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Space flight and related factors such as stress appear to have an adverse effect on astronauts' immune systems. The presence of potentially pathogenic microbes including several genera of fungi reported from spacecraft environment may be a cause of concern in such situations. In order to study the role of such organisms in causing opportunistic or allergic diseases in crewmembers, we have tried to develop an animal model. BALB/c mice were suspended upside down for varying periods of time to induce stress, and their lymphocyte functions were evaluated. These studies indicate that the stress resulted in lowered mitogen induced lymphocyte stimulation as represented by 3H-thymidine uptake. We have also studied the ability of these animals to respond to Aspergillus fumigatus spores. The results of the study clearly demonstrate a definite down-regulation in T-cell proliferation and a higher incidence of infection with A. fumigatus.

Two simulated spacecraft water systems are being used to evaluate the effectiveness of iodine for controlling microbial contamination within such systems. An iodine concentration of about 2.0 mg/L is maintained in one system by passing ultrapure water through an iodinated ion exchange resin. Stainless steel coupons with electropolished and mechanically-polished sides are being used to monitor biofilm formation. Results after three years of operation show a single episode of significant bacterial growth in the iodinated system when the iodine level dropped to 1.9 mg/L. This growth was apparently controlled by replacing the iodinated ion exchange resin, thereby increasing the iodine level. The second batch of resin has remained effective in controlling microbial growth down to an iodine level of 1.0 mg/L. Scanning electron microscopy indicates that the iodine has impeded but may have not completely eliminated the formation of biofilm.

The ability of iodine to maintain microbial water quality in a simulated spacecraft water system is being studied. An iodine level of about 2.0 mg/L is maintained by passing ultrapure influent water through an iodinated ion exchange resin. Six liters are withdrawn daily and the chemical and microbial quality of the water is monitored regularly. Stainless steel coupons used to monitor biofilm formation are being analyzed by culture methods, epifluorescence microscopy, and scanning electron microscopy. Results from the first two years of operation show a single episode of high bacterial colony counts in the iodinated system. This growth was apparently controlled by replacing the iodinated ion exchange resin. Scanning electron microscopy indicates that the iodine has limited but not completely eliminated the formation of biofilm during the first two years of operation.

In 1985, the Man-Systems Division at the Johnson Space Center initiated a program for the development of a whole body shower suitable for operation in a microgravity environment. Supporting this development effort has been a systematic research program focused on four critical aspects of the design (i.e., human factors engineering, biomedical, mechanical, and electrical) and on the interfaces between the whole body shower system and the other systems to be aboard the Space Station (e.g., the water reclamation and air revitalization systems). A series of tests has been conducted to help define the design requirements for the whole body shower. Crew interface research has identified major design parameters related to enclosure configurations, consumable quantities, operation timelines, displays and controls, and shower and cleanup protocols.

In-flight contamination control has been an important concern of NASA since the first manned missions. Previous experience has shown that uncontrolled growth of bacteria and fungi can have a detrimental effect on both the health of the crew and the proper operation of flight hardware. It is therefore imperative to develop a safe, effective method of microbial control. Spacecraft application dictates a more stringent set of requirements for biocide selection than is usually necessary for terrestrial situations. Toxicity of the biocide is the driving factor for disinfectant choice in spacecraft. This concern greatly reduces the number and types of chemical agents that can be used as disinfectants. Currently, four biocide candidates (hydrogen peroxide, quaternary ammonium compounds, iodine, glutaraldehyde) are being evaluated as potential surface disinfectants for Space Station Freedom.

We evaluated the ability of a 3% (8800 μM) solution of hydrogen peroxide to kill 12 strains of bacteria and 12 strains of fungi. A 1:4 dilution of 3% H2O2, equivalent to 1100 μM, was lethal to all the tested strains. If the situation calls for a nonaggressive disinfectant without residue or toxic aftereffects, 3% H2O2 seems an ideal choice.

Controlling microbial growth and biofilm formation in spacecraft water-distribution systems is necessary to protect the health of the crew. Methods to decontaminate the water system in flight may be needed to support long-term missions. We evaluated the ability of iodine and ozone to kill attached bacteria and remove biofilms formed on stainless steel coupons. The biofilms were developed by placing the coupons in a manifold attached to the effluent line of a simulated spacecraft water-distribution system. After biofilms were established, the coupons were removed and placed in a treatment manifold in a separate water treatment system where they were exposed to the chemical treatments for various periods. Disinfection efficiency over time was measured by counting the bacteria that could be recovered from the coupons using a sonication and plate count technique. Scanning electron microscopy was also used to determine whether the treatments actually removed the biofilm.

The active control of problematic microbial populations aboard spacecraft, and within future lunar and planetary habitats is a fundamental Advanced Life Support (ALS) requirement to ensure the long-term protection of crewmembers from infectious disease, and to shield materials and equipment from biofouling and biodegradation. The development of effective antimicrobial coatings and materials is an important first step towards achieving this goal and was the focus of our research. A variety of materials were coated with antibacterial and antifungal agents using covalent linkages. Substrates included both granular media and materials of construction. Granular media may be employed to reduce the number of viable microorganisms within flowing aqueous streams, to inhibit the colonization and formation of biofilms within piping, tubing and instrumentation, and to amplify the biocidal activity of low aqueous iodine concentrations.

