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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

ATD-2 TFDM Terminal Publication Service (TTP)

Learn the many benefits of the newest SWIM feed from the surface system. This will discuss current options to onboard with this feed, allow participants to ask questions and provide some examples of how the data can be used. Service Includes Flight Data Individual flight updates containing flight identifiers, targeted times, actual times, runway, parking gate, spot, departure fix (predicted, assigned, actual as appropriate), flight states, and more. Airport Information Airport configurations, airport and runway rates, ramp closures, runway closures, taxiway closures. Traffic Management Restrictions Call for Release programs departure MIT/MINIT restrictions, departure stop/ground stop programs. Along with list of impacted flights for each. Flight Delay Airport and runway delay by arrival, departure, and total. Operational Metrics Metrics on airport throughput and individual flight metrics. Surface Metering Program SMP start / end times, metering constraint type / details, updates to existing programs, TMAT compliance window, departure queue length, and more.

Gorman, Shawn M.↗
NASA NTRSDate not supplied

Some Effects of Tunnel Noise on Cylinder-Induced Mach 6 Transitional Shock Wave Boundary Layer Interactions

Experiments were conducted on a cylinder-induced shock wave boundary layer interaction (SBLI)as its state was brought through transition using a combination of boundary layer trips and Reynolds number sweep. A baseline case with no trips was also examined. The measurements were made in a Mach 6 freestream in the well-characterized Actively Controlled Expansion tunnel, which demonstrated a near tripling in fluctuation levels with unit Reynolds number increase from 3.0 to 3.5 million per meter. Surface oil flow and schlieren images suggested the jump in freestream noise served as the impetus for SBLI transition since the flow separation distance began to decrease as the Reynolds number progressed through those conditions. Likewise, surface mounted Kulite® pressure transducers indicated a rise in surface pressure fluctuations as well as initial growth in the instability responsible for transitioning the boundary layer within the interaction. Finally, heat transfer rates within the tripped SBLI were shown to be affected by the jump in freestream disturbance levels.

Andrew N Leidy↗
NASA NTRS1991

Meteoroid and orbital debris record of the Long Duration Exposure Facility

The Long Duration Exposure Facility (LDEF) was recovered in January 1990 following 5.7 years exposure of approx. 130 square meters of surface area in low-Earth orbit (250-179 miles). Kennedy Space Center acquired data are currently being reduced to yield accurate impact crater depths and diameters. Presented here is a preliminary accounting of the impact record based on the approx. 15.4 square meter surface area of LDEF's 6061-T6 aluminum frame, which was exposed in 26 different directions.

Zolensky, Mike↗
NASA NTRS1977

Experimental remote sensing of subsurface temperature in natural ocean water

The first successful depth-resolved remote sensing measurements of subsurface ocean water temperature were obtained by spectral analysis of the 3400 per cm O-H stretching Raman band of liquid water. Raman spectral data were obtained from a research vessel at various depths from the surface to 10 meters below the surface in a tidal estuary. The temperature inferred from the spectra was consistent with ground truth temperature to within the shot noise limited accuracy of plus or minus 2 C. The performance of a future fully developed airborne laser Raman water temperature measurement system is estimated on the basis of these first tests.

Leonard, D. A.↗
NASA NTRS2022

Rock Abundance on the Lunar Mare on Surfaces of Different Age: Implications for Regolith Evolution and Thickness

The growth of lunar regolith over time affects surface rock abundance, because larger, less frequent impacts are needed to penetrate thicker regolith developed on older surfaces and excavate rocks. On younger surfaces with thinner regolith, smaller, more frequent impacts are sufficient to excavate rocks. We quantify the correlation between observed rock abundances and age on the lunar surface by comparing Diviner rock abundance data to the surface ages of inter-crater parts on the maria. Our observations show the expected negative correlation between age and rock abundance. The commonality of non-zero rock abundance values on ancient surfaces, combined with a simple Monte Carlo model of the rock excavation process, suggest that rocks re-excavated from the regolith volume contribute to the presently observed rock population on the lunar surface. The half-life of meter-scale surface rocks most consistent with our observations is 80±20 Myr.

