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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.

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.

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 trade study conducted in 2001 selected a rotary disk separator as the best candidate to meet the requirements for an International Space Station (ISS) Carbon Dioxide Reduction Assembly (CRA). The selected technology must provide micro-gravity gas/liquid separation and pump the liquid from 69 kPa (10 psia) at the gas/liquid interface to 124 kPa (18 psia) at the wastewater bus storage tank. The rotary disk concept, which has pedigree in other systems currently being built for installation on the ISS, failed to achieve the required pumping head within the allotted power. The separator discussed in this paper is a new design that was tested to determine compliance with performance requirements in the CRA. The drum separator and pump (DSP) design is similar to the Oxygen Generator Assembly (OGA) Rotary Separator Accumulator (RSA) in that it has a rotating assembly inside a stationary housing driven by a integral internal motor[1].

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.

A test has been completed at NASA's Marshall Space Flight Center (MSFC) to evaluate the latest 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) with higher fidelity hardware and integration than has been achieved in previous integrated tests. Potable and urine reclamation processors were integrated with waste water generation equipment and successfully operated for a total of 116 days to evaluate the impacts of changes made as a result of the redesign from Space Station Freedom (SSF) to the ISS. This testing marked the first occasion in which the WRM was automated at the system level, allowing for evaluation of the hardware performance under ISS operating conditions. It was also the first time a “flight-like” Process Control Water Quality Monitor (PCWQM) and a WM urinal were tested in an integrated system.

The Water Processor Assembly (WPA) for use on the International Space Station (ISS) includes various technologies for the treatment of waste water. These technologies include filtration, ion exchange, adsorption, catalytic oxidation, and iodination. The WPA hardware implementing portions of these technologies, including the Particulate Filter, Multifiltration Bed, Ion Exchange Bed, and Microbial Check Valve, was recently qualified for chemical performance at the Marshall Space Flight Center. Waste water representing the quality of that produced on the ISS was generated by test subjects and processed by the WPA. Water quality analysis and instrumentation data was acquired throughout the test to monitor hardware performance. This paper documents operation of the test and the assessment of the hardware performance.

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.

Long duration human space missions, as planned in the Vision for Space Exploration, will not be possible without applying unprecedented levels of automation to support the human endeavors. The automated and robotic systems must carry the load of routine “housekeeping” for the new generation of explorers, as well as assist their exploration science and engineering work with new precision. Fortunately, the state of automated and robotic systems is sophisticated and sturdy enough to do this work — but the systems themselves have never been human-rated as all other NASA physical systems used in human space flight have. Our intent in this paper is to provide perspective on requirements and architecture for the interfaces and interactions between human beings and the astonishing array of automated systems; and the approach we believe necessary to create human-rated systems and implement them in the space program.

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).

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.

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 three phase catalytic mathematical model was developed for analysis and optimization of the volatile reactor assembly (VRA) used on International Space Station (ISS) Water Processor. The Langmuir-Hinshelwood Hougen-Watson (L-H) expression was used to describe the surface reaction rate. Small column experiments were used to determine the L-H rate parameters. The test components used in the experiments were acetic acid, acetone, ethanol, 1-propanol, 2-propanol and propionic acid. These compounds are the most prevalent ones found in the influent to the VRA reactor. The VRA model was able to predict performance of small column data and experimental data from the VRA flight experiment.

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.

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 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.

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.