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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Air regenerating and conditioning

Various physicochemical methods of regenerating and conditioning air for spacecraft are described with emphasis on conditions which affect efficiency of the system. Life support systems used in closed, hermetically sealed environments are discussed with references to actual application in the Soviet Soyuz and Voskhod manned spacecraft. Temperature and humidity control, removal of carbon dioxide, oxygen regeneration, and removal of bacteria and viruses are among the factors considered.

Grishayenkov, B. G.↗
NASA NTRS1976

Development of a prototype regenerable carbon dioxide absorber

Design information was obtained for a new, regenerable carbon dioxide control system for extravehicular activity life support systems. Solid potassium carbonate was supported in a thin porous sheet form and fabricated into carbon dioxide absorber units. Carbon dioxide and water in the life support system atmosphere react with the potassium carbonate and form potassium bicarbonate. The bicarbonate easily reverts to the carbonate by heating to 150 deg C. The methods of effectively packing the sorbent material into EVA-sized units and the effects of inlet concentrations, flowrate, and temperature upon performance were investigated. The cycle life of the sorbent upon the repeated thermal regenerations was demonstrated through 90 cycles.

Onischak, M.↗
NASA NTRS1976

A regenerable CO2 and humidity control system for Shuttle

A regenerable CO2 and humidity control system is presently being developed for potential use on Shuttle as an alternate to the baseline Lithium Hydroxide (LiOH) system. The system utilizes a sorbent material (designated 'HS-C') to adsorb CO2 and water vapor from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum. Past development programs concentrated on material development and breadboard system fabrication and testing. The present program calls for the design of a flight prototype system capable of integration into the Shuttle vehicle and the development of major components. This paper will show that a regenerable system utilizing HS-C material trades even with the shuttle LiOH system for the baseline four-man, seven-day mission and offers increased savings up to 448 kg for a seven-man, 30-day mission.

Boehm, A. M.↗
NASA NTRS1977

Development of a prototype regeneration carbon dioxide absorber

A prototype regenerable carbon dioxide absorber was developed to maintain the environmental quality of the portable life support system. The absorber works on the alkali metal carbonate-bicarbonate solid-gas reaction to remove carbon dioxide from the atmosphere. The prototype sorber module was designed, fabricated, and tested at simulated extravehicular activity conditions to arrive at optimum design. The unit maintains sorber outlet concentration below 5 mm Hg. An optimization study was made with respect to heat transfer, temperature control, sorbent utilization, sorber life and regenerability, and final size of the module. Important parameters influencing the capacity of the final absorber unit were identified and recommendations for improvement were made.

Patel, P. S.↗
NASA NTRS1977

Ceramic regenerator systems development program

Ceramic regenerator cores are considered that can be used in passenger car gas turbine engines, Stirling engines, and industrial/truck gas turbine engines. Improved materials and design concepts aimed at reducing or eliminating chemical attack were placed on durability test in Ford 707 industrial gas turbine engines. The results of 19,600 hours of turbine engine durability testing are described. Two materials, aluminum silicate and magnesium aluminum silicate, continue to show promise toward achieving the durability objectives of this program. A regenerator core made from aluminum silicate showed minimal evidence of chemical attack damage after 6935 hours of engine test at 800 C and another showed little distress after 3510 hours at 982 C. Results obtained in ceramic material screening tests, aerothermodynamic performance tests, stress analysis, cost studies, and material specifications are also included.

Cook, J. A.↗
NASA NTRS1978

Ceramic regenerator systems development program

Ceramic regenerator cores are considered that can be used in passenger car gas turbine engines, Stirling engines, and industrial/truck gas turbine engines. Improved materials and design concepts aimed at reducing or eliminating chemical attack were placed on durability tests/in industrial gas turbine engines. A regenerator core made from aluminum silicate shows minimal evidence of chemical attack damage after 7804 hours of engine test at 800 C and another showed little distress after 4983 hours at 982 C. The results obtained in ceramic material screening tests, aerothermodynamic performance tests, stress analysis, cost studies, and material specifications are also included.

