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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.

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.

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 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.

A three-year program to develop a Direct Drive Hall Effect Thruster (D2HET) system began 15 months ago as part of the NASA Advanced Cross-Enterprise Technology Development initiative. The system is expected to reduce significantly the power processing, complexity, weight, and cost over conventional low-voltage systems. The D2HET will employ solar arrays that operate at voltages greater than 300V, and will be an enabling technology for affordable planetary exploration. It will also be a stepping-stone in the production of the next generation of power systems for Earth orbiting satellites. This paper provides a general overview of the program and reports the first year's findings from both theoretical and experimental components of the program.

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.

Spacelab mission thermal integration is one of many activities performed at the NASA Marshall Space Flight Center (MSFC). The Spacelab carrier system has been expanded from the original module/pallet system. Thermodynamics and heat transfer as well as fluid mechanics and fluid dynamics are the support areas discussed here. This support incorporates preflight mission analysis in conjunction with real time mission support and postflight mission analysis. This paper summarizes these activities for the Spacelab carrier complement, citing some of the more challenging thermal control designs for which the Center is and has been responsible. Technology advancements, coupled with the ever increasing needs of the payload community and the desire for flexibility to manifest several distinct payload elements on a single mission, has aided in the evolution of a more diverse Spacelab carrier complement.

Nickel-hydrogen (Ni-H2) technology has only recently been utilized in low earth orbit (LEO) applications. The Hubble Space Telescope (HST) program, over the past five years, played a key role in developing this application. The HST not only became the first reported, nonexperimental program to fly Ni-H2 batteries in a LEO application, but funded numerous, ongoing tests that served to validate this usage. The Marshall Space Flight Center (MSFC) has been testing HST Ni-H2 batteries and cells for over three years. The major tests include a 6-battery system (SBS) test and a single 22-cell battery (FSB) test. The SBS test has been operating for 34 months and completed approximately 15,200 cycles. The performance of the cells and batteries in this test is nominal. Currently, the batteries are operating at an average end-of-charge (EOC) pressure that indicates an average capacity of approximately 79 ampere-hours (Ah).

The Russian space program has maintained crews on long duration space flights nearly continuously over the past two decades. As a result, a strong emphasis has been placed on the development of regenerative life support systems. One of these systems is a urine processor which has been operating on-orbit since 1990. The U. S has also been developing urine processing systems to reclaim water from urine over the past twenty years. This paper will describe the two different technologies used for urine processing for long-term human presence in space and will compare the operating characteristics of the two systems.

The appropriate role of human testing in life support systems design has been a key concern for human spacecraft development. This discussion intensified over the past one and a half years as the International Space Station (ISS) evaluated the risk associated with the baseline program while conducting cost and schedule convergence activities. The activity was carried from the traditional top-level discussion to evaluation of the specific Space Station Life Support concerns associated with human interaction, weighed against cost impacts. This paper details the results of this activity, providing the rationale for the present ISS approach.

The Space Station provides a unique facility for conducting material processing and life science experiments under microgravity conditions. These conditions place special requirements on the U.S. Laboratory for storing and transporting chemicals and process fluids, reclaiming water from selected experiments, treating and storing experiment wastes, and providing vacuum utilities. To meet these needs and provide a safe laboratory environment, the Process Material Management System (PMMS) is being developed. Preliminary design requirements and concepts related to the PMMS are addressed in addition to discussing the MSFC PMMS breadboard test facility and a preliminary plan for validating the overall system design. The system contains a fluid handling subsystem which manages process fluids required by each experiment while a chemical storage facility safely stores potentially hazardous chemicals.

The toxicity test method utilized by The National Aeronautics and Space Administration (NASA) is being modified to create an International Standard. The method, NHB 8060.1 C, Test 7, is utilized to determine the identity and quantity of offgassed products from materials and hardware. This paper focuses on the resolution of technical issues faced during its transition from a US specific document to an International Standard. NASA, the European Space Agency (ESA) and the National Space Development Agency of Japan (NASDA) have been very active in bringing ISO 14624-3 through several revisions to its current form. It is anticipated that the document could be an international standard by the end of 1999, with the full support of NASA, ESA, NASDA, and the other national programs represented in Working Group 1.

On June 25, 1997 a docking mishap of a Progress supply ship caused the Progress vehicle to crash into an array of solar panels and puncture the hull of the Spektr module. The puncture was small enough to allow the crew to seal off the Spektr module and repressurize the rest of the station. The Progress vehicle struck the Spektr module several times and the exact location, size, and number of punctures in the Spektr hull was unknown. Russian cosmonauts donned space suits and went inside the Spektr module to repair some electrical power cables and look for the location of the hull breach, they could not identify the exact location of the hole (or holes). The Spektr module was pressurized with Mir cabin air twice during the STS-86 fly around in an attempt to detect leakage (in the form of ice particles) from the module. Seven particles were observed within a 36 second time span, but tracking the path of the individual particles did not pinpoint a specific leak location.

Vapor Compression Distillation (VCD) is the chosen technology for urine processing aboard the International Space Station (ISS). Development and life testing over the past several years have brought to the forefront problems and solutions for the VCD technology. Testing between 1992 and 1998 has been instrumental in developing estimates of hardware life and reliability. It has also helped improve the hardware design in ways that either correct existing problems or enhance the existing design of the hardware. The testing has increased the confidence in the VCD technology and reduced technical and programmatic risks. This paper summarizes the test results and changes that have been made to the VCD design.

The IATCS coolant has experienced a number of anomalies in the time since the US Lab was first activated on Flight 5A in February 2001. These have included: 1) a decrease in coolant pH, 2) increases in inorganic carbon, 3) a reduction in phosphate concentration, 4) an increase in dissolved nickel and precipitation of nickel salts, and 5) increases in microbial concentration. These anomalies represent some risk to the system, have been implicated in some hardware failures and are suspect in others. The ISS program has conducted extensive investigations of the causes and effects of these anomalies and has developed a comprehensive program to remediate the coolant chemistry of the on-orbit system as well as provide a robust and compatible coolant solution for the hardware yet to be delivered.

The vast array of C-130 applications demand a variety of air conditioning solutions to meet the specific needs of each variant and its user. Existing C-130′s are often reconfigured for special use such as airborne early warning and control (AEW&C), electronic surveillance, or armed reconnaissance, or just upgraded to current flight standards where new equipment is added to the aircraft that significantly increases the heat load on the air conditioning system. These factors dictate the need for high-, middle-, and low-end solutions to deliver the increased cooling capacity required at a price each user can afford. This paper will recap the evolution of the C-130 environmental control system (ECS) to date, summarize current improvement efforts, and suggest future ECS developments.