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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 NTRS1976

Possible radio emission from Uranus at 0.5 MHz

Radio emission from the direction of Uranus has been detected in data from the Goddard radio astronomy experiment on the IMP-6 spacecraft. Previously, emission from the direction of Jupiter and Saturn had been observed by IMP-6 at a number of frequencies near 1 MHz and were identified through an analysis of the phase of the observed modulated signal detected from the spinning dipole antenna. This technique was applied to the direction of Uranus with possible positive results. Over the approximately 500 days of data, three to six bursts with unique spectral characteristics have been found. The events persisted less than 3 minutes and are strongest in intensity near 0.5 MHz. Identification with Uranus is confused by the likely presence of low-level terrestrial and solar emission. Because of the unfavorable angular separation of earth and Uranus, there is a possibility that the bursts are atypical terrestrial magnetospheric phenomena, although the uniqueness of the set of events indicates the probable detection of radiation from Uranus.

Brown, L. W.↗
NASA NTRS2002

Doppler Radar and Cloud-to-Ground Lightning Observations of a Severe Outbreak of Tropical Cyclone Tornadoes

Data from a single WSR-88D Doppler radar and the National Lightning Detection Network are used to examine the characteristics of the convective storms that produced a severe tornado outbreak within Tropical Storm Beryl's remnants on 16 August 1994. Comparison of the radar data with reports of tornadoes suggests that only 12 cells produced the 29 tornadoes that were documented in Georgia and the Carolinas on that date. Six of these cells spawned multiple tornadoes, and the radar data confirm the presence of miniature supercells. One of the cells was identifiable on radar for 11 hours, spawning tornadoes over a time period spanning approximately 6.5 hours. Time-height analyses of the three strongest supercells are presented in order to document storm kinematic structure and evolution. These Beryl mini-supercells were comparable in radar-observed intensity but much more persistent than other tropical cyclone-spawned tornadic cells documented thus far with Doppler radars. Cloud-to-ground lightning data are also examined for all the tornadic cells in this severe swarm-type tornado outbreak. These data show many of the characteristics of previously reported heavy-precipitation supercells. Lightning rates were weak to moderate, even in the more intense supercells, and in all the storms the lightning flashes were almost entirely negative in polarity. No lightning at all was detected in some of the single-tornado storms. In the stronger cells, there is some evidence that lightning rates can decrease during tornadogenesis, as has been documented before in some midlatitude tornadic storms. A number of the storms spawned tornadoes just after producing their final cloud-to-ground lightning flashes. These findings suggest possible benefits from implementation of observing systems capable of monitoring intracloud as well as cloud-to-ground lightning activity.

McCaul, Eugene W., Jr.↗
NASA NTRSDate not supplied

Methodology Report of Cost Benefit Analysis of Space Based Solar Power

Space-based solar power (SBSP) is the concept of gathering power in space and transmitting it wirelessly to users on Earth or elsewhere in space. SBSP has seen renewed interest from governments, businesses, and universities for reasons including persistent operations in space, achieving carbon neutrality targets, and more. Several major government agencies in Europe, Asia, and the Americas have renewed their SBSP investigations, and hundreds of millions of dollars have been donated to universities to advance the technical state of the art. Given the renewed interest, this study will identify and update some key system parameters to current performance levels. This paper presents the methodology and approach to identify the fiscal and environmental costs and benefits of SBSP when compared to other sustainable and grid-scale energy sources. From these divergent angles the models evaluate fiscal and environmental impacts, identify the state of the most sensitive parameters of the designs, and seek to provide context to leadership on the relative value of pursuing SBSP related technologies.

Space-based solar power↗
NASA NTRS2001

Integrating Public Perspectives in Sample Return Planning

Planning for extraterrestrial sample returns, whether from Mars or other solar system bodies, must be done in a way that integrates planetary protection concerns with the usual mission technical and scientific considerations. Understanding and addressing legitimate societal concerns about the possible risks of sample return will be a critical part of the public decision making process ahead. This paper presents the results of two studies, one with lay audiences, the other with expert microbiologists, designed to gather information, on attitudes and concerns about sample return risks and planetary protection. Focus group interviews with lay subjects, using generic information about Mars sample return and a preliminary environmental impact assessment, were designed to obtain an indication of how the factual content is perceived and understood by the public. A research survey of microbiologists gathered information on experts' views and attitudes about sample return, risk management approaches and space exploration risks. These findings, combined with earlier research results on risk perception, will be useful in identifying levels of concern and potential conflicts in understanding between experts and the public about sample return risks. The information will be helpful in guiding development of the environmental impact statement and also has applicability to proposals for sample return from other solar system bodies where scientific uncertainty about extraterrestrial life may persist at the time of mission planning.

