Critical care medicine in space.
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Aerospace Medicine↗
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Results for “NASA Discipline Life Support Systems”
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Detection of biogenic CO production above vascular cell cultures using a near-room-temperature QC-DFB laser.
We report the first application of pulsed, near-room-temperature quantum cascade laser technology to the continuous detection of biogenic CO production rates above viable cultures of vascular smooth muscle cells. A computer-controlled sequence of measurements over a 9-h period was obtained, resulting in a minimum detectable CO production of 20 ppb in a 1-m optical path above a standard cell-culture flask. Data-processing procedures for real-time monitoring of both biogenic and ambient atmospheric CO concentrations are described.
Air Conditioning↗
Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors.
Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.
Air Conditioning↗
Automated fault-management in a simulated spaceflight micro-world.
BACKGROUND: As human spaceflight missions extend in duration and distance from Earth, a self-sufficient crew will bear far greater onboard responsibility and authority for mission success. This will increase the need for automated fault management (FM). Human factors issues in the use of such systems include maintenance of cognitive skill, situational awareness (SA), trust in automation, and workload. This study examine the human performance consequences of operator use of intelligent FM support in interaction with an autonomous, space-related, atmospheric control system. METHODS: An expert system representing a model-base reasoning agent supported operators at a low level of automation (LOA) by a computerized fault finding guide, at a medium LOA by an automated diagnosis and recovery advisory, and at a high LOA by automate diagnosis and recovery implementation, subject to operator approval or veto. Ten percent of the experimental trials involved complete failure of FM support. RESULTS: Benefits of automation were reflected in more accurate diagnoses, shorter fault identification time, and reduced subjective operator workload. Unexpectedly, fault identification times deteriorated more at the medium than at the high LOA during automation failure. Analyses of information sampling behavior showed that offloading operators from recovery implementation during reliable automation enabled operators at high LOA to engage in fault assessment activities CONCLUSIONS: The potential threat to SA imposed by high-level automation, in which decision advisories are automatically generated, need not inevitably be counteracted by choosing a lower LOA. Instead, freeing operator cognitive resources by automatic implementation of recover plans at a higher LOA can promote better fault comprehension, so long as the automation interface is designed to support efficient information sampling.
Adult↗
Development of the EMCS hardware for multigenerational growth of Drosophila melanogaster in space.
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Animals↗
Effects of regenerator geometry on pulse tube refrigerator performance.
This paper gives results of the cooling performance of a double-inlet pulse tube refrigerator using various regenerators. The same pulse tube was used for all the experiments and measured 4.76 mm in diameter and 46.2 mm in length. A commercial linear compressor with a swept volume of 4 cm3 was used in these experiments. The operating conditions were held constant at a mean pressure of 2.0 MPa and a frequency of 54 Hz. Using finite difference software called REGEN3.1, developed at NIST, and recent experiment results, we optimized a series of regenerators based on dimensions, materials and screen packing. The values used for calculating the thermal conduction through stacked screens by REGEN3.1 were based on recent experimental results from NIST. The regenerator tubes were designed using 316 stainless steel and titanium materials. The regenerator matrices investigated were 400-mesh and 500-mesh stainless steel screen. The valve settings for both orifices were adjusted to minimize the no-load temperature for all regenerators. A cooling capacity curve from 0 to 3 W was also determined. The performance of the pulse tube refrigerator using the different regenerators is discussed. The experimental results from the various regenerators are evaluated and compared with their corresponding numerically calculated coefficient of performance (COP) and regenerator design as determined by REGEN3.1.
Equipment Design↗
Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring.
An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.
Air Conditioning↗
Space Station Biological Research Project.