This paper provides an assessment of functional characteristics needed in the microbial water analysis system being developed for Space Station. Available technology is reviewed with respect to performing microbial monitoring, isolation, or identification functions. An integrated system composed of three different technologies is presented.

The Carbon Dioxide Removal Assembly (CDRA) is a part of the International Space Station (ISS) Environmental Control and Life Support (ECLS) system. The CDRA provides carbon dioxide (CO2) removal from the ISS on-orbit modules. Currently, the CDRA is the secondary removal system on the ISS, with the primary system being the Russian Vozdukh. Within the CDRA are two Desiccant/Adsorbent Beds (DAB), which perform the carbon dioxide removal function. The DAB adsorbent containment approach required improvements with respect to adsorbent containment. These improvements were implemented through a redesign program and have been implemented on units on the ground and returning from orbit. This paper presents a DAB design modification implementation description, a hardware performance comparison between the unmodified and modified DAB configurations, and a description of the modified DAB hardware implementation into the on-orbit CDRA.

The International Space Station (ISS) underwent a dramatic buildup in life support equipment since the delivery and activation of the U.S. Laboratory module in February 2001, followed by the Joint Airlock in July 2001. Since Laboratory activation, several Environmental Control and Life Support (ECLS) equipment failures have occurred. This paper addresses these failures, occurring through February 2002, and, where known, the root causes, with particular emphasis on probable micro-gravity causes are highlighted. Impact to overall ISS operations and proposed or accomplished fixes also are discussed.

The International Space Station continues to build up its life support equipment capability. Several ECLS equipment failures have occurred since Lab activation in February 2001. Major problems occurring between February 2001 and February 2002 were discussed in reference 1. Major problems occurring between February 2002 and February 2003 are discussed in this paper, as are updates from previously ongoing unresolved problems. This paper addresses failures, and root cause, with particular emphasis on likely micro-gravity causes. Impact to overall station operations and proposed and accomplished fixes will also be discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2006 and February 2007 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2007 and February 2008 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station continues to build up and operate its life support equipment. Major events occurring between February 2004 and February 2005 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major events of the last year of ISS operation. Impact to overall station operations is discussed.

The International Space Station (ISS) continues to mature and operate its life support equipment. Major events occurring between February 2005 and February 2006 are discussed in this paper, as are updates from previously ongoing hardware anomalies. This paper addresses the major ISS operation events over the last year. Impact to overall ISS operations is also discussed.

The International Space Station (ISS) United States Laboratory module has been under test for approximately two years in the Space Station Processing Facility (SSPF) at NASA Kennedy Space Center (KSC) preparing for launch. Preparation activities for closing out the Environmental Control and Life Support (ECLS) system have included Closed Hatch testing to verify the capability of the life support equipment to support the crew, final manufacturing steps, and the close-out process itself. These activities were accomplished by an integrated Boeing and NASA team, located at the Johnson Space Center (Houston, Texas), Marshall Space Flight Center (Huntsville, Alabama) and Kennedy Space Center, Florida. On December 13, the Laboratory module hatches were sealed prior to loading into the Shuttle Orbiter payload bay for launch on February 7, 2001.

The International Space Station (ISS) program consists of three distinct phases. Phase 1 consists of the joint Shuttle-Mir missions. Phase 2 establishes the ISS initial research capability with a three person crew permanent presence. Phase 3 completes the assembly, establishing six person crew permanent presence with multiple International Partner (IP) research facilities. Phase 1 is nearing completion, while Phase 2 is in the subsystem delivery and element integration stage. This paper provides a status of the U.S. Environmental Control and Life Support (ECLS) system for Phases 2 and 3 of the ISS program, focusing on updates and changes in the past year.

Weightlessness, cosmic radiation and other space flight related conditions may adversely impact the physiology and immune status of the crew. Since microorganisms will surely be present in space habitats, the effects of space on microbial metabolic and physiologic functions will depend upon environmental conditions, types of organisms, and the duration of the flight. Because humans will conduct long-duration space missions, space microbiology must address the effect of alterations in microbial function during space flight. Even innocuous microorganisms and endogenous flora may become etiologic agents for disease during long missions. The microbial population in the closed environments of spacecraft may also become a source of toxic metabolites or the biodegradation of materials. This paper reviews studies concerning microbial behavior in closed environments, simulated microgravity, and actual space flight.

To mitigate risk to crew health, the microbial surveillance of the quality of potable water sources of the International Space Station (ISS) has been ongoing since before the arrival of the first permanent crew. These water sources have included stored ground-supplied water, water produced by the Shuttle fuel cells during flight, and ISS humidity condensate that is reclaimed and processed. In-flight monitoring was accomplished using a self-contained filtering system designed to allow bacterial growth and enumeration during flight. Upon return to Earth, microbial isolates were identified using 16S ribosomal gene sequencing. While the predominant isolates were common Gram negative bacteria including Ralstonia eutropha, Methylobacterium fujisawaense, and Sphingomonas paucimobilis, opportunistic pathogens such as Stenotrophomonas maltophilia and Pseudomonas aeruginosa were also isolated.