Race, Margaret S.↗
NASA NTRS2003

Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586 during its 2002 Outburst

An outburst of more thm 80 individual bursts, similar to those see^ from Soft Gamma Repeaters (SGRs), was detected from the Anomalous X-ray Pulsar (AXP) 1E 2259+586 in 2002 June. Coincident with this burst activity were gross changes in the pulsed flux, persistent flux, energy spectrum, pulse profile and spin down of the underlying X-ray source. We present Rossa X-ray Tirnsng Explorer and X-ray Multi-Mirror Mission observations of 1E 2259+586 that show the evolution of the aforementioned source parameters during and following this episode and identify recovery time scales for each. Specifically, we observe an X-ray flux increase (pulsed and phase-averaged) by more than an order of magnitude having two distinct components. The first component is linked to the burst activity and decays within approx. 2 days during which the energy spectrum is considerably harder than during the quiescent state of the source. The second component decays over the year following the glitch according to a power law in time with an exponent -0.22+/-0.01. The pulsed fraction decreased initially to approx. 15% RMS, but recovered rapidly to the pre-outburst level of approx. 2 3 % within the first three days.

Woods, P. M.↗
NASA NTRS2004

Autonomous Component Health Management with Failed Component Detection, Identification, and Avoidance

This paper details a novel scheme for autonomous component health management (ACHM) with failed actuator detection and failed sensor detection, identification, and avoidance. This new scheme has features that far exceed the performance of systems with triple-redundant sensing and voting, yet requires fewer sensors and could be applied to any system with redundant sensing. Relevant background to the ACHM scheme is provided, and the simulation results for the application of that scheme to a single-axis spacecraft attitude control system with a 3rd order plant and dual-redundant measurement of system states are presented. ACHM fulfills key functions needed by an integrated vehicle health monitoring (IVHM) system. It is: autonomous; adaptive; works in realtime; provides optimal state estimation; identifies failed components; avoids failed components; reconfigures for multiple failures; reconfigures for intermittent failures; works for hard-over, soft, and zero-output failures; and works for both open- and closed-loop systems. The ACHM scheme combines a prefilter that generates preliminary state estimates, detects and identifies failed sensors and actuators, and avoids the use of failed sensors in state estimation with a fixed-gain Kalman filter that generates optimal state estimates and provides model-based state estimates that comprise an integral part of the failure detection logic. The results show that ACHM successfully isolates multiple persistent and intermittent hard-over, soft, and zero-output failures. It is now ready to be tested on a computer model of an actual system.

Davis, Robert N.↗
NASA NTRSDate not supplied

The Plant Water Management Experiments: Hydroponics 3 & 4

As humans consider longer-duration missions in space, NASA has identified production of fresh vegetables aboard spacecraft as beneficial for crew nutrition, mental wellbeing, and enabling bioregenerative life support (i.e., air, water, and waste processing). Current low-g plant growth techniques have successfully grown a variety of leafy and flowering plants. However, unique microgravity fluidics challenges to maintain plant moisture levels persist which hamper overall system reliability. The Plant Water Management (PWM) experiments seek to demonstrate low-cost, low-mass, reusable plant growth systems that leverage recent advances in low-g capillary fluidics phenomena to provide routine, largely passive, water delivery to plants. This paper presents findings from a series of PWM-Hydroponics 3 & 4 experiments, which were collected during three ISS flight operations that occurred in March, May, and July of 2021. Open hydroponic capillary channel flows with synthetic evapo-transpiring plant models were used. Tests demonstrated flow stability for single and parallel channel flow configurations across a range of flow rates, plant types, and plant arrangements. Technology demonstrations of both passive aeration and bubble phase separation are reported. We provide details of the data reduction and archive. Insights from the successful flight demonstrations provide a foundation from which follow-on PWM-Hydroponics 5 & 6 experiments on ISS, potentially incorporate living plants, are being considered. Xx Summary of positives and negatives..

