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Viewing 1 to 21 of 21
1992-07-01
Technical Paper
921410
Hector D. Garcia, Thomas F. Limero, John T. James
Since the early years of the manned space program, NASA has developed and used exposure limits called Spacecraft Maximum Allowable Concentrations (SMACs) to help protect astronauts from airborne toxicants. Most of these SMACS are based on an exposure duration of 7 days, since this is the duration of a “typical” mission. A set of “contingency SMACs” is also being developed for scenarios involving brief (1-hour or 24- hour) exposures to relatively high levels of airborne toxicants from event-related “contingency” releases of contaminants. The emergency nature of contingency exposures dictates the use of different criteria for setting exposure limits. The NASA JSC Toxicology Group recently began a program to document the rationales used to set new SMACs and plans to review the older, 7-day SMACs. In cooperation with the National Research Council's Committee on Toxicology, a standard procedure has been developed for researching, setting, and documenting SMAC values.
1992-07-01
Technical Paper
921214
Joyce A. Skweres, Virginia J. Bassinger, and S. K. Mishra, Duane L. Pierson
Abstract Reference cultures of 16 microorganisms obtained from the American Type Culture Collection and four clinical isolates were used in standardized solutions to inoculate 60 cards for each test strain. A set of three ID and three susceptibility cards was processed in the Vitek AutoMicrobic System (AMS) immediately after inoculation. The remaining cards were refrigerated at 4°C, and sets of six cards were removed and processed periodically for up to 17 days. The preinoculated AMS cards were evaluated for microorganism identification, percent probability of correct identification, length of time required for final result, individual substrate reactions, and antibiotic minimal inhibitory concentration (MIC) values. Results indicate that 11 of the 20 microbes tested withstood refrigerated storage up to 17 days without detectable changes in delineating characteristics. MIC results appear variable, but certain antibiotics proved to be more stable than others.
1992-07-01
Technical Paper
921213
Louis A. Cioletti, S. K. Mishra, Duane L. Pierson
Abstract With the restructure and funding changes for Space Station Freedom, the Environmental Health System (EHS)/Microbiology Subsystem revised its scheduling and operational requirements for component hardware. The function of the Microbiology Subsystem is to monitor the environmental quality of air, water, and internal surfaces and, in part, crew health on board Space Station. Its critical role shall be the identification of microbial contaminants in the environment that may cause system degradation, produce unsanitary or pathogenic conditions, or reduce crew and mission effectiveness. EHS/Microbiology operations and equipment shall be introduced in concert with a phased assembly sequence, from Man Tended Capability (MTC) through Permanently Manned Capability (PMC). Effective Microbiology operations and subsystem components will assure a safe, habitable, and useful spacecraft environment for life sciences research and long-term manned exploration.
1992-07-01
Technical Paper
921268
Paul D. Mudgett, John R. Schultz, Richard L. Sauer
Until 1989, ion chromatography (IC) was the baseline technology selected for the Specific Ion Analyzer, an in-flight inorganic water quality monitor being designed for Space Station Freedom. Recent developments in capillary electrophoresis (CE) may offer significant savings of consumables, power consumption, and weight/volume allocation, relative to IC technology. A thorough evaluation of CE's analytical capability, however, is necessary before one of the two techniques is chosen. Unfortunately, analytical methods currently available for inorganic CE are unproven for NASA's target list of anions and cations. Thus, CE electrolyte chemistry and methods to measure the target contaminants must be first identified and optimized. This paper reports the status of a study to evaluate CE's capability with regard to inorganic and carboxylate anions, alkali and alkaline earth cations, and transition metal cations.
1991-07-01
Technical Paper
911334
Karen L. Mathes, JoAnna Wood
Shuttle crewmembers must frequently alter sleep/wake schedules to accommodate launch and mission timelines. These “alterations” tend to maximize sleep disruption and fatigue leading to a decreased operational “safety margin” during inflight operations. Changes in normal sleep/wake cycles have been shown to disrupt physiological circadian rhythm causing fatigue, decreased alertness, increased irritability, altered judgement, and increased vulnerability to performance decrements.1 To minimize the impact of schedule shifts, and maximize sleep and physiological adaptation, the NASA operational environment has implemented a program to address these complex issues. The program plan “operationalizes” the experimental protocol used by Czeisler et al. (1990), which involves timed exposure to bright light during the targeted activity period and complete darkness during the targeted sleep period to rapidly shift crewmembers.