Sashank Vanga↗
NASA NTRS1988

The 15-meter diameter hoop/column antenna surface control actuator system

The design, development, and implementation status of the Surface Control Actuator System (SCAS) for the Hoop/Column Antenna are described with the primary focus on the design of the mechanical element. The SCAS is an electromechanical system that will automatically adjust the antenna shape by changing the length of control cords. Achieving and maintaining the proper surface shape and smoothness are critical to optimizing the electromagnetic characteristics of the antenna.

Ahl, Elvin L., Jr.↗
NASA NTRS2015

Survival Times of Meter-Sized Rock Boulders on the Surface of Airless Bodies

This study considers the survival times of meter-sized rock boulders on the surfaces of several airless bodies. As the starting point, we employ estimates of the survival times of such boulders on the surface of the Moon by[1], then discuss the role of destruction due to day-night temperature cycling, consider the meteorite bombardment environment on the considered bodies in terms of projectile flux and velocities and finally estimate the survival times. Survival times of meter-sized rocks on lunar surface: The survival times of hand specimen-sized rocks exposed to the lunar surface environment were estimated based on experiments modeling the destruction of rocks by meteorite impacts, combined with measurements of the lunar surface meteorite flux, (e.g.,[2]). For estimations of the survival times of meter-sized lunar boulders, [1] suggested a different approach based on analysis of the spatial density of boulders on the rims of small lunar craters of known absolute age. It was found that for a few million years, only a small fraction of the boulders ejected by cratering process are destroyed, for several tens of million years approx.50% are destroyed, and for 200-300 Ma, ~90 to 99% are destroyed. Following [2] and other works, [1] considered that the rocks are mostly destroyed by meteorite impacts. Destruction of rocks by thermal-stress. However, high diurnal temperature variations on the surface of the Moon and other airless bodies imply that thermal stresses may also be a cause of surface rock destruction. Delbo et al. [3] interpreted the observed presence of fine debris on the surface of small asteroids as due to thermal surface cycling. They stated that because of the very low gravity on the surface of these bodies, ejecta from meteorite impacts should leave the body, so formation there of fine debris has to be due to thermal cycling. Based on experiments on heating-cooling of cm-scale pieces of ordinary and carbonaceous chondrites and theoretical modeling of expansion of the cracks formed they concluded that thermal fragmentation breaks up rocks larger than a few centimeters more quickly than do micrometeoroid impacts. According to them at 1 AU distance from the Sun the lifetime of 10 cm rock fragments on asteroids with a period of rotation from 2.2 to 6 hours should be only ~103 to 104 years and the larger the rock the faster it gets destroyed. But although [3] are obviously correct stating that impact ejecta should leave small asteroids, the low-velocity part of escaping ejecta will mostly stay in orbits close this given asteroid and part of them will eventually return to it. Moreover, directly beneath the impact point the target rock should be fractured and crushed but may not leave the body (Figure 1). These two points question the conclusions of [3].

Basilevsky, A. T.↗
NASA NTRS2017

VHF SoOp (Signal of Opportunity) Technology Demonstration for Soil Moisture Measurement Using Microwave Hydraulic Boom Truck Platform

A goal of this research is to test deployable VHF antennas for 6U Cubesat platforms to enable validation of root zone soil moisture (RZSM) estimation algorithms for signal of opportunity (SoOp) remote sensing over the 240-270 MHz frequency band. The proposed work provides a strong foundation for establishing a technology development path for maturing a global direct surface soil moisture (SM) and RZSM measurement system over a variety of land covers. Knowledge of RZSM up to a depth of 1 meter and surface SM up to a depth of 0.05 meter on a global scale, at a spatial resolution of 1-10 km through moderate-to-heavy vegetation, is critical to understanding global water resources and the vertical moisture gradient in the Earths surface layer which controls moisture interactions between the soil, vegetation, and atmosphere. Current observations of surface SM from space by L-band radiometers (1.4 GHz) and radars (1.26 GHz) are limited to measurements of surface SM up to a depth of 0.05 meter through moderate amounts of vegetation. This limitation is mainly due to the inability of L-band signals to penetrate through dense vegetation and deep into the soil column. Satellite observations of the surface moisture conditions are coupled to sophisticated models which extrapolate the surface SM into the root zone, thus providing an indirect estimate rather than a direct measurement of RZSM. To overcome this limitation, low-frequency airborne radars operating at 435 MHz and 118 MHz have been investigated, since these lower frequencies should penetrate denser vegetation and respond to conditions deeper in the soil.

