Search Results

The Vapor Phase Catalytic Ammonia Removal (VPCAR) technology has been previously discussed as a viable option for the Exploration Water Recovery System. This technology integrates a phase change process with catalytic oxidation in the vapor phase to produce potable water from exploration mission wastewaters. A developmental prototype VPCAR was designed, built and tested under funding provided by a National Research Announcement (NRA) project. The core technology, a Wiped Film Rotating Device (WFRD) was provided by Water Reuse Technologies under the NRA, whereas Hamilton Sundstrand Space Systems International performed the hardware integration and acceptance test of the system. Personnel at the Ames Research Center performed initial systems test of the VPCAR using ersatz solutions. To assess the viability of this hardware for Exploration Life Support (ELS) applications, the hardware has been modified and tested at the MSFC ECLS Test Facility.

Shortly after installation of the service and performance heat exchanger (SPCU HX) in 2001, samples collected from the coolant fluid indicated the presence of nickel accompanied by a subsequent decrease in phosphate concentration along with a high microbial load. When the SPCU HX was replaced and evaluated post-flight, it was expected that the heat exchanger would have significant biofilm and corrosion present given the composition of the coolant fluid; however, there was no evidence of either. Early results from two experiments imply that the heat exchanger materials themselves are inhibiting biofilm formation. This paper discusses the results of one set of experiments and puts forward the inhibition of quorum sensing as a possible mechanism for the lack of biofilm formation.

We present the development of a semiconductor diode laser spectral absorption based gas species sensor for oxygen concentration measurements, intended for life support system monitoring and control applications. Employing a novel self-compensating, noise cancellation detection approach, we experimentally demonstrate better than 1% accuracy, linearity, and stability for monitoring breathing air conditions with 0.2 second response time. We also discuss applications of this approach to CO2 sensing.

Space environmental control systems must control cabin temperature and humidity. This can be achieved by transferring the heat load to a circulating coolant, condensing the humidity, and separating the condensate from the air stream. In addition, environmental control systems may be required to remove particulate matter from the air stream. An assembly comprised of a filter, a condensing heat exchanger, a thermal control valve, and a liquid carryover sensor, is used to achieve all these requirements. A condensing heat exchanger and filter assembly (CHXFA) is being developed and manufactured by SECAN/AlliedSignal under a contract from Dornier Daimler-Benz as part of a European Space Agency program. The CHXFA is part of the environmental control system of the Columbus Orbital Facility (COF), the European laboratory module of the International Space Station (ISS).

The dual membrane gas trap filter is utilized in the internal thermal control system (ITCS) as part of the pump package assembly to remove non-condensed gases from the ITCS coolant. This improves pump performance and prevents pump cavitation. The gas trap also provides the capability to vent air that is Ingested into the ITCS during routine maintenance and replacement of the International Space Station (ISS) system orbital replacement units. The gas trap is composed of two types of membranes that are formed into a cylindrical module and then encased within a titanium housing. The non-condensed gas that is captured is then allowed to escape through a vent tube in the gas trap housing.

Advanced life support flight experiments have been conceptualized for the International Space Station (ISS). Two of the experiments, a high pressure oxygen generator and a carbon dioxide reduction subsystem, offer high payback potential to the ISS program. This paper documents the cost-benefit analyses for these two experiments.

A test has been completed at NASA's Marshall Space Flight Center (MSFC) to evaluate the Water Recovery and Management (WRM) system and Waste Management (WM) urinal design for the United States On-Orbit Segment (USOS) of the International Space Station (ISS). Potable and urine reclamation processors were integrated with waste water generation equipment and successfully operated for a total of 128 days in recipient mode configuration to evaluate the accumulation of contaminants in the water system and to assess the performance of various modifications to the WRM and WM hardware. No accumulation of contaminants were detected in the product water over the course of the recipient mode test. An additional 18 days were conducted in donor mode to assess the ability of the system to removal viral contaminants, to monitor the breakthrough of organic contaminants through the multifiltration bed, and for resolving anomalies that occurred during the test.

A two year test program has been initiated to evaluate the effects of extended duration operation on a solid polymer electrolyte Oxygen Generator Assembly (OGA); in particular the cell stack and membrane phase separators. As part of this test program, the OGA was integrated into the Marshall Space Flight Center (MSFC) Water Recovery Test (WRT) Stage 10, a six month test, to use reclaimed water directly from the water processor product water storage tanks. This paper will document results encountered and evaluated thus far in the life testing program.

Advanced space suit portable life support systems (PLSS) require high performance fans for the breathing gas ventilation system. AlliedSignal has developed a high speed air bearing fan for this application. This work addresses the development of an advanced electronic controller to drive this fan. Advances in space suit technology required an improved fan controller. The architecture of the controller was modified to enhance performance and facilitate testing in a space environment. These modifications were both physical and functional. To reduce the size of the controller, electrical, electronic and electromechanical (EEE) components were divided into two circuit cards, the housing was redesigned, test points and control knobs were removed, and a higher grade of EEE components were used in the development of the controller. These modifications improved the functional characteristics of the controller.

The Lunar-Mars Life Support Test Project (LMLSTP) Phase III test examined the use of biological and physicochemical life support technologies for the recovery of potable water from waste water, the regeneration of breathable air, and the maintenance of a shirt-sleeve environment for a crew of four persons for 91 days. This represents the longest duration ground-test of life support systems with humans performed in the United States. This paper will describe the test from the inside viewpoint, concentrating on three major areas: maintenance and repair of life support elements, the scientific projects performed primarily in support of the International Space Station, and numerous activities in the areas of public affairs and education outreach.

