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Anderson, Molly

Publications and source records attributed to Anderson, Molly.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

A Trade Study of Two Membrane-Aerated Biological Water Processors

Biologically based systems are under evaluation as primary water processors for next generation life support systems due to their low power requirements and their inherent regenerative nature. This paper will summarize the results of two recent studies involving membrane aerated biological water processors and present results of a trade study comparing the two systems with regards to waste stream composition, nutrient loading and system design. Results of optimal configurations will be presented.

Allada, Ram↗
NASA NTRS2011

Dynamic Modeling of Process Technologies for Closed-Loop Water Recovery Systems

Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents dynamic simulations of chemical process for primary processor technologies including: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system, the Wiped-Film Rotating Disk (WFRD), and post-distillation water polishing processes such as the Volatiles Removal Assembly (VRA) that were developed using the Aspen Custom Modeler and Aspen Plus process simulation tools. The results expand upon previous work for water recovery technology models and emphasize dynamic process modeling and results. The paper discusses system design, modeling details, and model results for each technology and presents some comparisons between the model results and available test data. Following these initial comparisons, some general conclusions and forward work are discussed.

Allada, Rama Kumar↗
NASA NTRS2010

Air Stripping Designs and Reactive Water Purification Processes for the Lunar Surface

Air stripping designs are considered to reduce the presence of volatile organic compounds in the purified water. Components of the wastewater streams are ranked by Henry's Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Distillation processes are modeled in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates. An evaluation of reactive distillation and air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

Boul, Peter J.↗
NASA NTRS2010

Altair Lander Life Support: Requirements Analysis Cycles 1 and 2

Life support systems are a critical part of human exploration beyond low earth orbit. NASA's Altair Lunar Lander has unique missions to perform and will need a unique life support system to complete them. Initial work demonstrated a feasible minimally -functional Lander design. This work was completed in Design Analysis Cycles (DAC) 1, 2, and 3 were reported in a previous paper'. On October 21, 2008, the Altair project completed the Mission Concept Review (MCR), moving the project into Phase A. In Phase A activities, the project is preparing for the System Requirements Review (SRR). Altair has conducted two Requirements Analysis Cycles (RACs) to begin this work. During this time, the life support team must examine the Altair mission concepts, Constellation Program level requirements, and interfaces with other vehicles and spacesuits to derive the right set of requirements for the new vehicle. The minimum functionality design meets some of these requirements already and can be easily adapted to meet others. But Altair must identify which will be more costly in mass, power, or other resources to meet. These especially costly requirements must be analyzed carefully to be sure they are truly necessary, and are the best way of explaining and meeting the true need. If they are necessary and clear, they become important mass threats to track at the vehicle level. If they are not clear or do not seem necessary to all stakeholders, Altair must work to redefine them or push back on the requirements writers. Additionally, the life support team is evaluating new technologies to see if they are more effective than the existing baseline design at performing necessary functions in Altair's life support system.

Anderson, Molly↗
NASA NTRS2010

Distillation Designs for the Lunar Surface

Gravity-based distillation methods may be applied to the purification of wastewater on the lunar base. These solutions to water processing are robust physical separation techniques, which may be more advantageous than many other techniques for their simplicity in design and operation. The two techniques can be used in conjunction with each other to obtain high purity water. The components and feed compositions for modeling waste water streams are presented in conjunction with the Aspen property system for traditional stage distillation. While the individual components for each of the waste streams will vary naturally within certain bounds, an analog model for waste water processing is suggested based on typical concentration ranges for these components. Target purity levels for recycled water are determined for each individual component based on NASA s required maximum contaminant levels for potable water Optimum parameters such as reflux ratio, feed stage location, and processing rates are determined with respect to the power consumption of the process. Multistage distillation is evaluated for components in wastewater to determine the minimum number of stages necessary for each of 65 components in humidity condensate and urine wastewater mixed streams.

