to a technology readiness level (TRL) advancement of the S-Bosch system to TRL 4. The results of the RWGS down-select, CFR testing, and TRL evaluation are reported and discussed.
Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production
(44th International Conference on Environmental Systems, 2014-07-13) Caraccio, Anne J.; Devor, Robert W.; Hintze, Paul E.; Muscatello, Anthony C.; Nur, Mononita
The Trash to Gas (TtG) project investigated technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA’s Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluated catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.
Comprehensive Digital Twin of a Microfluidic Electrochemical Reactor to Optimize the Electrochemical-based Recovery of O2 from Metabolic CO2
(2024 International Conference on Environmnetal Systems, 2024-07-21) Dominguez, Jesus A.; McCall, Shannon; Reidy, Lorlyn; Nur, Mononita; Brown, Brittany; Dennis, Brian; Chanmanee, Wilaiwan; Fillion, Joseph; Ollenburg, Kathryn
Future long-duration missions will require a sustainable and efficient system capable of yielding a minimum of 75% O2 recovery from metabolic CO2 to achieve self-sufficiency for long space missions beyond Earth's low orbit. A Microfluidic Electrochemical Reactor (MFECR) development effort to electrochemically recover O2 from CO2 is underway at NASA Marshall Space Flight Center (MSFC) to increase current O2 recovery efficiency and reduce air revitalization (AR) system complexity at the International Space Station (ISS) habitat and future long missions. The authors have developed and deployed a comprehensive 3D multiphysics model that thoroughly replicates the actual configuration and fluid/material domains of the MFECR. This model's electrochemical physics consists of multicomponent-multiphase electrochemical-driven reactions leading to CO2 conversion to C2H4 and CO along with the formation of H2 on the cathode in parallel with the generation of O2 and H2O on the anode. This electrochemical model is coupled with all the physics phenomena involved in the process, including but not limited to fluid and non-ideal mass transfer of reactant and product species in free/porous media, convective/conduction/radiative heat transfer, and conduction of DC electrical current with Joule heating generation. The model has proved to be an essential optimization tool using the O2 conversion from CO2 as the objective function and the dimensions of three different Engineering Design Unit (EDU) geometry layouts and two inlet process conditions as input variables. The three MFECR geometry layouts include one without serpentine paths (plain) and two with serpentines leading to four and twelve paths, respectively. The two inlet process conditions include CO2 flow rate and temperature. The MFECR's test stand is fully automated and equipped with several inline measurements (flow, pressure, temperature, pH, component concentration) systems on all six MFECR's IO streams, allowing reliable experimental validation of the model and parametric determination of all electrochemical reactions.
Developing Methods for Biofilm Control in Microgravity for a Water Recovery System
(2020 International Conference on Environmental Systems, 2020-07-31) Velez, Yo-Ann; Carter, Donald; Nur, Mononita; Angle, Geoffrey
Biofilm growth is a significant concern for NASA’s current and future water systems. The International Space Station (ISS) Water Processor Assembly (WPA) produces potable water from a combination of humidity condensate and urine distillate. After two years of operation, the WPA experienced a significant failure (clogged solenoid valve) due to biofilm growth in the waste tank that collects these two waste streams. The WPA waste tank now requires significant management to prevent biofilm from impacting downstream components. This issue is magnified for future NASA manned missions due to the need to place the vehicle’s life support system in a dormant state during uncrewed operations (e.g., when vehicle is in Mars orbit during surface mission). The urine distillate and humidity condensate are also expected to be an issue during dormancy, especially where these waste streams originate (the condenser in the Distillation Assembly of the Urine Processor) and the Water Separators that collects and delivers the humidity condensate removed from the atmosphere. To address these concerns, NASA is performing an ongoing research task to a) identify viable methods for inhibiting growth of biofilms, b) develop design solutions for implementing these various methods, c) perform a trade study to select methods (taking into account the design solutions), and d) evaluate effectiveness in ground test prior future missions This paper provides an overview of the current status on this effort.