Marc B. Wasserman↗
NASA NTRS1994

Mixing processes within the polar night jet

Lagrangian material line simulations are performed using U.K. Meteorological Office simulated winds and temperatures to examine mixing processes in the middle- and lower-stratospheric polar night jet during the 1992 Southern Hemisphere spring and Northern Hemisphere winter. The Lagrangian simulations are undertaken to provide insight into the effects of mixing within the polar night jet on observations of the polar vortex made by instruments onboard the Upper Atmosphere Research Satellite (UARS) during these periods. A moderate to strong kinematic barrier to large-scale isentropic exchange, similar to the barrier identified in General Circulation Model (GCM) simulations, is identified during both of these periods. Characteristic timescales for mixing by large-scale isentropic motions within the polar night jet range from 20 days in the Southern Hemisphere lower stratosphere to years in the Northern Hemisphere middle stratosphere. The long mixing timescales found in the Northern Hemisphere polar night jet do not persist. Instead, the Northern Hemisphere kinematic barriers are broken down as part of the large-scale stratospheric response to a strong tropospheric blocking event. A series of Lagrangian experiments are conducted to investigate the sensitivity of the kinematic barrier to diabatic effects and to small-scale inertial gravity wave motions. Differential diabatic descent is found to have a significant impact on mixing processes within the Southern Hemisphere middle-stratospheric jet core. The interaction between small-scale displacements by idealized, inertial gravity waves and the large-scale flow is found to have a significant impact on mixing within the polar night jet in both hemispheres. These sensitivity experiments suggest that scales of motion that are unresolved in global assimilated datasets may contribute to mass exchange across the kinematic barrier to large-scale isentropic motion.

Pierce, R. Bradley↗
NASA NTRS2008

Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station

The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of precipitation at the SLF, and 6) strongest wind in the lowest 3000 ft. The forecast tool was developed as a graphical user interface with Microsoft Excel to help the forecaster enter the variables, and run the appropriate regression equations. Based on the forecaster's input and regression equations, a forecast of the day's peak and average wind is generated and displayed. The application also outputs the probability that the peak wind speed will be ^ 35 kt, 50 kt, and 60 kt.

Barrett, Joe, III↗
NASA NTRS2012

Spatial Distribution of Rolled up Kelvin-Helmholtz Vortices at Earth's Dayside and Flank Magnetopause

The Kelvin-Helmholtz Instability (KHI) can drive waves at the magnetopause. These waves can grow to form rolled-up vortices and facilitate transfer of plasma into the magnetosphere. To investigate the persistence and frequency of such waves at the magnetopause we have carried out a survey of all Double Star 1 magnetopause crossings, using a combination of ion and magnetic field measurements. Using criteria originally used in a Geotail study made by Hasegawa et al. (2006) (forthwith referred to as H2006), 17 candidate events were identified from the entire TC-1 mission (covering 623 orbits where the magnetopause was sampled), a majority of which were on the dayside of the terminator. The relationship between density and shear velocity was then investigated, to identify the predicted signature of a rolled up vortex from H2006 and all 17 events exhibited some level of rolled up behavior. The location of the events had a clear dawn-dusk asymmetry, with 12 (71 %) on the post noon, dusk flank suggesting preferential growth in this region.

dawn-dusk asymmetry↗
NASA NTRS2016

NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg(sup 2) region around SgrA* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of approx. 4× and approx. 8 ×10(exp 32) erg/s at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%-60%). Both spectral analysis and logN-logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single temperature thermal plasma model or an average photon index of Lambda = 1.5-2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.