SoOp↗
NASA NTRS1975

Sea surface determination from space: The GSFC geoid

The determination of the sea surface/geoid and its relative variation were investigated and results of the altimeter experiment on Skylab to test the geoid are discussed. The spaceborne altimeter on Skylab revealed that the sea surface of the world's oceans can be measured with an accuracy in the meter range. Surface variations are discussed as they relate to those computed from satellite orbital dynamics and ground based gravity data. The GSFC geoid was constructed from about 400,000 satellite tracking data (range, range rate, angles) and about 20,000 ground gravity observations. One of the last experiments on Skylab was to measure and/or test this geoid over almost one orbit. It was found that the computed water surface deviates between 5 to 20 m from the measured one. Further outlined are the influence of orbital errors on the sea surface, and numerical examples are given based upon real tracking data. Orbital height error estimates were computed for geodetic type satellites and are found to be in the order of 0.2 to 5 meters.

Vonbun, F. O.↗
NASA NTRS2010

Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition on Kuiper Belt and Oort Cloud Bodies

The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environments. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Interactions of surface irradiation, resultant chemical oxidation, and near-surface cryogenic fluid reservoirs have been proposed to account for Enceladus cryovolcanism and may have further applications to other icy irradiated bodies. The diversity of causative processes must be understood to account for observationally apparent diversities of the object surfaces.

Cooper, John F.↗
NASA NTRS2010

Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition and Dynamics on Kuiper Belt and Oort Cloud Bodies

The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environment. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Cycles of atmospheric formation and surface freezeout can further account for temporal variation as observed on Pluto. The diversity of causative processes must therefore be understood to account for observationally apparent diversities of the object surfaces.

Cooper, John F.↗
NASA NTRSDate not supplied

Integral Equation Model of the Martian Surface layer for the Detection of Buried Ice Deposits in Support of the international Ice Mapping Mission Synthetic Aperture Radar

This work implemented a 3-D Electromagnetic Scattering model to gain a better understanding in the observations of L- and P-band radar returns from the multi-layered Martian upper surface layer. The model is based on the Integral Equation Model (IEM) developed by Adrian Fung. Our model implementation treats the upper surface (regolith) layer as an inhomogeneous medium with irregular boundaries for a range of Martian surface and shallow subsurface scenarios. The model is well suited to study the near subsurface (upper 10 meters of surface sediments) ice detection capability of the L-band (32 cm wavelength) Synthetic Aperture Radar (SAR) planned for the international Mars Ice Mapping (I-MIM) mission launching later in the 2020s.

surface roughness, Integral Equation Model (IEM)↗
NASA NTRS1986

Surface control system for the 15 meter hoop-column antenna

The 15-meter hoop-column antenna fabricated by the Harris Corporation under contract to the NASA Langley Research Center is described. The antenna is a deployable and restowable structure consisting of a central telescoping column, a 15-meter-diameter folding hoop, and a mesh reflector surface. The hoop is supported and positioned by 48 quartz cords attached to the column above the hoop, and by 24 graphite cords from the base of the antenna column. The RF reflective surface is a gold plated molybdenum wire mesh supported on a graphite cord truss structure which is attached between the hoop and the column. The surface contour is controlled by 96 graphite cords from the antenna base to the rear of the truss assembly. The antenna is actually a quadaperture reflector with each quadrant of the surface mesh shaped to produce an offset parabolic reflector. Results of near-field and structural tests are given. Controls structures and electromagnetics interaction, surface control system requirements, mesh control adjustment, surface control system actuator assembly, surface control system electronics, the system interface unit, and control stations are discussed.

