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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Space Algae-2: Preflight Testing for A Long-Duration, Multi-Omics Analysis of Arthrospira Platensis

The cyanobacteria Arthrospira platensis NIES-39, commonly known as spirulina, could provide a fresh supply of nutrients for crew on long-duration spaceflight missions. Spirulina is a readily digestible food that is high in protein with all essential amino acids as well as significant levels of B vitamins, antioxidants, and anti-inflammatory metabolites. Spaceflight has multiple abiotic stressors such as increased ionizing radiation and microgravity, which causes a lack of convective mixing. These environmental conditions may impact productivity, nutritional composition, and in long-duration propagation, spaceflight stress may impact the genetic stability of spirulina cultures. We are developing an International Space Station experiment to continuously culture A. platensis for six months. Multi-omics profiling will be used to monitor for changes in the genome, transcriptome, proteome, and metabolome to determine if A. platensis is a suitable nutritional supplement on long-duration missions. During preflight testing we developed a protocol for inoculated liquid cultures to survive a 10-week storage period prior to photo-incubation. The bioreactor bag, temperature, and lighting conditions that support a 14-day growth cycle between passages were also determined. Media testing identified minimal salts supporting robust growth that can be stored in liquid or dry form. A simple filtration method was developed to dewater cultures and harvest biomass for frozen sample return. We optimized a cryopreservation method to enable return of live cells for isolation of individual A. platensis clones. The concept of operations for Space Algae-2 developed from these test results as well as progress on multi-omics analysis methods will be presented.

Algae↗
NASA NTRSDate not supplied

Space Algae-2: Preflight Testing for A Long-Duration, Multi-Omics Analysis of Arthrospira Platensis

The cyanobacteria Arthrospira platensis NIES-39, commonly known as spirulina, could provide a fresh supply of nutrients for crew on long-duration spaceflight missions. Spirulina is a readily digestible food that is high in protein with all essential amino acids as well as significant levels of B vitamins, antioxidants, and anti-inflammatory metabolites. Spaceflight has multiple abiotic stressors such as increased ionizing radiation and microgravity, which causes a lack of convective mixing. These environmental conditions may impact productivity, nutritional composition, and in long-duration propagation, spaceflight stress may impact the genetic stability of spirulina cultures. We are developing an International Space Station experiment to continuously culture A. platensis for six months. Multi-omics profiling will be used to monitor for changes in the genome, transcriptome, proteome, and metabolome to determine if A. platensis is a suitable nutritional supplement on long-duration missions. During preflight testing we developed a protocol for inoculated liquid cultures to survive a 10-week storage period prior to photo-incubation. The bioreactor bag, temperature, and lighting conditions that support a 14-day growth cycle between passages were also determined. Media testing identified minimal salts supporting robust growth that can be stored in liquid or dry form. A simple filtration method was developed to dewater cultures and harvest biomass for frozen sample return. We optimized a cryopreservation method to enable return of live cells for isolation of individual A. platensis clones. The concept of operations for Space Algae-2 developed from these test results as well as progress on multi-omics analysis methods will be presented.

Algae↗
NASA NTRS1999

Effects of square-wave and simulated natural light-dark cycles on hamster circadian rhythms

Circadian rhythms of activity (Act) and body temperature (Tb) were recorded from male Syrian hamsters under square-wave (LDSq) and simulated natural (LDSN, with dawn and dusk transitions) light-dark cycles. Light intensity and data sampling were under the synchronized control of a laboratory computer. Changes in reactive and predictive onsets and offsets for the circadian rhythms of Act and Tb were examined in both lighting conditions. The reactive Act onset occurred 1.1 h earlier (P < 0.01) in LDSN than in LDSq and had a longer alpha-period (1.7 h; P < 0.05). The reactive Tb onset was 0.7 h earlier (P < 0.01) in LDSN. In LDSN, the predictive Act onset advanced by 0.3 h (P < 0.05), whereas the Tb predictive onset remained the same as in LDSq. The phase angle difference between Act and Tb predictive onsets decreased by 0.9 h (P < 0.05) in LDSN, but the offsets of both measures remained unchanged. In this study, animals exhibited different circadian entrainment characteristics under LDSq and LDSN, suggesting that gradual and abrupt transitions between light and dark may provide different temporal cues.

