Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 159

This bibliography lists 257 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1976

Method for optimal configuration of an ECLSS on the Space Station Freedom

The establishment of a permanently manned Space Station represents a substantial challenge in the design of a life support system, specifically in the need to supply a large crew for missions of extended duration. The Space Station will evolve by time phased modular increments delivered and supplied by the Space Shuttle and other advanced launch systems. With the addition of each subsequent phase or alteration of mission duties, the requirements of the Station may differ from previous phases of development. With the addition of future crews and pressurized volume throughout the lifetime of the Space Station, change-out of individual subsystems may be necessary in order to meet the performance, safety, and reliability levels required from the Environmental Control and Life Support System (ECLSS). The analysis of this system growth demands the capability for advanced, integrated assessment techniques so that the unique mission drivers during each phase and mission scenario may be identified and evaluated. In order to determine the impacts of the interdependency between the ECLSS, the crew, the various user experiments, and the other distributed systems, consideration must be given to all Space Station resources and requirements during the initial and subsequent evolution phase. Therefore, it is necessary for analysis efforts to study the long term effects of established designs. These studies must quantify the optimal degree of loop closure within the capabilities of existing and future technologies including any resulting maintenance and logistics requirements. In addition, the necessity for subsystem retrofit during the lifetime of the Station must be examined. The source of system requirements due to long term exposure to the microgravity environment is illustrated, the criticality of the ECLSS functions is reviewed, and a method is described to develop an optimal design during each configuration based on the cross-consumption of Station resources. A comparison utilizing this procedure is discussed

Influence of illuviated clays and soil cements on hydraulic conductivity in sedimentary saprolite

A stepped pit was excavated to a depth of 3.4 meters In soil and saprolite formed from the Maryville Limestone (Middle Cambrian) at a site near Oak Ridge, TN. Field-scale measurements of hydraulic conductivity, Ksat and K(Ψ), and thin-section microscopy were used to test the hypothesis that illuviated clays and Fe/Mn cements are common occurrences in sedimentary saprolite and are responsible for the formation of a low K zone (depth \u3c0.5-1.5 m) typically found in these materials. Results show that the onset of deposition of pedogenic clay and Fe/Mn oxides at about 60 to 100 cm depth corresponds to a two-orders-of-magnitude reduction in saturated hydraulic conductivity. Observations also indicate that accumulations of pedogenic clays and Fe/Mn oxides can occur to depths of at least 3 m, and that the relative amount of infilling in the deep saprolite does not correlate well to variations in hydraulic conductivity. The influence of lithology becomes increasingly important as one proceeds deeper into the section, because the frequency and nature (fractures vs. root holes) of the macropores varies according to lithology. Limestone-derived saprolite tends to have more frequent root holes and a higher abundance of pedogenic clay and Fe/Mn oxide infilling than shale/siltstone saprolite. However, variations in hydraulic conductivity tend to cross lithologic boundaries, indicating that variations in K depend on the interaction of a variety of factors, and suggesting that very complex flow systems are likely to develop in the saprolite. These findings further our understanding of groundwater flow through the unsaturated zone in sedimentary saprolite, and have implications for agriculture, soil drainage, aquifer recharge, and contaminant migration in these materials

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 204

This bibliography lists 140 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1980

Nutrition During Long Flight

The nutrition of astronautics during long flights is discussed, especially with respect to the changes brought about in the body by the condition of weightlessness

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 309)

This bibliography lists 136 reports, articles and other documents introduced into the NASA scientific and technical information system in February, 1988

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 308)

This bibliography lists 175 reports, articles, and other documents introduced into the NASA scientific and technical information system in February, 1988

The NASA firefighter's breathing system program

The research is reported in the development of a firefighter's breathing system (FBS) to satisfy the operational requirements of fire departments while remaining within their cost constraints. System definition for the FBS is discussed, and the program status is reported. It is concluded that the most difficult problem in the FBS Program is the achievement of widespread fire department acceptance of the system

Microbial biofilm studies of the environmental control and life support system water recovery test for Space Station Freedom

NASA is developing a water recovery system (WRS) for Space Station Freedom to reclaim human waste water for reuse by astronauts as hygiene or potable water. A water recovery test (WRT) currently in progress investigates the performance of a prototype of the WRS. Analysis of biofilm accumulation, the potential for microbially influenced corrosion (MIC) in the WRT, and studies of iodine disinfection of biofilm are reported. Analysis of WRT components indicated the presence of organic deposits and biofilms in selected tubing. Water samples for the WRT contained acid-producing and sulfate-reducing organisms implicated in corrosion processes. Corrosion of an aluminum alloy was accelerated in the presence of these water samples; however, stainless steel corrosion rates were not accelerated. Biofilm iodine sensitivity tests using an experimental laboratory scale recycled water system containing a microbial check valve (MCV) demonstrated that an iodine concentration of 1 to 2 mg/L was ineffective in eliminating microbial biofilm. For complete disinfection, an initial concentration of 16 mg/L was required, which was gradually reduced by the MCV over 4 to 8 hours to 1 to 2 mg/L. This treatment may be useful in controlling biofilm formation

Generalized environmental control and life support system computer program (G189A) configuration control, phase 2

A method for updating and maintaining the G189A program library and documentation for all program users is provided. The effort also involves: (1) providing instruction and recommendations for the use and application of the program, (2) developing new subroutines and the logic required for new simulations, (3) supporting special analyses required by CSD, and (4) conduct studies to define and understand the interaction of the shuttle ECLSS and propose payload ECLSS and ECS designs