Miller, James B.↗
NASA NTRS1980

Pioneer Venus radar results - Altimetry and surface properties

A topographic map of 93% of the Venus globe was depicted by the radar altimeter of the Pioneer Venus orbiter with a resolution better than 150 km. Extremes in relief expressed as a center-of-mass-to-surface radius extend from 6049 to 6062 km; the elevated terrain is dominated by a massive equatorial area equal in size to South America. The distribution of average meter-scale surface slopes is determined for the same regions in the 1 to 10 deg range; elevated areas have higher slopes, so that most features observed in the earth-based images are also evident in the vertical-incidence spacecraft measurements.

Pettengill, G. H.↗
NASA NTRS1995

Method of Making Large Area Nanostructures

A method which enables the high speed formation of nanostructures on large area surfaces is described. The method uses a super sub-micron beam writer (Supersebter). The Supersebter uses a large area multi-electrode (Spindt type emitter source) to produce multiple electron beams simultaneously scanned to form a pattern on a surface in an electron beam writer. A 100,000 x 100,000 array of electron point sources, demagnified in a long electron beam writer to simultaneously produce 10 billion nano-patterns on a 1 meter squared surface by multi-electron beam impact on a 1 cm squared surface of an insulating material is proposed.

Marks, Alvin M.↗
NASA NTRS2006

Cosmic Ray Mantle Visibility on Kuiper Belt Objects

Optically red objects constitute the dynamically cold, old component of the Classical Kuiper Belt (40 - 47 AU) with heliocentric orbits of low eccentricity and inclination. The red colors likely arise from primordial mixed ices processed by irradiation to meters in surface depth over the past four billion years, since the time of giant planet migration and Kuiper Belt stirring, at relatively moderate dosages of 60 gigarads provided by galactic cosmic ray protons and heavier ions. The red cosmic ray mantle is uniformly visible on the cold classical objects beneath a minimally thin eroded layer of more neutrally colored material arising from cumulative effects of heliospheric particle irradiation. The radiation fluxes are lowest in the middle heliospheric region containing the Classical Kuiper Belt and increase from there both towards and away from the Sun. Despite increasing irradiation at various times of solar system history from increases in solar and interstellar ion fluxes, the red object region has apparently never reached sufficiently high dosage levels to neutralize in color the red mantle material. Erosion processes, including plasma sputtering and micrometeroid impacts, act continuously to reduce thickness of the upper neutral crust and expose the cosmic ray mantle. A deeper layer at tens of meters and more may consist of relatively unprocessed ices that can erupt to the surface by larger impacts or cryovolcanism and account for brighter surfaces of larger objects such as 2003 UB313. Surface colors among the Kuiper Belt and other icy objects of the outer solar system are then a function, assuming uniform primordial composition, of relative thickness for the three layers and of the resurfacing age dependent on the orbital and impact history of each object.

Cooper, John F.↗
NASA NTRS2016

Quantifying Surface Water Dynamics at 30 Meter Spatial Resolution in the North American High Northern Latitudes 1991-2011

The availability of a dense time series of satellite observations at moderate (30 m) spatial resolution is enabling unprecedented opportunities for understanding ecosystems around the world. A time series of data from Landsat was used to generate a series of three maps at decadal time step to show how surface water has changed from 1991 to 2011 in the high northern latitudes of North America. Previous attempts to characterize the change in surface water in this region have been limited in either spatial or temporal resolution, or both. This series of maps was generated for the NASA Arctic and Boreal Vulnerability Experiment (ABoVE), which began in fall 2015. These maps show a nominal extent of surface water by using multiple observations to make a single map for each time step. This increases the confidence that any detected changes are related to climate or ecosystem changes not simply caused by short duration weather events such as flood or drought. The methods and comparison to other contemporary maps of the region are presented here. Initial verification results indicate 96% producer accuracy and 54% user accuracy when compared to 2-m resolution World View-2 data. All water bodies that were omitted were one Landsat pixel or smaller, hence below detection limits of the instrument.

Carroll, Mark↗