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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 NTRS2000

Differences in Acceleration Training and Exercise Training on Resting Cardiovascular Variables

The relative effects of alternating exercise vs. acclamation training an mean blood pressure (BP, Finapres), cardiac output (CO, BoMed) and peripheral resistance (PR, calculated) were evaluated. Six healthy men (33$\pm$(SD)6 yr. 178$\pm$4 cm, 86$\pm$6 kg) underwent exercise training (ET, n=3): supine on a cycle ergometer (40 to 90\% Vo$_{2}$ max) during exposure to constant+1G$_{z}$ for $\sim$30 min/day for 14 days on NASA's 1.9m Human Powered Centrifuge (HPC). They also underwent oscillatory (between +1 G$ {z}$and$\sim$2.5G$_{z}$) acceleration training (AT, n=3) for $\sim$30 min/day for 14 days on the HPC. After four weeks of ambulatory deconditioning, training protocols were switched. AT increased resting CO by 9.MpmS(SE)3.2\% (p$less than$0.05) with no effect on BF, and ET decreased BP by 9.2$\pm$4.6\% (p$less than$0.08) as well as spectral power of PR by 41$\pm$9\% (p$less than$0.05). The major effect of acceleration training was to increase resting cardiac output while that of exercise mining was to decrease resting blood pressure.

Evans, J. M.↗
NASA NTRS2003

Pristine Impact Crater Populations of Mars

This study focused on obtaining size frequency distributions of pristine crater populations from various terrains of Mars. Images from the Viking Orbiter (VO), Mars Orbital Camera (MOC), and Thermal Emission Imaging System (THEMIS) were utilized for this study. The results may aid in providing information about crater production functions and resurfacing events on Mars.

Chauhan, R. V.↗
NASA NTRS2003

High Voltage Solar Array ARC Testing for a Direct Drive Hall Effect Thruster System

The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (112HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration "trigger" arcs as well as long duration "sustained" arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of vo!tage, (current and power. The data will be used to propose a new, high-voltage (>300 V) solar array design for which the likelihood of damage from arcing is minimal.

Schneider, T.↗
NASA NTRS2002

Lower-body negative-pressure exercise and bed-rest-mediated orthostatic intolerance

PURPOSE: Supine, moderate exercise is ineffective in maintaining orthostatic tolerance after bed rest (BR). Our purpose was to test the hypothesis that adding an orthostatic stress during exercise would maintain orthostatic function after BR. METHODS: Seven healthy men completed duplicate 15-d 6 degrees head-down tilt BR using a crossover design. During one BR, subjects did not exercise (CON). During another BR, subjects exercised for 40 min.d(-1) on a supine treadmill against 50-60 mm Hg LBNP (EX). Exercise training consisted of an interval exercise protocol of 2- to 3-min intervals alternating between 41 and 65% (.)VO(2max). Before and after BR, an LBNP tolerance test was performed in which the LBNP chamber was decompressed in 10-mm Hg stages every 3 min until presyncope. RESULTS: LBNP tolerance, as assessed by the cumulative stress index (CSI) decreased after BR in both the CON (830 +/- 144, pre-BR vs 524 +/- 56 mm Hg.min, post-BR) and the EX (949 +/- 118 pre-BR vs 560 +/- 44 mm Hg.min, post-BR) conditions. However, subtolerance (0 to -50 mm Hg LBNP) heart rates were lower and systolic blood pressures were better maintained after BR in the EX condition compared with CON. CONCLUSION: Moderate exercise performed against LBNP simulating an upright 1-g environment failed to protect orthostatic tolerance after 15 d of BR.

NASA Center JSC↗
NASA NTRS2001

Determining the amount of physical activity needed for long-term weight control

OBJECTIVE: To evaluate prospectively the influence of habitual physical activity on body weight of men and women and to develop a model that defines the role of physical activity on longitudinal weight change. DESIGN AND SETTING: Occupational cohort study conducted for a mean of 5.5 y. SUBJECTS: A total of 496 (341 male and 155 female) NASA/Johnson Space Center employees who completed the 3 month education component of the employee health-related fitness program and remained involved for a minimum of 2 y. MEASUREMENTS: Body weights were measured at baseline (T1) and follow-up (T2), and habitual physical activity was obtained from the mean of multiple ratings of the 11-point (0-10) NASA Activity Scale (NAS) recorded quarterly between T1 and T2. Other measures included age, gender, VO(2 max) obtained from maximal treadmill testing, body mass index (BMI), and body fat percentage. RESULTS: Multiple regression demonstrated that mean NAS, T1 weight, aging and gender all influence long-term T2 weight. T1 age was significant for the men only. Independently, each increase in mean NAS significantly (P<0.01) reduced T2 weight in men (b=-0.91 kg; 95% CI:-1.4 to-0.42 kg) and women (b=-2.14 kg; 95% CI:-2.93 to-1.35 kg). Mean NAS had a greater effect on T2 weight as T1 weight increased, and the relationship was dose-dependent. CONCLUSIONS: Habitual physical activity is a significant source of long-term weight change. The use of self-reported activity level is helpful in predicting long-term weight changes and may be used by health care professionals when counseling patients about the value of physical activity for weight control.

