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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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NASA NTRSDate not supplied

The Environmental Data Application for Analysis of Space Telemetry Data

Sensors on the International Space Station (ISS) and multiple spacecraft elsewhere in Earth orbit and in deep space continuously monitor and collect environmental data, transmitting this information back to Earth. These data include ionizing radiation and, on the ISS and spacecrafts, CO2, relative humidity levels, and temperature, and are of great importance to space biology research. Looking ahead to future long duration crewed missions beyond low Earth orbit, the ability to study how factors including CO2 levels, light cycle, temperature modulate the response to ionizing radiation and microgravity is essential. To date, access to these data has been fragmented across space agencies, spacecraft, and databases. To address this issue, NASA’s Open Science Data Repository (OSDR) has developed a user interface for interrogation of telemetry data: the Environmental Data Application (EDA). The EDA provides the capability to visualize telemetry and radiation data collected on the International Space Station and corresponding ground platforms during the Rodent Research missions. Telemetry data includes temperature, relative humidity, and CO2 levels. Radiation data includes galactic cosmic rays, the contribution of the South Atlantic Anomaly, total radiation dose rate, and accumulated radiation dose. The application allows users to view single missions, compare multiple missions, and view and download summary or full data tables. In summary, the EDA provides GUIs for data visualization and exploration, as well as means for data export, making these data FAIR (Findable, Accessible, Interoperable, and Reusable), complementing the biological data contained in OSDR, and providing the space science community with a valuable resource for scientific analyses.

telemetry↗
NASA NTRS1981

Effect of field of view on performing a low altitude maneuvering task

Visual systems with a single window display are often utilized in ground based simulators used to study helicopter flying qualities during visual low altitude maneuvering tasks. The effects of this limited field of view (FOV) on pilot assessments of flying qualities are uncertain. A study was conducted using a variable stability UH-1H helicopter to compare restricted and unrestricted FOV for a range of flying qualities. With the restricted FOV, the pilots reported reduced ground track precision owing to loss of visual contact with the course markers. However, the predictable ground track of the repeated S-turn task with no obstacles made it easy for them to anticipate their maneuvers, and resulted in only a slight degradation of pilot ratings. This degradation was not sensitive to large changes in helicopter flying qualities.

Carico, Dean↗
NASA NTRS2010

Data Visualization and Analysis Tools for the Global Precipitation Measurement (GPM) Validation Network

The Validation Network (VN) prototype for the Global Precipitation Measurement (GPM) Mission compares data from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR) to similar measurements from U.S. and international operational weather radars. This prototype is a major component of the GPM Ground Validation System (GVS). The VN provides a means for the precipitation measurement community to identify and resolve significant discrepancies between the ground radar (GR) observations and similar satellite observations. The VN prototype is based on research results and computer code described by Anagnostou et al. (2001), Bolen and Chandrasekar (2000), and Liao et al. (2001), and has previously been described by Morris, et al. (2007). Morris and Schwaller (2009) describe the PR-GR volume-matching algorithm used to create the VN match-up data set used for the comparisons. This paper describes software tools that have been developed for visualization and statistical analysis of the original and volume matched PR and GR data.

Morris, Kenneth R.↗
NASA NTRS2010

Data Visualization and Analysis Tools for the Global Precipitation Measurement (GPM) Validation Network

The Validation Network (VN) prototype for the Global Precipitation Measurement (GPM) mission compares data from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR) to similar measurements from U.S. and international operational weather radars. This prototype is a major component of the GPM Ground Validation System (GVS). The VN provides a means for the precipitation measurement community to identify and resolve significant discrepancies between the ground radar (GR) observations and similar satellite observations. The VN prototype is based on research results and computer code described by Anagnostou et al. (2001), Bolen and Chandrasekar (2000), and Liao et al. (2001), and has previously been described by Morris, et al. (2007). Morris and Schwaller (2009) describe the PR-GR volume-matching algorithm used to create the VN match-up data set used for the comparisons. This paper describes software tools that have been developed for visualization and statistical analysis of the original and volume matched PR and GR data.

Morris, K. Robert↗
NASA NTRS1972

Interpretation of geographic patterns in simulated orbital television imagery of earth resources

In order to better determine the effects of the television imagery characteristics upon the interpretation of geographic patterns obtainable from orbital television sensors, and in order to better evaluate the influences of alternative sensor system parameters such as changes in orbital altitudes or scan line rates, a team of three professional interpreters independently mapped thematically the selected geographic phenomena that they could detect in orbital television imagery produced on a fourteen inch monitor and recorded photographically for analysis. Three thematic maps were compiled by each interpreter. The maps were: (1) transportation patterns; (2) other land use; and (3) physical regions. The results from the three interpreters are compared, agreements noted, and differences analyzed for cause such as disagreement on identification of phenomenon, visual acuity, differences in interpretation techniques, and differing professional backgrounds.