center - X-rays: binaries - diffuse background↗
NASA NTRS2014

Clustering Days with Similar Airport Weather Conditions

On any given day, traffic flow managers must often rely on past experience and intuition when developing traffic flow management initiatives that mitigate imbalances between the aircraft demand and the weather impacted airport capacity. The goal of this study was to build on recent efforts to apply data mining classification and clustering algorithms to vast archives of historical weather and air traffic data to identify patterns and past decisions that can ultimately inform day-of-operations decision-making. More specifically, this study identified similar weather impacted days at select U.S. airports, and analyzed the traffic management initiatives implemented on these representative days. The identification of the similar days was accomplished by applying a decision tree algorithm to the hourly Localized Aviation Model Output Statistics Program observations and the arrival delays for Newark Liberty International Airport. The branches from the trained decision tree were subsequently pruned to identify four weather conditions that resulted in medium to high delays for the arrivals scheduled to Newark in 2012. Using these weather conditions, four, daily airport-level Weather Impacted Traffic Index values were calculated using the Localized Aviation Model Output Statistics Program observations and the 2012 scheduled arrival counts from the FAAs Aviation System Performance Metric system. The four, daily Weather Impacted Traffic Index values for 2012 were subsequently clustered using an Expectation Maximization clustering algorithm, and nine unique types of weather days at Newark were identified. By far the most prominent type of day at Newark was a day associated with relatively good weather conditions, where there was little convective activity, winds were low, ceilings and visibility were high and there was little precipitation. Moderate levels of convective activity characterized the next most prominent type of day. Days with persistently high winds or low ceiling and visibility levels were relatively rare in 2012. Lastly, the frequency at which Ground Delay Programs, Ground Stops and Miles-in-Trail restrictions were implemented on each of the typical types of days at Newark were analyzed. Based on the results, it does appear as if the usage of Miles-in-Trail, Ground Delay Program and Ground Stop restrictions correlates well with the severity of the weather associated with each unique type of weather impacted day at Newark. Furthermore, the results demonstrate that it is feasible to use historical weather and air traffic archives to provide guidance on the types of traffic management restrictions to implement in response to the weather conditions impacting an airport.

traffic flow management↗
NASA NTRS2014

Clustering Days with Similar Airport Weather Conditions

On any given day, traffic flow managers must often rely on past experience and intuition when developing traffic flow management initiatives that mitigate imbalances between the aircraft demand and the weather impacted airport capacity. The goal of this study was to build on recent efforts to apply data mining classification and clustering algorithms to vast archives of historical weather and air traffic data to identify patterns and past decisions that can ultimately inform day-of-operations decision-making. More specifically, this study identified similar weather impacted days at select U.S. airports, and analyzed the traffic management initiatives implemented on these representative days. The identification of the similar days was accomplished by applying a decision tree algorithm to the hourly Localized Aviation Model Output Statistics Program observations and the arrival delays for Newark Liberty International Airport. The branches from the trained decision tree were subsequently pruned to identify four weather conditions that resulted in medium to high delays for the arrivals scheduled to Newark in 2012. Using these weather conditions, four, daily airport-level Weather Impacted Traffic Index values were calculated using the Localized Aviation Model Output Statistics Program observations and the 2012 scheduled arrival counts from the FAAs Aviation System Performance Metric system. The four, daily Weather Impacted Traffic Index values for 2012 were subsequently clustered using an Expectation Maximization clustering algorithm, and nine unique types of weather days at Newark were identified. By far the most prominent type of day at Newark was a day associated with relatively good weather conditions, where there was little convective activity, winds were low, ceilings and visibility were high and there was little precipitation. Moderate levels of convective activity characterized the next most prominent type of day. Days with persistently high winds or low ceiling and visibility levels were relatively rare in 2012. Lastly, the frequency at which Ground Delay Programs, Ground Stops and Miles-in-Trail restrictions were implemented on each of the typical types of days at Newark were analyzed. Based on the results, it does appear as if the usage of Miles-in-Trail, Ground Delay Program and Ground Stop restrictions correlates well with the severity of the weather associated with each unique type of weather impacted day at Newark. Furthermore, the results demonstrate that it is feasible to use historical weather and air traffic archives to provide guidance on the types of traffic management restrictions to implement in response to the weather conditions impacting an airport.

weather↗
NASA NTRS2014

Persistent Expression Changes of Fibrosis-Related Genes in the Lung Tissues of Rats Exposed to Lunar Dust Particles