Exercise↗
NASA NTRS2005

Virtual Observatory Science Applications

Many Virtual-Observatory-based applications are now available to astronomers for use in their research. These span data discovery, access, visualization and analysis. Tools can quickly gather and organize information from sites around the world to help in planning a response to a gamma-ray burst, help users pick filters to isolate a desired feature, make an average template for z=2 AGN, select sources based upon information in many catalogs, or correlate massive distributed databases. Using VO protocols, the reach of existing software tools and packages can be greatly extended, allowing users to find and access remote information almost as conveniently as local data. The talk highlights just a few of the tools available to scientists, describes how both large and small scale projects can use existing tools, and previews some of the new capabilities that will be available in the next few years.

McGlynn, Tom↗
NASA NTRS2004

Grid Enabled Geospatial Catalogue Web Service

Geospatial Catalogue Web Service is a vital service for sharing and interoperating volumes of distributed heterogeneous geospatial resources, such as data, services, applications, and their replicas over the web. Based on the Grid technology and the Open Geospatial Consortium (0GC) s Catalogue Service - Web Information Model, this paper proposes a new information model for Geospatial Catalogue Web Service, named as GCWS which can securely provides Grid-based publishing, managing and querying geospatial data and services, and the transparent access to the replica data and related services under the Grid environment. This information model integrates the information model of the Grid Replica Location Service (RLS)/Monitoring & Discovery Service (MDS) with the information model of OGC Catalogue Service (CSW), and refers to the geospatial data metadata standards from IS0 19115, FGDC and NASA EOS Core System and service metadata standards from IS0 191 19 to extend itself for expressing geospatial resources. Using GCWS, any valid geospatial user, who belongs to an authorized Virtual Organization (VO), can securely publish and manage geospatial resources, especially query on-demand data in the virtual community and get back it through the data-related services which provide functions such as subsetting, reformatting, reprojection etc. This work facilitates the geospatial resources sharing and interoperating under the Grid environment, and implements geospatial resources Grid enabled and Grid technologies geospatial enabled. It 2!so makes researcher to focus on science, 2nd not cn issues with computing ability, data locztic~, processir,g and management. GCWS also is a key component for workflow-based virtual geospatial data producing.

Chen, Ai-Jun↗
NASA NTRS2006

Twins Bed Rest Project: LBNP/Exercise Minimizes Changes in Lean Leg Mass, Strength and Endurance

Decreases in muscle strength and endurance frequently are observed in non-weightbearing conditions such as bed rest (BR), spaceflight or limb immobilization. Purpose: Ow purpose was to determine if supine treadmill exercise against simulated gravity, by application of lower body negative pressure (LBNP), prevents loss of lean leg mass, strength and endurance during 30 d of 6deg head-down bed rest (BR). Methods: Fifteen pairs of monozygous twins (8 male, 7 female pairs; 26+/-4 yrs; 170+/-12 cm; 62.6+/-11.3 kg; mean+/-SD) were subjects in the present study. One sibling of each pair of twins was randomly assigned to either an exercise (EX) or non-exercise (CON) group. The EX twin walked/jogged on a vertical treadmill within LBNP chamber 6 d/wk using a 40-min interval exercise protocol at 40-80% of pre-BR VO(sub 2peak). LBNP was adjusted individually for each subject such that footward force was between 1.0 and 1.2 times body weight (-53+/-5 mmHg LBNP). The CON twin performed no exercise during BR. Subjects performed isokinetic knee (60 and 120deg/s) and ankle (60deg/s) testing to assess strength and endurance (End) before and after BR. They also had their lean leg mass (L(sub mass)) evaluated by DEXA before and after BR. Results: Changes in peak torque (T(sub pk)) were smaller for flexion (flex) than for extension (ext) after BR and did not differ between groups. The CON group had larger decreases (P<0.05) in L(sub mass), knee and ankle ext T(sub pk), and knee ext End.