Latham, J. P.↗
NASA NTRS1974

Landing approach evaluation of an integrated CRT display for general aviation aircraft

A flight director adaptable to general aviation aircraft was evaluated for the landing approach task in a twin turbojet business aircraft. The flight director combined aircraft heading, pitch and roll atitude, and ILS (Instrument Landing System) signals into a single picture on a small cathode ray tube (CRT) to give the pilot an integrated picture of the aircraft situation. The display is unique in that it presents the information on a CRT and gives quasi-command signals to the pilot. The particular display investigated was a preproduction version of the Kaiser Model FP-50 flight director. Approaches made with visual references only, with a conventional ILS displacement instrument, and with the CRT display were compared in terms of tracking performance and pilot workload. Tracking performance of three research pilots using the CRT display was superior to that using the conventional ILS instrument and comparable to that under VFR conditions. Pilot workload (based on pilot comments) was not clearly decreased.

Talbot, P. D.↗
NASA NTRS1974

A full-scale fire program to evaluate new furnishings and textile materials developed by the National Aeronautics and Space Administration

A program of experimental fires was carried out to establish the advantages offered by new materials for improved fire safety. Four full-scale bedrooms, differing only in the materials used to furnish them, were built and burned to provide comparative data on the fire hazards produced. Cost and availability differences were not considered. The visual evidence provided by TV and photographic coverage of the four experimental room fires showed clearly that the rooms responded very differently to a common ignition condition. Resistance to the ignition and spread of fire was substantially improved in the rooms furnished completely or partially with the new materials.

Hillenbrand, L. J.↗
NASA NTRS1973

Optical transmission in a circumstellar dust cloud

It is shown from the equation of radiative transfer that the visual attenuation of an optically thick, spherically symmetric circumstellar cloud of dust can be small compared to that produced by an equal optical depth of interstellar dust. The reasons for this are the moderately large albedos of the grains and their tendency to emphasize forward scattering.

Jones, T. W.↗
NASA NTRS1977

Aircraft wake-vortex minimization by use of flaps

A survey was made of research on the alleviation of the trailing vortex hazard by altering span loading with flaps on the generator airplane. Flap configurations of the generator that shed multiple vortices were found to have wakes that dispersed by vortex merging and sinusoidal instability. Reductions of approximately 50 percent in both the wake rolling moment imposed on a following aircraft and the aircraft separation requirement were achieved in the ground based and flight test experiments by deflecting the trailing edge flaps more inboard than outboard. Significantly, this configuration did not increase the drag or vibration on the generating aircraft compared to the conventional landing configuration. Ground based results of rolling moment measurement and flow visualization are shown, using a water tow facility, an air tow facility, and a wind tunnel. Flight test results are also shown, using a full scale B-747 airplane. General agreement was found among the results of the various ground based facilities and the flight tests.

Corsiglia, V. R.↗
NASA NTRS1980

The optically thin dust shell of Nova Cygni 1978

Nova Cygni 1978 was monitored photometrically from V to 19.5 microns for 120 days after the eruption. Following the initial expansion of the hot gas shell, an optically thin dust shell formed and reached a maximum visual optical depth of about 0.1 by day 60. No visible transition phase of the type observed in the very dusty DQ Herculis novae occurred in Nova Cygni 1978. It is argued that dust grain growth was inhibited because of the low mass of condensable atoms in the shell. Although the dust shell in Nova Cygni 1978 was optically thin at visual and infrared wavelengths, the grains grew to a radius of 0.3 micron which is comparable to the radius of the grains which grow in the optically thick shells of the DQ Herculis type novae.

Gehrz, R. D.↗
NASA NTRS1984

Hovering model helicopter rotor testing

A relatively large test chamber, chosen to minimize room interference effects during helicopter hovering rotor tests, was found in initial operations to exhibit large, random variations of thrust, torque, and blade flapping. The source of these problems, unsteady recirculation of test chamber flow, was addressed by the addition of a 'flow straightener' that reduced these parameter variations to 1.5 percent of mean values. Rotor performance was then measured outside the chamber in calm, free air conditions and compared with chamber results obtained before and after modifications. Attention is given to wake flow visualization conducted in the test chamber, as well as outside.

Piziali, R. A.↗
NASA NTRS1988

Aerodynamics of vortex generators

An experimental and theoretical study was undertaken of the separation delay and dramatic boundary-layer thinning that can occur in vortex-generator installations. Wind tunnel measurements of the dynamic-pressure profile downstream of a vortex generator were found to compare under certain conditions with that downstream of a suction slit, while water-tunnel visualization studies of vortex-generator height and geometry suggested optimum configurations, and only a minor effect of base porosity. A series of progressively more complex inviscid flow models was developed to be applied to a 3-D integral boundary-layer code. This code predicted layer thinning downstream of the suction site of the vortex models, and other observed features. Thin-layer Navier-Stokes equations are now being used with the ultimate goal of clarifying the physical processes involved in vortex generator performance and developing calculational procedures capable of predicting it.