Boul, Peter J.↗
NASA NTRS2010

Simulation and Optimization of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

Controlling carbon dioxide (CO2) and humidity levels in a spacesuit is critical to ensuring both the safety and comfort of an astronaut during extra-vehicular activity (EVA). Traditionally, this has been accomplished utilizing non-regenerative lithium hydroxide (LiOH) or regenerative metal oxide (MetOx) canisters which pose a significant weight burden. Although such technology enables air revitalization, the volume requirements to store the waste canisters as well as the mass to transport multiple units become prohibitive as mission durations increase. Consequently, motivation exists toward developing a fully regenerative technology for environmental control. The application of solid amine materials with vacuum swing adsorption technology has shown the capacity to control CO2 and concomitantly manage humidity levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Experimental results for full-size and sub-scale test articles have been collected and are described herein. In order to accelerate the developmental efforts, an axially-dispersed plug ow model with an accompanying energy balance has been established and correlated with the experimental data. The experimental and simulation results display good agreement for a variety of ow rates (110-170 SLM), replicated metabolic challenges (100-590 Watts), and atmosphere pressures under consideration for the spacesuit (248 and 760 mm Hg). The relationship between swing adsorption cycles for an outlet criterion of 6.0 mm Hg of CO2 partial pressure has been established for each metabolic challenge. In addition, variable metabolic profiles were imposed on the test articles in order to assess the ability of the technology to transition to new operational constraints. The advent of the model provides the capacity to apply computer-aided engineering practices to support the ongoing efforts to optimize and mature this technology for future application to space exploration.

Swickrath, Michael J.↗
NASA NTRS2010

Altair Lander Life Support: Design Analysis Cycles 4 and 5

Life support systems are a critical part of human exploration beyond low earth orbit. NASA s Altair Lunar Lander team is pursuing efficient solutions to the technical challenges of human spaceflight. Life support design efforts up through Design Analysis Cycle (DAC) 4 focused on finding lightweight and reliable solutions for the Sortie and Outpost missions within the Constellation Program. In DAC-4 and later follow on work, changes were made to add functionality for new requirements accepted by the Altair project, and to update the design as knowledge about certain issues or hardware matured. In DAC-5, the Altair project began to consider mission architectures outside the Constellation baseline. Selecting the optimal life support system design is very sensitive to mission duration. When the mission goals and architecture change several trade studies must be conducted to determine the appropriate design. Finally, several areas of work developed through the Altair project may be applicable to other vehicle concepts for microgravity missions. Maturing the Altair life support system related analysis, design, and requirements can provide important information for developers of a wide range of other human vehicles.

Anderson, Molly↗
NASA NTRS2010

Testing and Results of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

A principal concern for extravehicular activity (EVA) space suits is the capability to control carbon dioxide (CO2) and humidity (H2O) for the crewmember. The release of CO2 in a confined or unventilated area is dangerous for human health and leads to asphyxiation; therefore, CO2 and H2O become leading factors in the design and development of the spacesuit. An amine-based CO2 and H2O vapor sorbent for use in pressure-swing re-generable beds has been developed by Hamilton Sundstrand. The application of solid-amine materials with vacuum swing adsorption technology has shown the capacity to concurrently manage CO2 and H2O levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Two prototype solid amine-based systems, known as rapid cycle amine (RCA), were designed to continuously remove CO2 and H2O vapor from a flowing ventilation stream through the use of a two-bed amine based, vacuum-swing adsorption system. The Engineering and Science Contract Group (ESCG) RCA is the first RCA unit implementing radial flow paths, whereas the Hamilton Sundstrand RCA was designed with linear flow paths. Testing was performed in a sea-level pressure environment and a reduced-pressure environment with simulated human metabolic loads in a closed-loop configuration. This paper presents the experimental results of laboratory testing for a full-size and a sub-scale test article. The testing described here characterized and evaluated the performance of each RCA unit at the required Portable Life Support Subsystem (PLSS) operating conditions. The test points simulated a range of crewmember metabolic rates. The experimental results demonstrate the ability of each RCA unit to sufficiently remove CO2 and H2O from a closed loop ambient or subambient atmosphere.

McMillin, Summer↗
NASA NTRS2009

ALSSAT Development Status

The development of the Advanced Life Support (ALS) Sizing Analysis Tool (ALSSAT) using Microsoft(Registered TradeMark) Excel was initiated by the Crew and Thermal Systems Division (CTSD) of Johnson Space Center (JSC) in 1997 to support the ALS and Exploration Offices in Environmental Control and Life Support System (ECLSS) design and studies. It aids the user in performing detailed sizing of the ECLSS for different combinations of the Exploration Life support (ELS) regenerative system technologies. This analysis tool will assist the user in performing ECLSS preliminary design and trade studies as well as system optimization efficiently and economically. The latest ALSSAT related publication in ICES 2004 detailed ALSSAT s development status including the completion of all six ELS Subsystems (ELSS), namely, the Air Management Subsystem, the Biomass Subsystem, the Food Management Subsystem, the Solid Waste Management Subsystem, the Water Management Subsystem, and the Thermal Control Subsystem and two external interfaces, including the Extravehicular Activity and the Human Accommodations. Since 2004, many more regenerative technologies in the ELSS were implemented into ALSSAT. ALSSAT has also been used for the ELS Research and Technology Development Metric Calculation for FY02 thru FY06. It was also used to conduct the Lunar Outpost Metric calculation for FY08 and was integrated as part of a Habitat Model developed at Langley Research Center to support the Constellation program. This paper will give an update on the analysis tool s current development status as well as present the analytical results of one of the trade studies that was performed.