The current dual-membrane gas trap is designed to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Design goals are to meet or exceed the current requirements to (1) include greater operating ranges and conditions, (2) eliminate reliance on the current hydrophilic tube fabrication process, and (3) increase operational life and tolerance to particulate and microbial growth fouling.

A dual-membrane gas trap is currently used to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the NCG. The inner hydrophobic fiber allows the trapped NCG to pass through and vent to the ambient atmosphere in the cabin. The purpose of the gas trap is to prevent gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump, and the current gas trap has performed flawlessly in this regard. However, because of actual operational conditions on-orbit, its gas removal performance and operational lifetime have been affected.

Although designed to remove organic contaminants from a variety of wastewater streams, the planned U.S. and present Russian-provided water processing systems on board the International Space Station (ISS) have capacity limits for some of the more common volatile cleaning solvents used for housekeeping purposes. Using large quantities of volatile cleaning solvents during the ground processing and in-flight operational phases of a crewed spacecraft such as the ISS can lead to significant challenges to the water processing systems. To understand the challenges facing the management of water processing capacity, the relationship between cabin atmospheric quality and humidity condensate loading is presented. This relationship is developed as a tool to determine the cabin atmospheric loading that may compromise water processing system performance.

For the past few years an extensive experimental program to understand the fluid dynamics of the Space Shuttle Main Engine hot gas manifold has been in progress at Marshall Space Flight Center (MSFC). This program includes models of the Phase II and II+ manifolds for each of the air and water flow facilities, as well as two different turbine flow paths and two simulated power levels for each manifold. All models are full scale (geometric). The water models are constructed partially of acrylic to allow flow visualization. The intent of this paper is to discuss the concept, including the test objectives, the facilities, and the models, and to summarize the data for an example configuration, including static pressure data, flow visualization, and the solution of a specific flow problem.

Biological wastewater processing has been under investigation by AlliedSignal Aerospace and NASA Johnson Space Center (JSC) for future use in space. Testing at JSC in the Hybrid Regenerative Water Recovery System (HRWRS) in preparation for future closed human testing has been performed. Computer models have been developed to aid in the design of a new four-person immobilized cell bioreactor. The design of the reactor and validation of the computer model is presented. In addition, the total organic carbon (TOC) computer model has been expanded to begin investigation of nitrification. This model is being developed to identify the key parameters of the nitrification process, and to improve the design and operating conditions of nitrifying bioreactors. In addition, the model can be used as a design tool to rapidly predict the effects of changes in operational conditions and reactor design, significantly reducing the number and duration of experiments required.

A series of tests has been conducted at the NASA Marshall Space Flight Center (MSFC) to evaluate the performance of the Space Station Freedom (SSF) water recovery system. Potable and urine reclamation processors were integrated with waste water generation equipment and successfully operated for a total of 144 days. This testing marked the first occasion in which the waste feed sources for previous potable and hygiene loops were combined into a single loop and processed to potable water quality. Reclaimed potable water from the combined waste waters routinely met the SSF water quality specifications. In the last stage of this testing, data was obtained that indicated that the Water Processor (WP) presterilizer may not be required to meet the potable water quality specification.

One of the primary safety concerns for Space Station Freedom pressurized modules is fire. Some Freedom modules are unattended for long periods of time. In other cases, enclosed, pressurized volumes are not open to crew monitoring. As a result, a fire detection system is required to continuously monitor all modules for combustion. This paper briefly reviews the overall design for the Freedom fire detection system, and the design of the two basic types of detectors: smoke and flame. The smoke detectors monitor particulates in small open areas, stand-offs, end-cones, and racks. The flame detectors survey open areas for radiation at wavelengths and intensities characteristic of combustion. Responses from detectors are evaluated by Freedom's data management system to determine the presence of combustion and to recommend appropriate action.

A series of tests has been conducted at the NASA Marshall Space Flight Center (MSFC) to evaluate the performance of a Space Station Freedom (SSF) pre-development water recovery system. Potable, hygiene, and urine reclamation subsystems were integrated with end-use equipment items and successfully operated for a total of 35 days, including 23 days in closed-loop mode with man-in-the-loop. Although several significant subsystem physical anomalies were encountered, reclaimed potable and hygiene water routinely met current SSF water quality specifications. This paper summarizes the test objectives, system design, test activities/protocols, significant results/anomalies, and major lessons learned.

A primary concern in creating a water reclamation system for long-duration manned space flight is the control of microbial contamination which can jeopardize water quality, compromise human health, and degrade constituent materials of the system. The microbial ecology facility in the Analytical and Physical Chemistry Branch of the Materials and Processes Laboratory at NASA's Marshall Space Flight Center (MSFC) is addressing this concern by means of experiments investigating the interaction of bacterial species in the development of a biofilm and their response to the introduction of additional species or to disinfection. Both static and recycling water systems are used. In static experiments, varied sequence and timing of species introduction in binary bacterial biofilms on 316L stainless steel elucidate the mechanisms involved in biofilm formation.

Life Sciences research on Space Station will utilize rats to study the effects of the microgravity environment on mammalian physiology and to develop countermeasures to those effects for the health and safety of the crew. The animals will produce metabolic water which must be reclaimed to minimize logistics support. The condensate from the Research Animal Holding Facility (RAHF) flown on Spacelab Life Sciences-2 (SLS-2) in October 1993 was used as an analog to determine the type and quantity of constituents which the Space Station (SS) water reclamation system will have to process. The most significant organics present in the condensate were 2-propanol, glycerol, ethylene glycol, 1,2-propanediol, acetic acid, acetone, total proteins, urea and caprolactam while the most significant inorganic was ammonia. Microbial isolates included Xanthomonas, Sphingobacterium, Pseudomonas, Penicillium, Aspergillus and Chrysosporium.