Cook, J. A.↗
NASA NTRS1980

Argon/UF6 plasma experiments: UF6 regeneration and product analysis

An experimental and analytical investigation was conducted to aid in developing some of the technology necessary for designing a self-critical fissioning uranium plasma core reactors (PCR). This technology is applicable to gaseous uranium hexafluoride nuclear-pumped laser systems. The principal equipment used included 1.2 MW RF induction heater, a d.c. plasma torch, a uranium tetrafluoride feeder system, and batch-type fluorine/UF6 regeneration systems. Overall objectives were to continue to develop and test materials and handling techniques suitable for use with high-temperature, high-pressure, gaseous UF6; and to continue development of complementary diagnostic instrumentation and measurement techniques to characterize the effluent exhaust gases and residue deposited on the test chamber and exhaust system components. Specific objectives include: a development of a batch-type UF6 regeneration system employing pure high-temperature fluorine; development of a ruggedized time-of-flight mass spectrometer and associated data acquisition system capable of making on-line concentration measurements of the volatile effluent exhaust gas species in a high RF environment and corrosive environment of UF6 and related halide compounds.

Roman, W. C.↗
NASA NTRS1981

Evaluation of ceramic packed-rod regenerator matrices

An extensive evaluation of a modified cryocooler with various regenerator matrices is reported. The matrices examined are 0.015 in. diam. Pb spheres and 0.008, 0.015, and 0.030 in. diam. rods of a 0.2% SnCl2 doped ceramic labelled LS-8A. Specific heat and thermal conductivity data on these rod materials are also reported. The chronic pulverization/dusting problem common to Pb spheres was investigated. During a 1000 hr life test with 0.0008 in. diam. rods there was no degradation of the refrigerator performance, and a subsequent examination of the rods themselves revealed no evidence of breakage or pulverization. The load temperature characteristics for the rod packed regenerators were inferior to that for the Pb spheres, the effect being to shift the Pb spheres load curve up in temperature. This temperature shift was 5.0, 7.4, and 11.6K for the 0.0008, 0.015, and 0.030 in. diam. rods, respectively.

Lawless, W. N.↗
NASA NTRS1981

Unconventional processes for food regeneration in space - An overview

Alternatives to conventional plant agriculture for the regeneration of food during space missions of extended duration are examined. The options considered, which may be used in combination with conventional agriculture, include the production of food from plant wastes, the chemical synthesis of food from carbon dioxide and other simple molecules or the substitution of edible chemicals, and the use of microrganisms for food and oxygen regeneration, with suitable processing. A comparison of solar energy conversion efficiencies is presented for nonphotosynthetic bacteria grown on hydrogen and algal systems photosynthetically, and it is shown that hydrogen bacteria are potentially more attractive than photosynthetic algae using artificial light. Weight-volume requirements for the conventional plant, algae and hydrogen bacteria systems are also compared to demonstrate the advantages of microbial systems.

Stokes, B. O.↗
NASA NTRS1983

Regenerable non-venting thermal control subsystem for extravehicular activity

Extravehicular Mobility Unit heat rejection requirements have been formulated for both Space Shuttle Orbiter and space station regenerable nonventing thermal sink (RNTS) applications, where the former involve nonventing extravehicular activity (EVA) missions and the latter both nonventing and regenerable EVA. The present conceptual study notes that while the exclusive use of thermal storage is suitable for the Space Shuttle mission, space station requirements are best satisfied by a hybrid system which combines thermal storage with radiator and heat pump. The Space Shuttle RNTS thermal control subsystem's thermal storage unit uses water as a phase change medium. It is noted that the same heat storage unit can satisfy the Space Shuttle and space station requirements.

Roebelen, G. J., Jr.↗
NASA NTRS1988

Fatigue failure of regenerator screens in a high frequency Stirling engine

Failure of Stirling Space Power Demonstrator Engine (SPDE) regenerator screens was investigated. After several hours of operation the SPDE was shut down for inspection and on removing the regenator screens, debris of unknown origin was discovered along with considerable cracking of the screens in localized areas. Metallurgical analysis of the debris determined it to be cracked-off-deformed pieces of the 41 micron thickness Type 304 stainless steel wire screen. Scanning electron microscopy of the cracked screens revealed failures occurring at wire crossovers and fatigue striations on the fracture surface of the wires. Thus, the screen failure can be characterized as a fatigue failure of the wires. The crossovers were determined to contain 30 percent reduction in wire thickness and a highly worked microstructure occurring from the manufacturing process of the wire screens. Later it was found that reduction in wire thickness occurred because the screen fabricator had subjected it to a light cold-roll process after weaving. Installation of this screen left a clearance in the regenerator allowing the screens to move. The combined effects of the reduction in wire thickness, stress concentration (caused by screen movement), and highly worked microstructure at the wire crossovers led to the fatigue failure of the screens.