NASA Discipline Regulatory Physiology↗
NASA NTRS2012

External Surface Changes Observed on the International Space Station (ISS) Through 2012

As the International Space Station (ISS) surpasses 13 years of on-orbit operation, 11 of those years continuously inhabited, external surfaces of the vehicle have shown a wide variety of visible environmental effects. Throughout, the ISS program has maintained a significant effort to routinely document the vehicle external surface condition and to monitor those changes with time. The impacts of micrometeoroids and orbital debris, surface changes from molecular contamination of various sources, and the effects of ultraviolet radiation and atomic oxygen have all been noted. The tremendous size and complexity of the ISS vehicle has yielded a wide variety of observations of interest to the spacecraft materials engineer concerning long-term, low earth orbit (LEO) space environmental effects (SEE). In addition, inadvertent materials substitutions have been identified because of these environmental effects, as well as inadequate contamination control practices likely occurring during hardware manufacture and assembly. Some of the observations from our photography are purely artifacts of the unusual lighting conditions and environments that exist in space. A compilation of ISS on-orbit photography representing all of these aspects is presented, demonstrating the various SEE and their impacts as a function of time in LEO, including interpretations of those effects.

Golden, Johnny L.↗
NASA NTRS2003

Transport of the two natural auxins, indole-3-butyric acid and indole-3-acetic acid, in Arabidopsis

Polar transport of the natural auxin indole-3-acetic acid (IAA) is important in a number of plant developmental processes. However, few studies have investigated the polar transport of other endogenous auxins, such as indole-3-butyric acid (IBA), in Arabidopsis. This study details the similarities and differences between IBA and IAA transport in several tissues of Arabidopsis. In the inflorescence axis, no significant IBA movement was detected, whereas IAA is transported in a basipetal direction from the meristem tip. In young seedlings, both IBA and IAA were transported only in a basipetal direction in the hypocotyl. In roots, both auxins moved in two distinct polarities and in specific tissues. The kinetics of IBA and IAA transport appear similar, with transport rates of 8 to 10 mm per hour. In addition, IBA transport, like IAA transport, is saturable at high concentrations of auxin, suggesting that IBA transport is protein mediated. Interestingly, IAA efflux inhibitors and mutations in genes encoding putative IAA transport proteins reduce IAA transport but do not alter IBA movement, suggesting that different auxin transport protein complexes are likely to mediate IBA and IAA transport. Finally, the physiological effects of IBA and IAA on hypocotyl elongation under several light conditions were examined and analyzed in the context of the differences in IBA and IAA transport. Together, these results present a detailed picture of IBA transport and provide the basis for a better understanding of the transport of these two endogenous auxins.

Non-NASA Center↗
NASA NTRS1992

A field measure of the shade fraction

'Shade' has a technical definition peculiar to linear spectral mixture analysis of imaging spectrometer data: it is the reduction in radiance from a surface due to lighting conditions and geometry, and includes topographic shading described by photometric functions as well as shadowing at all scales. 'Shade' is an important constituent of nearly all remotely sensed images, and is one endmember resolved in spectral mixture analysis, where it is represented as a fraction of the measured radiance and a characteristic spectrum. This spectrum is typically the null vector, provided the data have been corrected for atmospheric and instrument effects: i.e., 'shade' is the radiance from an ideal black surface. In topographic shading, irradiance is reduced - typically in proportion to cos(i), where i (incidence angle) is the angle between the sun and the local surface normal vectors. Therefore, the radiance is lowered by a multiplicative factor. Shadowing occurs when i is greater than 90 deg, or when sunlight is blocked by adjacent high terrain; the only irradiance is down-welling skylight and bounce light from adjacent terrain. In spectral mixture analysis, 'shade' is regarded as an additive term. In this regard, it is an accurate description of the proportion of a scene that consists of ideal shadows ('checkerboard mixing'); however, 'shade' represents the multiplicative cos(i) factor as well, as here it should be interpreted as the proportion of shadow that would darken the scene an equivalent amount. In either case, the 'shade' fraction is lessened by adjacency effects, because the scene has a non-zero reflectivity instead of the ideal black surface generally assumed.