1995-07-01
Technical Paper
951614
Cheryl W. Armstrong, Scott C. Simmons, Kyle L. Rhorer
NASA flight surgeons have routinely relied on telemedicine to augment inflight medical care since the Gemini program. The current telemedicine capability aboard the Space Shuttle is limited to two-way voice communication, one-way video, and telemetry of ECG and spacecraft parameters. This capability has been sufficient to manage the routine minor medical problems that have occurred in-flight, but long-duration Space Shuttle and International Space Station missions are likely to be accompanied by more serious medical contingencies. In the event of emergent crew health problems, NASA flight surgeons will require an improved capability to provide a rapid, accurate assessment of an ill or injured crewmember. Onboard systems will supply flight surgeons and medical specialty consultants with real-time voice communication, medical video, and data.
1994-06-01
Technical Paper
941391
Paul D. Mudgett, David T. Flanagan, John R. Schultz, Richard L. Sauer
Iodine depletion in a simulated water storage tank and distribution system was examined to support a larger research program aimed at developing disinfection methods for spacecraft potable water systems. The main objective of this study was to determine the rate of iodine depletion with respect to the surface area of the stainless steel components contacting iodinated water. Two model configurations were tested. The first, representing a storage and distribution system, consisted of a stainless steel bellows tank, a coil of stainless steel tubing and valves to isolate the components. The second represented segments of a water distribution system and consisted of eight individual lengths of 21-6-9 stainless tubing similar to that used in the Shuttle Orbiter. The tubing has a relatively high and constant surface area to volume ratio (S/V) and the bellows tank a lower and variable S/V.
1994-06-01
Technical Paper
941392
Mark E. Homan, Paul D. Mudgett, John R. Schultz, Richard L. Sauer
The objective of this study was to investigate combining GC/MS and CE methods to allow sub-mg/L levels of organic acids to be determined in various water samples. This study also served as a basis for evaluating these instruments for in-flight spacecraft water-quality monitoring and to help determine the modifications needed to convert terrestrial hardware for use in microgravity environments. This paper reports on current GC/MS and CE method development and data generated from some recent spacecraft-related water samples. Plans for further method development are also discussed.
1995-07-01
Technical Paper
951685
John E. Straub, John R. Schultz, William F. Michalek, Richard L. Sauer
On the International Space Station (ISS), humidity condensate will be collected from the atmosphere and treated by multifiltration to produce potable water for use by the crews. Ground-based development tests have demonstrated that multifiltration beds filled with a series of ion-exchange resins and activated carbons can remove many inorganic and organic contaminants effectively from wastewaters. As a precursor to the use of this technology on the ISS, a demonstration of multifiltration treatment under microgravity conditions was undertaken. On the Space Shuttle, humidity condensate from cabin air is recovered in the atmosphere revitalization system, then stored and periodically vented to space vacuum. A Shuttle Condensate Adsorption Device (SCAD) containing sorbent materials similar to those planned for use on the ISS was developed and flown on STS-68 as a continuation of DSO 317, which was flown initially on STS-45 and STS-47.
1995-07-01
Technical Paper
951683
David W. Koenig, Denetia M. Bell-Robinson, Susan M. Johnson, S. K. Mishra, Richard L. Sauer, Duane L. Pierson
One of the proposed methods for monitoring the microbial quality of the water supply aboard the International Space Station is membrane filtration. We adapted this method for space flight by using an off-the-shelf filter unit developed by Millipore. This sealed unit allows liquid to be filtered through a 0.45 μm cellulose acetate filter that sits atop an absorbent pad to which growth medium is added. We combined a tetrazolium dye with R2A medium to allow microbial colonies to be seen easily, and modified the medium to remain stable over 70 weeks at 25°C. This hardware was assembled and tested in the laboratory and during parabolic flight; a modified version was then flown on STS-66. After the STS-66 mission, a back-up plastic syringe and an all-metal syringe pump were added to the kit, and the hardware was used successfully to evaluate water quality aboard the Russian Mir space station.