Amorim, Fabiano T.↗
NASA NTRS2006

GCN and VOEvent - A Status Report

The GRB Coordinates Network (GCN) has filled an important niche in the conduct and progress of research on GRB for more than 14 years. The methods used to collect and distribute the positions, lightcurves, spectra, and images on GRB is real time (a few seconds) will be reviewed. For the research on GRBs to continue to move forward and for other fields of transient astronomy to move forward, enhancements are needed to the GCN. VOEvents is one of those changes, and that addition will be described here. The enhanced system will be called VO-GCN.

Barthelmy, Scott↗
NASA NTRS2007

Heliophysics Data and Modeling Research Using VSPO

The primary advantage of Virtual Observatories in scientific research is efficiency: rapid searches for and access to data in convenient forms makes it possible to explore scientific questions without spending days or weeks on ancilary tasks. The Virtual Space Physics Observatory provides a general portal to Heliophysics data for this task. Here we will illustrate the advantages of the VO approach by examining specific geomagnetically active times and tracing the activity through the Sun-Earth system. In addition to previous and additional data sources, we will demonstrate an extension of the capabilities to allow searching for model run results from the range of CCMC models. This approach allows the user to quickly compare models and observations at a qualitative level; considerably more work will be needed to develop more seamless connections to data streams and the equivalent numerical output from simulations.

Roberts, D. Aaron↗
NASA NTRS2008

Near-Infrared Spectroscopic Measurements of Calf Muscle during Walking at Simulated Reduced Gravity - Preliminary Results

Consideration for lunar and planetary exploration space suit design can be enhanced by investigating the physiologic responses of individual muscles during locomotion in reduced gravity. Near-infrared spectroscopy (NIRS) provides a non-invasive method to study the physiology of individual muscles in ambulatory subjects during reduced gravity simulations. PURPOSE: To investigate calf muscle oxygen saturation (SmO2) and pH during reduced gravity walking at varying treadmill inclines and added mass conditions using NIRS. METHODS: Four male subjects aged 42.3 +/- 1.7 years (mean +/- SE) and weighing 77.9 +/- 2.4 kg walked at a moderate speed (3.2 +/- 0.2 km/h) on a treadmill at inclines of 0, 10, 20, and 30%. Unsuited subjects were attached to a partial gravity simulator which unloaded the subject to simulate body weight plus the additional weight of a space suit (121 kg) in lunar gravity (0.17G). Masses of 0, 11, 23, and 34 kg were added to the subject and then unloaded to maintain constant weight. Spectra were collected from the lateral gastrocnemius (LG), and SmO2 and pH were calculated using previously published methods (Yang et al. 2007 Optics Express ; Soller et al. 2008 J Appl Physiol). The effects of incline and added mass on SmO2 and pH were analyzed through repeated measures ANOVA. RESULTS: SmO2 and pH were both unchanged by added mass (p>0.05), so data from trials at the same incline were averaged. LG SmO2 decreased significantly with increasing incline (p=0.003) from 61.1 +/- 2.0% at 0% incline to 48.7 +/- 2.6% at 30% incline, while pH was unchanged by incline (p=0.12). CONCLUSION: Increasing the incline (and thus work performed) during walking causes the LG to extract more oxygen from the blood supply, presumably to support the increased metabolic cost of uphill walking. The lack of an effect of incline on pH may indicate that, while the intensity of exercise has increased, the LG has not reached a level of work above the anaerobic threshold. In these preliminary studies, 30% incline walking at reduced gravity may not require anaerobic LG activity due to the low exercise intensity (42.8 +/- 1.6% of VO(sub 2max)). It is also possible that at reduced gravity additional work is being done by muscle groups other than the calf.

Ellerby, Gwenn E. C.↗
NASA NTRS2010

Maximum Oxygen Uptake During and After Long-Duration Space Flight

Decreased maximum oxygen consumption (VO2max) during and after space flight may impair a crewmember s ability to perform mission-critical work that is high intensity and/or long duration in nature (Human Research Program Integrated Research Plan Risk 2.1.2: Risk of Reduced Physical Performance Capabilities Due to Reduced Aerobic Capacity). When VO2max was measured in Space Shuttle experiments, investigators reported that it did not change during short-duration space flight but decreased immediately after flight. Similar conclusions, based on the heart rate (HR) response of Skylab crewmembers, were made previously concerning long-duration space flight. Specifically, no change in the in-flight exercise HR response in 8 of 9 Skylab crewmembers indicated that VO2max was maintained during flight, but the elevated exercise HR after flight indicated that VO2max was decreased after landing. More recently, a different pattern of in-flight exercise HR response, and assumed changes in VO2max, emerged from routine testing of International Space Station (ISS) crewmembers. Most ISS crewmembers experience an elevated in-flight exercise HR response early in their mission, with a gradual return toward preflight levels as the mission progresses. Similar to previous reports, exercise HR is elevated after ISS missions and returns to preflight levels by 30 days after landing. VO2max has not been measured either during or after long-duration space flight. The purposes of the ISS VO2max experiment are (1) to measure VO2max during and after long-duration spaceflight, and (2) to determine if submaximal exercise test results can be used to accurately estimate VO 2max.