To meet NASA's objective of using the unique aspects of the space environment to expand fundamental knowledge in the biological sciences, the Space Station Biological Research Project at Ames Research Center is developing, or providing oversight, for two major suites of hardware which will be installed on the International Space Station (ISS). The first, the Gravitational Biology Facility, consists of Habitats to support plants, rodents, cells, aquatic specimens, avian and reptilian eggs, and insects and the Habitat Holding Rack in which to house them at microgravity; the second, the Centrifuge Facility, consists of a 2.5 m diameter centrifuge that will provide acceleration levels between 0.01 g and 2.0 g and a Life Sciences Glovebox. These two facilities will support the conduct of experiments to: 1) investigate the effect of microgravity on living systems; 2) what level of gravity is required to maintain normal form and function, and 3) study the use of artificial gravity as a countermeasure to the deleterious effects of microgravity observed in the crew. Upon completion, the ISS will have three complementary laboratory modules provided by NASA, the European Space Agency and the Japanese space agency, NASDA. Use of all facilities in each of the modules will be available to investigators from participating space agencies. With the advent of the ISS, space-based gravitational biology research will transition from 10-16 day short-duration Space Shuttle flights to 90-day-or-longer ISS increments.
Aerospace Medicine↗
Sustaining humans in space.
One goal of NASA's Ames Research Center is to extend the presence of humans in space. Biomedical research, human performance, and life-support systems form the core of the Ames program. Major questions highlight how the effects of microgravity on living systems are modified by exercise, artificial gravity, autogenic feedback training, and nutrition. Bioengineering and life science studies include humans, animals, and plants. Ames investigators collaborate extensively with outside university and commercial scientists, both within the United States and internationally.
Bone Density↗
Monitoring space shuttle air quality using the Jet Propulsion Laboratory electronic nose.
A miniature electronic nose (ENose) has been designed and built at the Jet Propulsion Laboratory (JPL), Pasadena, CA, and was designed to detect, identify, and quantify ten common contaminants and relative humidity changes. The sensing array includes 32 sensing films made from polymer carbon-black composites. Event identification and quantification were done using the Levenberg-Marquart nonlinear least squares method. After successful ground training, this ENose was used in a demonstration experiment aboard STS-95 (October-November, 1998), in which the ENose was operated continuously for six days and recorded the sensors' response to the air in the mid-deck. Air samples were collected daily and analyzed independently after the flight. Changes in shuttle-cabin humidity were detected and quantified by the JPL ENose; neither the ENose nor the air samples detected any of the contaminants on the target list. The device is microgravity insensitive.
Air Conditioning↗
Life sciences issues affecting space exploration.
The U.S. space program is undertaking a serious examination of new initiatives in human space exploration involving permanent colonies on the Moon and an outpost on Mars. Life scientists have major responsibilities to the crew, to assure their health, productivity, and safety throughout the mission and the postflight rehabilitation period; to the mission, to provide a productive working environment; and to the scientific community, to advance knowledge and understanding of human adaptation to the space environment. Critical areas essential to the support of human exploration include protection from the radiation hazards of the space environment, reduced gravity countermeasures, artificial gravity, medical care, life support systems, and behavior, performance, and human factors in an extraterrestrial environment. Developing solutions to these concerns is at the heart of the NASA Life Sciences ground-based and flight research programs. Facilities analogous to planetary outposts are being considered in Antarctica and other remote settings. Closed ecological life support systems will be tested on Earth and Space Station. For short-duration simulations and tests, the Space Shuttle and Spacelab will be used. Space Station Freedom will provide the essential scientific and technological research in areas that require long exposures to reduced gravity conditions. In preparation for Mars missions, research on the Moon will be vital. As the challenges of sustaining humans on space are resolved, advances in fundamental science, medicine and technology will follow.
Adaptation, Physiological↗
Crucial factor: human. Safely extending the human presence in space.
The concept of advanced manned space missions has captured the interest and imagination of spacefaring nations. However, the physiological and psychological effects of space flight increase in magnitude and significance in the 'extended time-in-space' context. The unencumbered weightless condition enjoyed during short flights might compromise crew productivity upon return to a gravity field and extremely effective countermeasures may be essential. Missions remote from Earth require careful consideration of the medical facilities, psychological support and life support needed. The author discusses pressing issues that must be resolved before the visions of bolder human missions can be realistically fulfilled.