Gillespie, Alan R.↗
NASA NTRS1997

A mathematical model of diurnal variations in human plasma melatonin levels

Studies in animals and humans suggest that the diurnal pattern in plasma melatonin levels is due to the hormone's rates of synthesis, circulatory infusion and clearance, circadian control of synthesis onset and offset, environmental lighting conditions, and error in the melatonin immunoassay. A two-dimensional linear differential equation model of the hormone is formulated and is used to analyze plasma melatonin levels in 18 normal healthy male subjects during a constant routine. Recently developed Bayesian statistical procedures are used to incorporate correctly the magnitude of the immunoassay error into the analysis. The estimated parameters [median (range)] were clearance half-life of 23.67 (14.79-59.93) min, synthesis onset time of 2206 (1940-0029), synthesis offset time of 0621 (0246-0817), and maximum N-acetyltransferase activity of 7.17(2.34-17.93) pmol x l(-1) x min(-1). All were in good agreement with values from previous reports. The difference between synthesis offset time and the phase of the core temperature minimum was 1 h 15 min (-4 h 38 min-2 h 43 min). The correlation between synthesis onset and the dim light melatonin onset was 0.93. Our model provides a more physiologically plausible estimate of the melatonin synthesis onset time than that given by the dim light melatonin onset and the first reliable means of estimating the phase of synthesis offset. Our analysis shows that the circadian and pharmacokinetics parameters of melatonin can be reliably estimated from a single model.

NASA Discipline Number 70-10↗
NASA NTRS1999

Stability, precision, and near-24-hour period of the human circadian pacemaker

Regulation of circadian period in humans was thought to differ from that of other species, with the period of the activity rhythm reported to range from 13 to 65 hours (median 25.2 hours) and the period of the body temperature rhythm reported to average 25 hours in adulthood, and to shorten with age. However, those observations were based on studies of humans exposed to light levels sufficient to confound circadian period estimation. Precise estimation of the periods of the endogenous circadian rhythms of melatonin, core body temperature, and cortisol in healthy young and older individuals living in carefully controlled lighting conditions has now revealed that the intrinsic period of the human circadian pacemaker averages 24.18 hours in both age groups, with a tight distribution consistent with other species. These findings have important implications for understanding the pathophysiology of disrupted sleep in older people.

NASA Discipline Regulatory Physiology↗
NASA NTRS1972

Sensor lighting considerations for earth observatory satellite missions

Facets of sensor lighting conditions for Earth observatory satellite missions are considered. Assuming onboard sensors of a given width viewing perpendicular to the subsatellite ground track along sun-synchronous orbits with various nodes, the ground trace of the ends of the sensor coverage were found, as well as the variation in solar illumination on the ground across the line covered by the sensor during the day for any point along the orbit. The changes with season and variation during the year were also found.

Cooley, J. L.↗
NASA NTRS1974

Skylab short-lived event alert program

During the three manned Skylab missions, the Center for Short-Lived Phenomena (CSLP) reported a total of 39 significant events to the Johnson Space Center (JSC) as part of the Skylab Short-Lived Event Alert Program. The telegraphed daily status reports included the names and locations of the events, the track number and revolution number during which the event could be observed, the time (GMT) to within plus or minus 2 sec when Skylab was closest to the event area, and the light condition (daylight or darkness) at that time and place. The messages sent to JSC during the Skylab 4 mission also included information pertaining to ground-truth studies and observations being conducted on the events. Photographic priorities were assigned for each event.

Citron, R. A.↗
NASA NTRS1975

Tug fleet and ground operations schedules and controls. Volume 2: part 2, addenda

The results of a study to assess the tug safing requirements at postlanding are presented. The study considered the normal (green light) conditions from orbiter landing to completion of preparations for the next launch. Normal tug ground turnaround operations include handling and transportation activities and the performance of inspections, tests, and checkout functions. These activities dictate that hazards to ground personnel, the tug, GSE, facilities, and ecology be reduced to the lowest practical level consistent with program objectives, cost, and schedules. During flight operations, the tug contains energy sources that constitute potential hazards but are required for mission accomplishment. These potential hazards have been reduced to an acceptable level for flight operation by design features and by providing for control of energy sources.

Source record↗
NASA NTRS1977

Geologic investigation of Mercury data and the subsequent mapping and explanation of the quadrangle area H-12

The origin of scraps and ridges mapped in the H-12 region of Mercury are discussed. These features apparently are of non-impact origin and show distinctly non-random patterns of distribution and orientation. These patterns cannot be simply related to selective enhancement of visibility by lighting conditions, global stresses of spin down or interior cooling, or local uplifts or subsidences. Suggestions are made that the origin of these structures may lie outside the region of Mercury photographed or the scarps and ridges may have formed by reactivation of faults or joints bounding pre-existing crystal blocks.