Yeh, H. Y. Jannivine↗
NASA NTRS2009

Altair Lander Life Support: Design Analysis Cycles 1, 2, and 3

NASA is working to develop a new lunar lander to support lunar exploration. The development process that the Altair project is using for this vehicle is unlike most others. In Lander Design Analysis Cycle 1 (LDAC-1), a single-string, minimum functionality design concept was developed, including life support systems for different vehicle configuration concepts, first for a combination of an ascent vehicle and a habitat with integral airlocks, and then for a combined ascent vehicle-habitat with a detachable airlock. In LDAC-2, the Altair team took the ascent vehicle-habitat with detachable airlock and analyzed the design for the components that were the largest contributors to the risk of loss of crew (LOC). For life support, the largest drivers were related to oxygen supply and carbon dioxide control. Integrated abort options were developed at the vehicle level. Many life support failures were not considered to result in LOC because they had a long enough time to effect that abort was considered a feasible option to safely end the mission before the situation became life threatening. These failures were then classified as loss of mission (LOM) failures. Many options to reduce LOC risk were considered, and mass efficient solutions to the LOC problems were added to the vehicle design at the end of LDAC-2. In LDAC-3, the new design was analyzed for large contributors to the risk of LOM. To avoid ending the mission early or being unable to accomplish goals like performing all planned extravehicular activities (EVAs), various options were assessed for their combination of risk reduction and mass cost. This paper outlines the major assumptions, design features, and decisions related to the development of the life support system for the Altair project through LDAC-3.

Anderson, Molly↗
NASA NTRS2009

Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

Boul, Peter J.↗
NASA NTRS2009

Distillation and Air Stripping Designs for the Lunar Surface

Air stripping and distillation are two different gravity-based methods, which may be applied to the purification of wastewater on the lunar base. These gravity-based solutions to water processing are robust physical separation techniques, which may be advantageous to many other techniques for their simplicity in design and operation. The two techniques can be used in conjunction with each other to obtain high purity water. The components and feed compositions for modeling waste water streams are presented in conjunction with the Aspen property system for traditional stage distillation models and air stripping models. While the individual components for each of the waste streams will vary naturally within certain bounds, an analog model for waste water processing is suggested based on typical concentration ranges for these components. Target purity levels for the for recycled water are determined for each individual component based on NASA s required maximum contaminant levels for potable water Distillation processes are modeled separately and in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Optimum parameters such as reflux ratio, feed stage location, and processing rates are determined with respect to the power consumption of the process. Multistage distillation is evaluated for components in wastewater to determine the minimum number of stages necessary for each of 65 components in humidity condensate and urine wastewater mixed streams. Components of the wastewater streams are ranked by Henry s Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates.

Boul, Peter J.↗
NASA NTRS2009

Altair Lander Life Support: Requirement Analysis Cycles 1 and 2

Life support systems are a critical part of human exploration beyond low earth orbit. NASA s Altair Lunar Lander has unique missions to perform and will need a unique life support system to complete them. Initial work demonstrated a feasible minimally-functional Lander design. This work was completed in Design Analysis Cycles (DAC) 1, 2, and 3 were reported in a previous paper. On October 21, 2008, the Altair project completed the Mission Concept Review (MCR), moving the project into Phase A. In Phase A activities, the project is preparing for the System Requirements Review (SRR). Altair has conducted two Requirements Analysis Cycles (RACs) to begin this work. During this time, the life support team must examine the Altair mission concepts, Constellation Program level requirements, and interfaces with other vehicles and spacesuits to derive the right set of requirements for the new vehicle. The minimum functionality design meets some of these requirements already and can be easily adapted to meet others. But Altair must identify which will be more costly in mass, power, or other resources to meet. These especially costly requirements must be analyzed carefully to be sure they are truly necessary, and are the best way of explaining and meeting the true need. If they are necessary and clear, they become important mass threats to track at the vehicle level. If they are not clear or do not seem necessary to all stakeholders, Altair must work to redefine them or push back on the requirements writers. Additionally, the life support team is evaluating new technologies to see if they are more effective than the existing baseline design at performing necessary functions in Altair s life support system.