Adaptation, Physiological↗
Microbial colonization of a closed growth chamber during hydroponic cultivation of lettuce.
The goal of this study was to characterize sessile and planktonic microbiota that developed during two successive hydroponic cultures of lettuce in a closed chamber system. Coupons of polyvinyl chloride (PVC) placed in the nutrient solution lines were removed periodically, as were samples of the nutrient solutions and condensate from the air-handling system. The bacteria and fungi present on the coupons and in fluid samples were enumerated by direct plate counts. Disinfecting the hydroponic system with 0.1% hypochlorite and 0.1 N nitric acid reduced the bacterial densities in biofilm samples from 1 x 10(7) CFU/10 cm2 to 1 x 10(1) CFU/10 cm2 and eliminated culturable fungi; Staphylococcus sp., Pseudomonas sp., and Micrococcus sp. survived this procedure. Bacterial and fungal concentrations in all samples returned to predisinfection levels after 2 days of plant growth. Pseudomonas and Acremonium predominated both before and after disinfection. Fungal concentrations never exceeded 7 x 10(2) CFU/10 cm2. The coupon microbiota differed from that of the rhizoplane at harvest. Overall, the greatest numbers of species were found on the rhizoplane samples collected during the second crop. The microbial community changed little during individual crops or between successive crops. Diversity indices remained relatively constant for all samples.
Bacteria↗
Testing a Mars science outpost in the Antarctic dry valleys.
Field research conducted in the Antarctic has been providing insights about the nature of Mars in the science disciplines of exobiology and geology. Located in the McMurdo Dry Valleys of southern Victoria Land (160 degrees and 164 degrees E longitude and 76 degrees 30' and 78 degrees 30' S latitude), research outposts are inhabited by teams of 4-6 scientists. We propose that the design of these outposts be expanded to enable meaningful tests of many of the systems that will be needed for the successful conduct of exploration activities on Mars. Although there are some important differences between the environment in the Antarctic dry valleys and on Mars, the many similarities and particularly the field science activities, make the dry valleys a useful terrestrial analog to conditions on Mars. Three areas have been identified for testing at a small science outpost in the dry valleys; 1) studying human factors and physiology in an isolated environment; 2) testing emerging technologies (e.g., innovative power management systems, advanced life support facilities including partial bioregenerative life support systems for water recycling and food growth, telerobotics, etc.); and 3) conducting basic scientific research that will enhance our understanding of Mars while contributing to the planning for human exploration. We suggest that an important early result of a Mars habitat program will be the experience gained by interfacing humans and their supporting technology in a remote and stressful environment.
Antarctic Regions↗
Numerical simulation of iodine speciation in relation to water disinfection aboard manned spacecraft I. Equilibria.
Elemental iodine (I2) is currently used as the drinking water disinfectant aboard the Shuttle Orbiter and will also be incorporated into the water recovery and distribution system for the International Space Station Alpha. Controlled release of I2 is achieved using the Microbial Check Valve (MCV), a flow-through device containing an iodinated polymer which imparts a bacteriostatic residual concentration of approximately 2mg/L to the aqueous stream. During regeneration of MCV canisters, I2 concentrations of approximately 300 mg/L are used. Dissolved iodine undergoes a series of hydrolytic disproportionation and related reactions which result in the formation of an array of inorganic species including: I-, I3-, HOI, OI-, IO3-, HIO3, I2OH-, I2O(-2), and H2OI+. Numerical estimation of the steady-state distribution of inorganic iodine containing species in pure water at 25 degrees C has been achieved by simultaneous solution of the multiple equilibrium expressions as a function of pH. The results are reported herein.
Disinfection↗
Controlled ecological life-support system. Use of plants for human life-support in space.