1991-07-01
Technical Paper
911369
Bruce A. McKinley, Karen L. Mathes, Scott C. Simmons
: Health of space explorers is a requisite for success of human exploration missions and, potentially, for return of explorers to Earth. Continuous, long term existence and complex, potentially hazardous tasks in space environments will challenge health of explorers. Immediate return to Earth will not be possible. Health care systems are being designed to address these concerns, starting from the requirement to maintain health of crew members throughout all mission phases, and the assumption that clinical (medical), preventive, and occupational health care will be necessary in space as on Earth. Systems for medical care, health monitoring and countermeasures, and environmental monitoring and countermeasures are being designed. Basic system definition concepts include an individual crew member, a crew surgeon, remote consultation, equipment, and work area or volume within space habitats that is dedicated for health care.
1996-07-01
Technical Paper
961349
Karen L. Mathes, Beth Stringham Shepherd
A unique rehabilitation team was formed by NASA's Medical Operations Branch (MOB) at Johnson Space Center (JSC) to support the Mir-18 crew, which included the first U.S. astronaut to fly aboard the Mir Space Station. The goal of the rehabilitation team was to safely assist the crew's return to their preflight physical condition by developing and directing a specific rehabilitation program. This paper describes the development and lessons learned regarding rehabilitation of the U.S. astronaut. Since NASA plans a continuous U.S. presence in space through the construction of an International Space Station, lessons learned from this program will be used for improving the program for future returning long-duration crewmembers.
1996-07-01
Technical Paper
961570
Ronald J. Davenport, Richard D. Godec, Viatcheslav A. Petropavlovskikh, Allan J. Mord, John R. Schultz, John E. Straub, Richard L. Sauer
A Total Organic Carbon (TOC) Analyzer has been developed for a Life Sciences Risk Mitigation Flight Experiment to be conducted on Spacehab and the Russian space station, Mir. Initial launch is scheduled for December 1996 (flight STS-81). The analyzer will be tested on the Orbiter in the Spacehab module, including when the Orbiter is docked at the Mir space station. The analyzer is scheduled to be launched again in May 1997 (STS-84) when it will be transferred to Mir. During both flights the analyzer will measure the quality of recycled and ground-supplied potable water on the space station. Samples will be archived for later return to the ground, where they will be analyzed for comparison to in-flight results. Water test samples of known composition, brought up with the analyzer, also will be used to test its performance in microgravity. Ground-based analyses of duplicates of those test samples will be conducted concurrently with the in-flight analyses.
1993-07-01
Technical Paper
932176
Susan V. Muckle, John R. Schultz, Richard L. Sauer
When construction of Space Station Freedom reaches the Permanent Manned Capability stage, plans call for the Water Recovery and Management Subsystem to treat distilled urine, spent hygiene water, and humidity condensate in order to reclaim water of potable quality. The reclamation technologies currently baselined to process these wastewaters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that baselined technologies will be able to effectively remove those compounds that present health risks to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in wastewaters representative of those to be encountered on Space Station. This paper reports the efforts by the Water and Food Analytical Laboratory at the Johnson Space Center to enlarge the database of potential contaminants in humidity condensate.
1992-07-01
Technical Paper
921310
John R. Schultz, David T. Flanagan, Rebekah J. Bruce, Paul D. Mudgett, Sandra E. Carr, Jeffrey A. Rutz, M. Helen Huls, Richard L. Sauer, Duane L. Pierson
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.
1997-07-01
Technical Paper
972290
Stephen T. Vander Ark, Kelly D. Curtis, Albert W. Holland, Christopher F. Flynn
Long duration NASA-Mir program missions, and the planned International Space Station missions, have given impetus for NASA to implement an operational program of psychological preparation, monitoring, and support for its crews. For exploration missions measured in years, the importance of psychological issues increases exponentially beyond what is currently done. Psychologists' role should begin during the vehicle design and crew selection phases. Extensive preflight preparation must focus on individual and team adaptation, and leadership. Factors such as lack of resupply options and communication delays will alter in-flight monitoring and support capabilities, and require a more self-sufficient crew. Involvement in postflight recovery will also be necessry to ensure appropriate reintegration to the family and job.