Anderson, Molly↗
NASA NTRS2008

Life Support Systems for Lunar Landers

Engineers designing life support systems for NASA s next Lunar Landers face unique challenges. As with any vehicle that enables human spaceflight, the needs of the crew drive most of the lander requirements. The lander is also a key element of the architecture NASA will implement in the Constellation program. Many requirements, constraints, or optimization goals will be driven by interfaces with other projects, like the Crew Exploration Vehicle, the Lunar Surface Systems, and the Extravehicular Activity project. Other challenges in the life support system will be driven by the unique location of the vehicle in the environments encountered throughout the mission. This paper examines several topics that may be major design drivers for the lunar lander life support system. There are several functional requirements for the lander that may be different from previous vehicles or programs and recent experience. Some of the requirements or design drivers will change depending on the overall Lander configuration. While the configuration for a lander design is not fixed, designers can examine how these issues would impact their design and be prepared for the quick design iterations required to optimize a spacecraft.

Anderson, Molly↗
NASA NTRS2008

High-Pressure Oxygen Generation for Outpost EVA

Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The emitted infrared (IR) heat flux from the lunar surface varies drastically from the light side to the dark side of the moon. Due to the extremely high incident IR flux, especially at low beta angles, a radiator is oftentimes unable to reject the vehicle heat load throughout the entire lunar orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor, storing thermal energy when the radiator is unable to reject the required heat load. The stored energy is then removed from the PCM heat exchanger when the environment is more benign. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration Low Lunar Orbit missions. The Advanced Thermal Control project at JSC is completing a PCM heat exchanger life test to determine whether further technology development is warranted. The life test is being conducted on four nPentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 meltfreeze cycles will be performed and reported in the current document.

Jeng, Frank↗
NASA NTRS2007

Testing of the Multi-Fluid Evaporator Engineering Development Unit

Hamilton Sundstrand is under contract with the NASA Johnson Space Center to develop a scalable, evaporative heat rejection system called the Multi-Fluid Evaporator (MFE). It is being designed to support the Orion Crew Module and to support future Constellation missions. The MFE would be used from Earth sea level conditions to the vacuum of space. The current Shuttle configuration utilizes an ammonia boiler and flash evaporator system to achieve cooling at all altitudes. The MFE system combines both functions into a single compact package with significant weight reduction and improved freeze-up protection. The heat exchanger core is designed so that radial flow of the evaporant provides increasing surface area to keep the back pressure low. The multiple layer construction of the core allows for efficient scale up to the desired heat rejection rate. The full scale MFE prototype will be constructed with four core sections that, combined with a novel control scheme, manage the risk of freezing the heat exchanger cores. A sub-scale MFE engineering development unit (EDU) has been built, and is identical to one of the four sections of a full scale prototype. The EDU has completed testing at Hamilton Sundstrand. The overall test objective was to determine the thermal performance of the EDU. The first set of tests simulated how each of the four sections of the prototype would perform by varying the chamber pressure, evaporant flow rate, coolant flow rate and coolant temperature. A second set of tests was conducted with an outlet steam header in place to verify that the outlet steam orifices prevent freeze-up in the core while also allowing the desired thermal turn-down ratio. This paper discusses the EDU tests and results.

Quinn, Gregory↗
NASA NTRS2006

Reduced Pressure Atmosphere Impacts on Life Support and Internal Thermal Systems

Selecting the appropriate atmosphere for a spacecraft and mission is a complicated problem. NASA has previously used atmospheres from Earth normal composition and pressure to pure oxygen at low pressures. Future exploration missions will likely strike a compromise somewhere between the two, trying to balance operation impacts on EVA, safety concerns for flammability and health risks, life science and physiology questions, and other issues. Life support systems and internal thermal control systems are areas that will have to respond to changes in the atmospheric composition and pressure away from the Earthlike conditions currently used on the International Space Station. This paper examines life support and internal thermal control technologies currently in use or in development to find what impacts in design, efficiency and performance, or feasibility might be expected. Understanding these changes should be helpful in producing better results during future trade studies or mission analyses.

Anderson, Molly↗