Evaluation of Biofilm Inhibitors for the Environmental Control and Life Support Water Recovery System
(49th International Conference on Environmental Systems, 2019-07-07) Williams, Wendy; Carter, Layne; Nur, Mononita; Burzell, Cynthia
Hydrogen Purification and Recycling for an Integrated Oxygen Recovery System Architecture
(46th International Conference on Environmental Systems, 2016-07-10) Abney, Morgan; Greenwood, Zach; Wall, Terry; Miller, Lee; Nur, Mononita; Wheeler, Richard; Preston, Joshua
The United States Atmosphere Revitalization life support system on the International Space Station (ISS) performs several services for the crew including oxygen generation, trace contaminant control, carbon dioxide (CO2) removal, and oxygen recovery. Oxygen recovery is performed using a Sabatier reactor developed by Hamilton Sundstrand, wherein CO2 is reduced with hydrogen in a catalytic reactor to produce methane and water. The water product is purified in the Water Purification Assembly and recycled to the Oxygen Generation Assembly (OGA) to provide O2 to the crew. This architecture results in a theoretical maximum oxygen recovery from CO2 of ~54% due to the loss of reactant hydrogen in Sabatier-produced methane that is currently vented outside of ISS. Plasma Methane Pyrolysis technology (PPA), developed by Umpqua Research Company, provides the capability to further close the Atmosphere Revitalization oxygen loop by recovering hydrogen from Sabatier-produced methane. A key aspect of this technology approach is to purify the hydrogen from the PPA product stream which includes acetylene, unreacted methane and byproduct water and carbon monoxide. In 2015, four sub-scale hydrogen separation systems were delivered to NASA for evaluation. These included two electrolysis single-cell hydrogen purification cell stacks developed by Sustainable Innovations, LLC, a sorbent-based hydrogen purification unit using microwave power for sorbent regeneration developed by Umpqua Research Company, and a LaNi4.6Sn0.4 metal hydride produced by Hydrogen Consultants, Inc. Here we report the results of these evaluations, discuss potential architecture options, and propose future work.
A Preliminary Modeling Study of Biofilm Accumulation in the Water Recovery System
(2020 International Conference on Environmental Systems, 2020-07-31) Diaz, Angie; Li, Wenyan; Irwin, Tesia; Calle, Luz; Angle, Geoffrey; Velez Justiniano, Yo-Ann; Nur, Mononita; Callahan, Michael
Bacterial biofilms are ubiquitous in wastewater systems on earth and in spacecraft, such as in the International Space Station (ISS) wastewater processing assembly (WPA), where they cause problems in the tank, solenoid valves, and pipelines. Downstream filter applications, tank cycling, and regular biocide water flushing have been used to control biofilm accumulation on board the ISS. Biofilm control is expected to be a challenge for long-term missions with a dormancy period of up to a year, as stagnant water systems are highly susceptible to biofilm growth. Flushing of the system with biocidal water has been proposed to avoid biomass problems for long-term missions. To validate the proposed flush method, a mathematical model, based on the metabolism maintenance rate of bacteria, is being developed to understand the current biofilm accumulation rate in the ISS WPA system and to calculate the biomass production rate under dormancy-like conditions. This method of quantification of biofilm can be applied as a function of nutrient inputs to guide the selection and optimization of biofilm mitigation approaches. The method can also be helpful in understanding, defining, quantifying, visualizing, and simulating the state of the water processing system during operation and after dormancy.