The Moon's surface is covered by a layer of fine, potential reactive dust. Lunar dust contain about 1‐2% of very fine respirable dust (less than 3 micrometers). The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust‐induced changes of the expression of fibrosis‐related genes, and to identify specific signaling pathways involved in lunar dustinduced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose‐only inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 milligrams per cubic meters of lunar dust. Five rats per group were euthanized at 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The bronchoalveolar lavage fluid (BALF) was collected by lavaging with phosphate‐buffered saline (PBS). A zymosan‐induced luminolbased chemiluminescence assay was used to assess the activity of BAL cells. The lavaged lung tissue was snap frozen in LN2 and total RNA was isolated using the Qigen RNeasy kit. The expression of 84 fibrosisrelated genes were analyzed using the RT2 Profiler PCR Array technique. The expression of 18 genes of interest were further measured using real‐time PCR technique in all the samples. 10 out of 18 genes of interest showed persistently significant expression changes in the local lung tissue exposed to lunar dust, indicating a prolonged proinflammatory response. The expressions of several of these genes were dose‐ and time‐dependent and were significantly correlated with other pathological parameters. The potential signaling pathways and upstream regulators were further analyzed using IPA pathway analysis tool based on the gene expression data. The data presented in this study, for the first time, explore the molecular mechanisms of lunar dust induced toxicity, contributing not only the risk assessment for future space exploration, but also understandings of the dust‐induced toxicity in humans on earth.

Zhang, Ye↗
NASA NTRSDate not supplied

Indigenous Organic Matter Associated with Unusual Low Temperature Aqueous Secondary Phases in the Mars Meteorite Nakhla

In freshly fractured chips of the Mars meteorite Nakhla, we found carbonaceous phases intimately associated with secondary aqueous alteration phases, both mineral and amorphous, interpreted to have formed through the low-temperature, mineral-water dissolution of the host Martian basalt.We have characterized the nature of carbonaceous matter and spatially associated secondary phases within Nakhla using a multidisciplinary suite of optical and electron beam instrumentation(Thomas-Keprta et al., 2022). Secondary Phases: The preserved secondary mineral phases are best described as ‘juvenile’ hydrated amorphous silica formed when water interacts with mafic rocks. Although amorphous silica on Earth rarely persists through geologic time due to alteration into other phases, e.g.,microcrystalline opal-CT and eventually quartz, the lack of maturation of primarily amorphous silica with embedded nano phase ferrihydrite in Nakhla infers these phases formed in a limited water environment by low temperature, circumneutral pH fluids stabilized by the presence of coexisting amorphous silica.Additionally, we report the presence of the ferrous hydroxycarbonate mineral chukanovite (Fe2(OH)2CO3)within some of the secondary mineral aggregates studied. Organic Matter:Indigenous Nakhla carbonaceous matter is present both in condensed phases and in a dispersed state spatially associated with secondary alteration phases. In the former, discrete refractory micron to submicron assemblages were identified that appear macromolecular in nature and, in several cases, associated with F and, in one case, significant N. While organically bound Fhas yet to be detected remotely on Mars, the identification of organic N within one of the carbonaceous phases is considered a prerequisite for Martian astrobiological potential. Summary: Neither the intimate association of carbonaceous matter with secondary phases nor the identification of chukanovite have been previously reported in any of the Martian meteorites.A variety of habitability-related metastable solid-phase, oxidation-reduction, and organic-molecular sample attributes in Nakhla formed hundreds of millions of years ago near Mars’ surface; these alteration products persisted on Mars until very recentlyand resemble the amorphous materials observed at Gale crater by Mars Science Laboratory CuriosityRover (Rampe et al., 2020).Similar phases may be expected to occur elsewhere on Mars (e.g., Jezerocrater). References: Rampe E. B. et al.(2020) Mineralogy and geochemistry of sedimentary rocks and eolian sediments in Gale crater, Mars: A review after six Earth years of exploration with Curiosity.Geochemistry80, 125605; Thomas-Keprta K.L. et al. (2022) Indigenous carbon-rich matter associated with unusual aqueous alteration features in Nakhla: Complex formation and preservation history. Geochim. et Cosmochim. Acta320, 41-78 (online).