1997-07-01
Technical Paper
972463
John E. Straub, Susan M. Shimamoto, John R. Schultz, Ronald J. Davenport, Richard L. Sauer
On the International Space Station (ISS), atmospheric humidity condensate and other waste waters will be recycled and treated to produce potable water for use by the crews. Space station requirements include an on-orbit capability for real-time monitoring of key water quality parameters, such as total organic carbon, total inorganic carbon, total carbon, pH, and conductivity, to ensure that crew health is protected for consumption of reclaimed water. The Crew Health Care System for ISS includes a total organic carbon (TOC) analyzer that is currently being designed to meet this requirement. As part of the effort, a spacecraft TOC analyzer was developed to demonstrate the technology in microgravity and mitigate risks associated with its use on station. This analyzer was successfully tested on Shuttle during the STS-81 mission as a risk mitigation experiment. A total of six ground-prepared test samples and two Mir potable water samples were analyzed in flight during the 10-day mission.
1992-07-01
Technical Paper
921315
Jeffrey A. Rutz, Susan V. Muckle, Richard L. Sauer
The STS water system is treated with iodinated water in order to prevent microbial contamination. This water is prepared by adding a concentrated solution of iodine to Ground Service Equipment (GSE) before adding the water in that unit to the spacecraft system. The solution is prepared by dissolving iodine in ethanol to make a tincture stock solution. While this procedure is rapid, the ethanol increases the carbon levels in the STS potable water and may produce unpleasant odors. The resulting high carbon levels preclude the use of total organic carbon measurements as a water quality monitoring tool. The use of triiodide solutions was studied as a substitute for using ethanol solutions. Two dissolution agents, sodium iodide and hydriodic acid, were investigated. Sodium iodide was studied at molar concentration ratios ranging from 1:1 to 2.5:1 sodium iodide to molecular iodine.
1994-06-01
Technical Paper
941388
John R. Schultz, David T. Flanagan, Rebekah J. Bruce, M. Helen Huls, Duane L. Pierson, Richard L. Sauer
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.
1995-07-01
Technical Paper
951615
John R. Pohl, Scott C. Simmons, Terrell M. Guess
As a more permanent human presence in space is established during future missions, crew health issues will require additional attention. Since a physician will not be a part of most crews, the flight surgeons will require more clinical information than can currently be provided to regularly assess crew health status and direct medical treatment. The Telemedicine Instrumentation Pack (TIP) is being designed to enable the Crew Medical Officers (CMO) in space to acquire the necessary medical information for telemedical consultation with the flight surgeons in the Mission Control Center (MCC). To date, two prototypes of the TIP have been developed, with the first being clinically evaluated in a local telemedicine testbed in the Fall of 1994 and the second prototype being recently completed. The current system concept, progress in the development of the system, plans for future development, and the evolution of the system are described.
1997-07-01
Technical Paper
972465
Jeffrey A. Rutz, John R. Schultz, Richard L. Sauer
The Water and Food Analytical Laboratory, at the Johnson Space Center is developing an alternative to EPA Method 625 for analyzing semivolatile organic compounds in water. The current EPA method uses liquid-liquid extraction. The alternative method being developed differs in the sample preparation phase by replacing gravity-dependent liquid-liquid extraction with solid phase extraction (SPE). The ultimate goal is to incorporate the optimum SPE conditions into an automated sample preparation process. The method shows promise with regard to anticipated polar compounds. Fourteen SPE resins and nine elution solvents were compared. For typical analytes encountered by our laboratory, a styrene-divinylbenzene SPE resin and an elution solvent mixture of methylene chloride and ethyl ether were found to give the highest extraction recoveries. A study is in progress to remove water from the extracts before GC/MS analysis.
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