Moore, Alan D., Jr.↗
NASA NTRS2016

Motion Estimation Utilizing Range Detection-Enhanced Visual Odometry

A motion determination system is disclosed. The system may receive a first and a second camera image from a camera, the first camera image received earlier than the second camera image. The system may identify corresponding features in the first and second camera images. The system may receive range data comprising at least one of a first and a second range data from a range detection unit, corresponding to the first and second camera images, respectively. The system may determine first positions and the second positions of the corresponding features using the first camera image and the second camera image. The first positions or the second positions may be determined by also using the range data. The system may determine a change in position of the machine based on differences between the first and second positions, and a VO-based velocity of the machine based on the determined change in position.

Friend, Paul Russell↗
NASA NTRS2017

Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b

We find evidence for a strong thermal inversion in the dayside atmosphere of the highly irradiated hot Jupiter WASP-18b (equatorial temperature equals 2411 degrees Kelvin, mass equals 10.3 times the mass of Jupiter) based on emission spectroscopy from Hubble Space Telescope secondary eclipse observations and Spitzer eclipse photometry. We demonstrate a lack of water vapor in either absorption or emission at 1.4 microns. However, we infer emission at 4.5 microns and absorption at 1.6 microns that we attribute to CO, as well as a non-detection of all other relevant species (e.g., TiO, VO). The most probable atmospheric retrieval solution indicates a C/O ratio of 1 and a high metallicity (C/H equals 283 from plus 395 to minus 138 times solar). The derived composition and temperature/pressure profile suggest that WASP-18b is the first example of both a planet with a non-oxide driven thermal inversion and a planet with an atmospheric metallicity inconsistent with that predicted for Jupiter-mass planets at greater than 2 sigma. Future observations are necessary to confirm the unusual planetary properties implied by these results.

Sheppard, Kyle B.↗
NASA NTRS2015

NEOShield: Design of a Gravity Tractor Demonstration Mission

The Mission Design Division at NASA Ames Research Center has begun a program to develop mission designs for planetary defense. Here we present a mission design for a gravity tractor demonstration mission completed in collaboration with the European NEOShield consortium.We conducted a trade study to identify suitable target NEOs to demonstrate GT deflection, and identified 5 known asteroids with diameters between 100m and 500m that have been well studied in the past: 2000 FJ10, 2001 QC34, 2002 DU3, 2001 JV1 and 1998 VO. We selected 2000 FJ10 as the most suitable target to meet the requirements of a GT demonstration mission.Our GT demonstration spacecraft is based on an ESPA ring main structure and solar electric propulsion (SEP, see Figure 1). The power budget is 4 kW and the spacecraft has an initial wet mass of 1,150 kg. The spacecraft would launch in the 3rd quarter of 2026 aboard a Falcon 9, arriving at 2000 FJ10 in early 2029 after an unpowered Mars gravity assist in 2027. The spacecraft mass at asteroid arrival would be 1,100 kg.

Faber, N. T.↗
NASA NTRSDate not supplied

Evaluation of Aerobic Standards for Lunar Surface Extravehicular Activities

As NASA prepares to return to the Moon, astronauts will need to be physically primed to successfully execute Extravehicular Activities (EVA) on the Lunar surface. Compared to past Apollo missions, Artemis missions will include EVAs of increased physical demand, frequency, intensity, and duration, thus requiring adequate fitness to successfully and safely complete mission objectives. The physical demand associated with partial gravity (g) EVAs on the Moon is expected to be greater compared to microgravity EVAs based on initial workload estimation. Currently, aerobic fitness standards for partial g EVAs are not well supported by high-fidelity data and require further research for establishing standards to protect crew health and performance during Lunar surface missions. Therefore, the aim of this investigation is to characterize metabolic data from Lunar analog simulations and in-flight crew population aerobic capacity data to validate the current NASA 3001 standard for celestial partial g aerobic fitness (aerobic capacity (VO_2pk) ≥36.5ml/kg/min).

Nicole Strock↗