Breidenthal, Robert E., Jr.↗
NASA NTRS1992

On the nature of the symbiotic binary AX Persei

Photometric and spectroscopic observations of the symbiotic binary AX Persei are presented. This system contains a red giant that fills its tidal lobe and transfers material into an accretion disk surrounding a low-mass main-sequence star. The stellar masses - 1 solar mass for the red giant and about 0.4 solar mass for the companion - suggest AX Per is poised to enter a common envelope phase of evolution. The disk luminosity increases from L(disk) about 100 solar luminosity in quiescence to L(disk) about 5700 solar luminosity in outburst for a distance of d = 2.5 kpc. Except for visual maximum, high ionization permitted emission lines - such as He II - imply an EUV luminosity comparable to the disk luminosity. High-energy photons emitted by a hot boundary layer between the disk and central star ionize a surrounding nebula to produce this permitted line emission. High ionization forbidden lines form in an extended, shock-excited region well out of the binary's orbital plane and may be associated with mass loss from the disk.

Mikolajewska, Joanna↗
NASA NTRS1993

Stellar multiple systems - Constraints on the mechanism of origin

The discovery rate of premain-sequence binary and multiple systems has increased dramatically over the last few years, providing us with our first insights into the nature of such systems at young ages. The observational data derived from spectroscopic, occultation, speckle, visual, and other techniques are reviewed. Where possible, the premain-sequence binary population is compared with main-sequence systems. These results are interpreted in terms of binary formation mechanisms. While wide binaries (P is greater than 100 yr) are ordinarily explained by a fragmentation process during the collapse of a rotating protostar, the origin of some systems by capture is a possibility. The origin of close systems is not well understood: various processes, such as fragmentation during late stages of collapse, gravitational instabilities in disks, or orbital decay from a longer-period system are examined.

Bodenheimer, Peter↗
NASA NTRS1992

Visualizing the universe, part 1

These decades are the first in which we can begin to map the universe. Recent surveys reveal patterns in the distribution of galaxies -- patterns coherent on scales of 150 million light years or more. These patterns contrast with the smoothness of the radiation background measured by the COBE satellite. Together these observations challenge our understanding of the origin of galaxies and large-scale structure in the universe. 'Visualizing the universe' is crucial for exploring the 3-dimensional maps, for analyzing them, for comparing the data with simulations, for designing instruments to make deeper maps with new large telescopes, and for sharing the excitement of discovery with the public.

Geller, M. J.↗
NASA NTRS1996

Unsteady Simulation of the Viscous Flow About a V-22 Rotor and Wing in Hover

Results of an unsteady thin-layer Navier-Stokes simulation of a 0.658-scale V-22 rotor and wing configuration in hover are presented. All geometric components of the flapped-wing and rotor test rig, including rotor blades, are accurately modeled. Rotor motion and rotor/airframe interference effects are simulated directly using moving body overset grid methods. Tiltrotor hover aerodynamics are visualized via unsteady particle trace images. Wing download predictive ability is demonstrated. Simulation results are compared with experimental data.

Meakin, Robert L.↗
NASA NTRS1999

Time-on-task decrements in "steer clear" performance of patients with sleep apnea and narcolepsy

Loss of attention with time-on-task reflects the increasing instability of the waking state during performance in experimentally induced sleepiness. To determine whether patients with disorders of excessive sleepiness also displayed time-on-task decrements indicative of wake state instability, visual sustained attention performance on "Steer Clear," a computerized simple RT driving simulation task, was compared among 31 patients with untreated sleep apnea, 16 patients with narcolepsy, and 14 healthy control subjects. Vigilance decrement functions were generated by analyzing the number of collisions in each of six four-minute periods of Steer Clear task performance in a mixed-model analysis of variance and linear regression equations. As expected, patients had more Steer Clear collisions than control subjects (p=0.006). However, the inter-subject variability in errors among the narcoleptic patients was four-fold that of the apnea patients, and 100-fold that of the controls volunteers; the variance in errors among untreated apnea patients was 27-times that of controls. The results of transformed collision data revealed main effects for group (p=0.006), time-on-task (p=0.001), and a significant interaction (p=0.022). Control subjects showed no clear evidence of increasing collision errors with time-on-task (adjusted R2=0.22), while apnea patients showed a trend toward vigilance decrement (adjusted R2=0.42, p=0.097), and narcolepsy patients evidenced a robust linear vigilance decrement (adjusted R2=0.87, p=0.004). The association of disorders of excessive somnolence with escalating time-on-task decrements makes it imperative that when assessment of neurobehavioral performance is conducted in patients, it involves task durations and analyses that will evaluate the underlying vulnerability of potentially sleepy patients to decrements over time in tasks that require sustained attention and timely responses, both of which are key components in safe driving performance.

NASA Discipline Space Human Factors↗
NASA NTRS1998

A common network of functional areas for attention and eye movements

Functional magnetic resonance imaging (fMRI) and surface-based representations of brain activity were used to compare the functional anatomy of two tasks, one involving covert shifts of attention to peripheral visual stimuli, the other involving both attentional and saccadic shifts to the same stimuli. Overlapping regional networks in parietal, frontal, and temporal lobes were active in both tasks. This anatomical overlap is consistent with the hypothesis that attentional and oculomotor processes are tightly integrated at the neural level.

Non-NASA Center↗