Mars meteorite↗
NASA NTRS1997

Persistent Sub-Yearly Chromospheric Variations in Lower Main-Sequence Stars: Tau Booe and alpha Com

The recent discoveries of extrasolar planetary systems around lower main-sequence stars such as tau Booe (HD 120136) has prompted further investigation into their stellar activity. A cursory analysis of tau Booe for cyclic chromospheric activity, based on its 30-yr record of Ca 2 H and K fluxes obtained as part of the HK Project from Mount Wilson Observatory, finds an intermediate, sub-yearly period (approximately 117 d) in chromospheric activity in addition to, and separate from, both its rotation (3.3 d) and long-term variability. As a persistent subyearly period in surface magnetic activity is unprecedented, we investigate this apparent anomaly further by examining chromospheric activity levels of other stars with similar mass, searching for variability in chromospheric activity with periods of less than one year, but longer than measured or predicted rotation. An examination of the time series of 40 mid-to-late F dwarfs yielded one other star for further analysis: alpha Com (HD 114378, P approximately 132 d). The variations for these two stars were checked for persistence and coherence. Based on these determinations, we eliminate the possibilities of rotation, long-term activity cycle, and the evolution of active regions as the cause of this variation in both stars. In particular, for tau Booe we infer that the phenomenon may be chromospheric in origin; however, beyond this, it is difficult to identify anything further regarding the cause of the activity variations, or even whether the observed modulation in the two stars have the same origin.

Maulik, Davesh↗
NASA NTRS1994

High charge state carbon and oxygen ions in Earth's equatorial quasi-trapping region

Observations of energetic (1.5 - 300 keV/e) medium-to-high charge state (+3 less than or equal to Q less than or equal to +7) solar wind origin C and O ions made in the quasi-trapping region (QTR) of Earth's magnetosphere are compared to ion trajectories calculated in model equatorial magnetospheric magnetic and electric fields. These comparisons indicate that solar wind ions entering the QTR on the nightside as an energetic component of the plasma sheet exit the region on the dayside, experiencing little or no charge exchange on the way. Measurements made by the CHarge Energy Mass (CHEM) ion spectrometer on board the Active Magnetospheric Particle Tracer Explorer/Charge Composition Explorer (AMPTE/CCE) spacecraft at 7 less than L less than 9 from September 1984 to January 1989 are the source of the new results contained herein: quantitative long-term determination of number densities, average energies, energy spectra, local time distributions, and their variation with geomagnetic disturbance level as indexed by Kp. Solar wind primaries (ions with charge states unchanged) and their secondaries (ions with generally lower charge states produced from primaries in the magnetosphere via charge exchange)are observed throughout the QTR and have distinctly different local time variations that persist over the entire 4-year analysis interval. During Kp larger than or equal to 3 deg intervals, primary ion (e.g., O(+6)) densities exhibit a pronounced predawn maximum with average energy minimum and a broad near-local-noon density minimum with average energy maximum. Secondary ion (e.g., O(+5)) densities do not have an identifiable predawn peak, rather they have a broad dayside maximum peaked in local morning and a nightside minimum. During Kp less than or equal to 2(-) intervals, primary ion density peaks are less intense, broader in local time extent, and centered near midnight, while secondary ion density local time variations diminish. The long-time-interval baseline helps to refine and extend previous observations; for example, we show that ionospheric contribution to O(+3)) is negligible. Through comparison with model ion trajectories, we interpret the lack of pronounced secondary ion density peaks colocated with the primary density peaks to indicate that: (1) negligible charge exchange occurs at L greater than 7, that is, solar wind secondaries are produced at L less than 7, and (2) solar wind secondaries do not form a significant portion of the plasma sheet population injected into the QTR. We conclude that little of the energetic solar wind secondary ion population is recirculated through the magnetosphere.

Christon, S. P.↗
NASA NTRS2014

FY13 High Performance EVA Glove (HPEG) Collaboration: Glove Injury Data Mining Effort - Training Data Overview

From the time hand-intensive tasks were first created for EVAs, discomforts and injuries have been noted.. There have been numerous versions of EVA gloves for US crew over the past 50 years, yet pain and injuries persist. The investigation team was tasked with assisting in a glove injury assessment for the High Performance EVA Glove (HPEG) project.center dot To aid in this assessment, the team was asked to complete the following objectives: - First, to develop the best current understanding of what glove-related injuries have occurred to date, and when possible, identify the specific mechanisms that caused those injuries - Second, to create a standardized method for comparison of glove injury potential from one glove to another. center dot The overall goal of the gloved hand injury assessment is to utilize ergonomics in understanding how these glove injuries are occurring, and to propose mitigations to current designs or design changes in the next generation of EVA gloves.

Reid, Christopher↗