Hull, David R.↗
NASA NTRS1987

Development of a regenerable humidity and CO2 control system for an advanced EMU

A 5-h-regenerable nonventing humidity and CO2 control subsystem (HCCS) technology demonstration unit is being developed for potential use in an Advanced Extravehicular Mobility Unit for Space Station application. The HCCS incorporates a weak-base-anion exchange resin packed in a metal-foam-matrix heat exchanger. This system simultaneously removes CO2 and water vapor, with the resulting exothermic heat of reaction rejected to the heat exchanger. The system has no moving parts, resulting in a highly reliable simple configuration. Regeneration may be accomplished via internal heating and vacuum.

Nalette, Timothy A.↗
NASA NTRS1988

Electrochemically regenerable metabolic CO2 and moisture control system for an advanced EMU application

Regenerable CO2 and moisture removal techniques that reduce expendables and logistics requirements are needed to sustain people undertaking extravehicular activities for the Space Station. NASA has been investigating ways to advance the Electrochemically Regenerable CO2 and Moisture Absorption (ERCA) technology to replace the nonregenerable solid lithium hydroxide absorber for the advanced Portable Life Support System (PLSS). The ERCA technology, due to its use of liquid absorbent, has the ability to effectively satisfy the high metabolic CO2 and moisture removal requirements of PLSS applications. This paper defines the ERCA technology concept and its advantages for the PLSS application, reviews breadboard and subscale testdata and presents the results of design concepts for a prototype Absorber Module of improved performance and the physical characteristics of the projected flight hardware.

Lee, M. C.↗
NASA NTRS1989

Metal oxide regenerable carbon dioxide removal system for an advanced portable life support system

The development of a CO2 removal system for an astronaut portable life support system to meet the EVA requirements for the Space Station is discussed, focusing on the factors important in the selection of the metal oxide absorbent for CO2 removal. Results from laboratory tests on metal oxide absorbent materials are given, including characterization studies and dynamic CO2 uptake and regeneration measurements. The preliminary design of the breadboard system to perform both the absorption and regeneration functions is presented.

Nacheff, Maurena S.↗
NASA NTRS1989

Modeling 2-D jets impinging on Stirling regenerators

The extent to which flow leaving Stirling coolers or heaters in the form of high-velocity jets penetrate the regenerator matrix is visually modeled using a computer program. Two-dimensional laminar jets are shown impinging on regenerator samples of variable permeability ranging from no matrix at all to matrices dense enough to stop the jet dead on. The results lend credibility to a simple tension for flow uniformity as a function of penetration depth.

Gedeon, David↗
NASA NTRS1990

Development of a regenerable metal oxide CO removal system

A regenerable metal oxide carbon dioxide (CO2) removal system was developed to replace the current means of a nonreusable chemical, lithium hydroxide, for removing the metabolic CO2 of an astronaut in a space suit. Testing indicates that a viable low-volume metal oxide concept can be used in the portable life support system for CO2 removal during Space Station extravehicular activity (EVA). A canister of nearly the same volume as that used for the Space Shuttle, containing 0.10 cu ft of silver-oxide-based pellets, was tested; test data analysis indicates that 0.18 cu ft of the metal oxide will result in an 8-hour EVA capability. The testing suggests that the metal oxide technology offers a low-volume approach for a reusable CO2 removal concept applicable for at least 40 EVA missions. The development and testing of the breadboard regeneration package is also described.

Cusick, Robert J.↗
NASA NTRS1991

Sorption Compressor With Rotary Regenerator

Proposed two-stage sorption compressor for cryogenic system features rotary regenerator. At each stage, rotor interacts with stator to provide quadruple regeneration. Contains no valves, and only moving part is rotor, which turns very slowly. Features include less required power and greater reliability.

Jones, Jack A.↗
NASA NTRS1989

In vitro regeneration of Basella alba L

Basella alba L. is a tropical vine used as a vegetable in some Asian and African countries. It has potential as a nontraditional crop for small family farms. A short day plant, it blooms during the fall, provided the temperatures are mild. In the southeastern U.S., the short days of fall are associated with subfreezing temperatures, and plants are killed before blooming. Attempts were made to regenerate the plant using tissue culture techniques. Several trials were conducted with different media, hormones, and explants. It was found that nodal segments on Gamborg medium regenerated shoots. Interaction studies of auxins and cytokinins indicated that its endogeneous auxin content might be high because callus proliferated in almost all treatments and roots initiated even when the medium was not supplemented with an auxin.

Edney, Norris Allen↗