Scientists and engineers within NASA are conducting research which will lead to development of advanced life-support systems that utilize higher plants in a unique approach to solving long-term life-support problems in space. This biological solution to life-support, Controlled Ecological Life-Support System (CELSS), is a complex, extensively controlled, bioengineered system that relies on plants to provide the principal elements from gas exchange and food production to potable water reclamation. Research at John F. Kennedy Space Center (KSC) is proceeding with a comprehensive investigation of the individual parts of the CELSS system at a one-person scale in an approach called the Breadboard Project. Concurrently a relatively new NASA sponsored research effort is investigating plant growth and metabolism in microgravity, innovative hydroponic nutrient delivery systems, and use of highly efficient light emitting diodes for artificial plant illumination.
Aerospace Medicine↗
Accretion of Moon and Earth and the emergence of life.
The discrepancy between the impact records on the Earth and Moon in the time period, 4.0-3.5 Ga calls for a re-evaluation of the cause and localization of the late lunar bombardment. As one possible explanation, we propose that the time coverage in the ancient rock record is sufficiently fragmentary, so that the effects of giant, sterilizing impacts throughout the inner solar system, caused by marauding asteroids, could have escaped detection in terrestrial and Martian records. Alternatively, the lunar impact record may reflect collisions of the receding Moon with a series of small, original satellites of the Earth and their debris in the time period about 4.0-3.5 Ga. The effects on Earth of such encounters could have been comparatively small. The location of these tellurian moonlets has been estimated to have been in the region around 40 Earth radii. Calculations presented here, indicate that this is the region that the Moon would traverse at 4.0-3.5 Ga, when the heavy and declining lunar bombardment took place. The ultimate time limit for the emergence of life on Earth is determined by the effects of planetary accretion--existing models offer a variety of scenarios, ranging from low average surface temperature at slow accretion of the mantle, to complete melting of the planet followed by protracted cooling. The choice of accretion model affects the habitability of the planet by dictating the early evolution of the atmosphere and hydrosphere. Further exploration of the sedimentary record on Earth and Mars, and of the chemical composition of impact-generated ejecta on the Moon, may determine the choice between the different interpretations of the late lunar bombardment and cast additional light on the time and conditions for the emergence of life.
Earth, Planet↗
Shoot growth in aseptically cultivated daylily and haplopappus plantlets after a 5-day spaceflight.
Plantlets of daylily (Hemerocallis cv. Autumn Blaze) regenerated from cell suspensions, and 4 clonal populations of Haplopappus gracilis were aseptically cultivated aboard the Shuttle "Discovery" during a 5-day mission within NASA's Plant Growth Unit (PGU) apparatus. Daylily was selected as a representative herbaceous perennial monocotyledon and the haplopappus clones represented an annual dicotyledon. The latter included 4 strains with different physiological and morphological characteristics: two aseptic seedling clones (each generated from a single seedling) and two tissue culture-derived lines. Mean daily growth rates for the primary shoots of all plantlets averaged 4.13 mm day-1 (SD = 2.20) for the flight experiment and 4.68 mm day-1 (SD = 2.59) for the ground control. Comparable growth rates calculated by summing both the primary and secondary shoots for all plantlets were 5.94 mm day-1 (SD = 2.89) for the flight experiment and 6.38 mm day-1 (SD = 3.71) for the control. Statistically significant differences existed between: (1) flight vs control primary shoot growth (the controls growing more than plantlets subjected to spaceflight conditions), (2) the different populations (the daylily gaining more shoot material than any of the haplopappus populations and the haplopappus seedling clones outperforming the tissue culture-derived haplopappus lines), and (3) the individual Plant Growth Chambers contained within the PGU. The data suggest that some spaceflight-associated factor(s) increased the tendency for primary shoot apices to degrade or senesce, resulting in the release of apical dominance and permitting the emergence of axillary branches, which subsequently partially compensated for the reduced primary axis growth. In addition to spaceflight-associated factors, the physiologically diverse nature of the experimental material as well as environmental heterogeneities within the culture apparatus contributed to the variation in growth results. The findings could explain some discrepancies reported from various plant culture experiments conducted in space.
Asepsis↗