Blasius, K. R.↗
NASA NTRS1978

Modular on-board adaptive imaging

Feature extraction involves the transformation of a raw video image to a more compact representation of the scene in which relevant information about objects of interest is retained. The task of the low-level processor is to extract object outlines and pass the data to the high-level process in a format that facilitates pattern recognition tasks. Due to the immense computational load caused by processing a 256x256 image, even a fast minicomputer requires a few seconds to complete this low-level processing. It is, therefore, necessary to consider hardware implementation of these low-level functions to achieve real-time processing speeds. The considered project had the objective to implement a system in which the continuous feature extraction process is not affected by the dynamic changes in the scene, varying lighting conditions, or object motion relative to the cameras. Due to the high bandwidth (3.5 MHz) and serial nature of the TV data, a pipeline processing scheme was adopted as the overall architecture of this system. Modularity in the system is achieved by designing circuits that are generic within the overall system.

Eskenazi, R.↗
NASA NTRS1979

Near-term hybrid vehicle program, phase 1. Appendix B: Design trade-off studies report. Volume 2: Supplement to design trade-off studies

Results of studies leading to the preliminary design of a hybrid passenger vehicle which is projected to have the maximum potential for reducing petroleum consumption in the near term are presented. Heat engine/electric hybrid vehicle tradeoffs, assessment of battery power source, and weight and cost analysis of key components are among the topics covered. Performance of auxiliary equipment, such as power steering, power brakes, air conditioning, lighting and electrical accessories, heating and ventilation is discussed along with the selection of preferred passenger compartment heating procedure for the hybrid vehicle. Waste heat from the engine, thermal energy storage, and an auxiliary burner are among the approaches considered.

Source record↗
NASA NTRS1979

Electronic heterodyne recording of interference patterns

An electronic heterodyne technique is being investigated for video (i.e., television rate and format) recording of interference patterns. In the heterodyne technique electro-optic modulation is used to introduce a sinusoidal phase shift between the beams of an interferometer. For phase modulation frequencies between 0.1 and 15 MHz an image dissector camera may be used to scan the resulting temporally modulated interference pattern. Heterodyne detection of the camera output is used to selectively record the interference pattern. An advantage of such synchronous recording is that it permits recording of low-contrast fringes in high ambient light conditions. The application of this technique to the recording of holograms is discussed.

Merat, F. L.↗
NASA NTRS1980

Comet Science Working Group report on the Halley Intercept Mission

The Halley Intercept Mission is described and the scientific benefits expected from the program are defined. One characteristic of the mission is the optical navigation and resulting accurate delivery of the spacecraft to a desired point near the nucleus. This accuracy of delivery has two important implications: (1) high probability that the mass spectrometers and other in situ measurement devices will reach the cometary ionosphere and the zone of parent molecules next to the nucleus; (2) high probability that sunlit, high resolution images of Halley's nucleus will be obtained under proper lighting conditions. In addition an observatory phase is included during which high quality images of the tail and coma structure will be obtained at progressively higher spatial resolutions as the spacecraft approaches the comet. Complete measurements of the comet/solar wind interaction can be made around the time of encounter. Specific recommendations are made concerning project implementation and spacecraft requirements.

Source record↗
NASA NTRS1980

To develop behavioral tests of vestibular functioning in the Wistar rat

Two tests of vestibular functioning in the rat were developed. The first test was the water maze. In the water maze the rat does not have the normal proprioceptive feedback from its limbs to help it maintain its orientation, and must rely primarily on the sensory input from its visual and vestibular systems. By altering lighting conditions and visual cues the vestibular functioning without visual cues was assessed. Whether there was visual compensation for some vestibular dysfunction was determined. The second test measured vestibular functioning of the rat's behavior on a parallel swing. In this test the rat's postural adjustments while swinging on the swing with the otoliths being stimulated were assessed. Less success was achieved in developing the parallel swing as a test of vestibular functioning than with the water maze. The major problem was incorrect initial assumptions of what the rat's probable behavior on the parallel swing would be.

Nielson, H. C.↗