Reliable and Efficient Electrochemical Recovery of O2 from Metabolic CO2 at the International Space Station (ISS)
(2024 International Conference on Environmnetal Systems, 2024-07-21) Dominguez, Jesus A.; Reidy, Lorlyn; Nur, Mononita; Crawford, Kagen; Brown, Brittany; Dennis, Brian; Chanmanee, Wilaiwan; Fillion, Joseph; Ollenburg, Kathryn; McCall, Shannon
Maximum oxygen (O2) recovery from metabolic carbon dioxide (CO2) is desired for future long-duration missions beyond Low Earth Orbit. The O2 recovery for the Environmental Control and Life Support System (ECLSS) at the International Space Station (ISS), presently limited to 50% (Sabatier), must be highly reliable and efficient and recover a minimum of 75% O2 from metabolic CO2. An alternative technology development effort currently underway at NASA Marshall Space Flight Center via a Macro-fluidic Electrochemical Reactor (MFECR) approach has the potential to increase O2 recovery significantly and reduce the complexity of the ECLSS O2 recovery at the ISS as it would replace three pieces, the CO2 Reduction Assembly (CRA) (Sabatier reactor), the Oxygen Generation Assembly (OGA), and the Plasma Pyrolysis Assembly (PPA). The MFECR's electrochemical process generates ethylene (C2H4) and carbon monoxide (CO) instead of methane (CH4) (Sabatier) as a byproduct, eliminating the need for further dehydrogenation through the PPA. As in the OGA, the MFECR's electrochemical process generates O2 and hydrogen (H2) from the water electrolysis process. MSFC and the University of Texas in Arlington have jointly designed and fabricated/upgraded an MFECR's single cell that operates at ambient conditions and utilizes a catalyst highly selective on reducing CO2 to C2H4 and CO at the cathode. This approach is expected to substantially improve the ISS ECLSS sustainability and reduce power and weight requirements as the MFECR would replace three and potentially four units currently installed in the ISS. In this paper, the authors discuss the outcome of preliminary tests, the current development, the evaluation efforts on different alternatives for the cathode and the anode configurations, the use of MFECR's digital twin to upgrade its design at an engineering development unit (EDU) scale, and the evaluation efforts on different electrolyte alternatives and alkalinity effect.
Upgrades to the International Space Station Water Processor Assembly
(48th International Conference on Environmental Systems, 2018-07-08) Kayatin, Matthew; Williamson, Jill; Nur, Mononita; Carter, Donald
The International Space Station Water Processor Assembly provides contaminant control and deionization functions to the Water Recovery System. The Water Processor Assembly presently utilizes sorbent-based Multifiltration Beds and a downstream Catalytic Reactor for these operations. Upgrades and process improvements are desired to improve performance, increase reliability, and decrease consumable resupply. To this end, reverse osmosis membrane separation technologies were evaluated to reduce influent contaminant loads, candidate additives to inhibit wastewater biofilm formation and growth were studied, and life stability testing was completed for a recently developed high-activity catalyst. The performance and applicability of these new technologies within the Water Processor Assembly, as well as their suitability for exploration missions, are discussed herein.
Upgrades to the International Space Station Water Recovery System
(47th International Conference on Environmental Systems, 2017-07-16) Kayatin, Matthew; Pruitt, Jennifer; Nur, Mononita; Takada, Kevin; Carter, Donald
The International Space Station (ISS) Water Recovery System (WRS) includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WRS produces potable water from a combination of crew urine (first processed through the UPA), crew latent, and Sabatier product water. Though the WRS has performed well since operations began in November 2008, several modifications have been identified to improve the overall system performance. These modifications aim to reduce resupply and improve overall system reliability, which is beneficial for the ongoing ISS mission as well as for future NASA manned missions. The following paper details efforts to improve the WPA through the use of reverse osmosis membrane technology to reduce the resupply mass of the WPA Multifiltration Bed and improved catalyst for the WPA Catalytic Reactor to reduce the operational temperature and pressure. For the UPA, this paper discusses progress on various concepts for improving the reliability of the system, including the implementation of a more reliable drive belt, improved methods for managing condensate in the stationary bowl of the Distillation Assembly, and evaluating upgrades to the UPA vacuum pump.