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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 NTRS2002

Biosensors for Real-Time Monitoring of Radiation-Induced Biologic Effects in Space

This proposal seeks to develop cellular biosensors based on dendritic polymers. Nanoscale polymer structures less than 20 nm in diameter will be used as the basis of the sensor/actuators. The structures will be designed to target into specific cells of an astronaut and be able to monitor health issues such as the exposure to radiation or infectious agents. Multiple components can be assembled on the polymers including target directors, analytical devices (such as molecular probes), magnetic particles and metals, and imaging agents. The design and assembly of these devices has been pioneered at the Center for Biologic Nanotechnology in the University of Michigan. These molecules would also be able to administer therapeutics in response to the needs of the astronaut, and act as actuators to remotely manipulate an astronaut as necessary to ensure their safety. The reporting will be accomplished either through fluorescence signal monitoring, with the use of multispectral analysis for signal interpretation, or through functional MRI. These nanosensors coupled to NEMS devices could facilitate the success and increase the safety of extended space flight.

Baker, James R., Jr.↗
NASA NTRS2005

Probing the Martian Subsurface with Synthetic Aperture Radar

Many regions of the martian surface are covered by fine-grained materials emplaced by volcanic, fluvial, or aeolian processes. These mantling deposits likely hide ancient channel systems (particularly at smaller scale lengths) and volcanic, impact, glacial, or shoreline features. Synthetic aperture radar (SAR) offers the capability to probe meters below the surface, with imaging resolution in the 10 s of m range, to reveal the buried terrain and enhance our understanding of Mars geologic and climate history. This presentation focuses on the practical applications of a Mars orbital SAR, methods for polarimetric and interferometric radar studies, and examples of such techniques for Mars-analog sites on the Moon and Earth.

Campbell, B. A.↗
NASA NTRS1996

Stable Lobed Mixer With Combustion Demonstrated and Measured

The NASA Lewis Research Center collaborated with the Massachusetts Institute of Technology (MIT) on an experiment to study the use of lobed mixers to improve the fuel-air mixing process and increase combustion intensity in combustors with minimal pressure loss. This experiment is the first known stable combusting flow studied for this device, and the data show a much faster and much more uniform combustion process than for flat-plate mixers. Several potential benefits may be realized from this study in future combustors, including a reduction in NO_x emissions because of the more uniform temperature distribution. The experiment was done in Lewis' Planar Reacting Shear Layer facility, which was adapted to accept a lobed mixer in addition to the original planar tip. A graduate student at MIT provided the mixer design concept, and Lewis provided the engineering, operations, and research expertise. The experiment used hydrogen-nitrogen mixtures to react with vitiated hot air at 920 K. A flow speed of about 120 m/sec and a speed ratio of 0.5 were used. Flow diagnostics consisted of traversing fine-wire thermocouples and pitot probes for flow mapping. Supplementary fluorescence images were taken with a charged coupled device (CCD) camera to show the location and temporal behavior of the reaction zone. The data showed that the lobed mixer consumed the reactants between 3 to 10 times faster than a corresponding planar shear layer. The figure shows the dramatic difference in the measured temperature distribution with and without the lobed mixer. The increased mixing rate was due to a larger interfacial area as well as to the secondary flow from the streamwise vortices off the tips of the lobes. In addition, the fluorescence images showed that the lobes acted as flame stabilizers.

Source record↗
NASA NTRS2006

An Assessment of NASA Glenn's Aeroacoustic Experimental and Predictive Capabilities for Installed Cooling Fans

Quiet, high performance electronics cooling fans are needed for both commercial applications and future manned space exploration missions. Researchers at NASA Glenn focusing on aircraft engine noise, have long been familiar with the challenge of reducing fan noise without sacrificing aerodynamic performance. Is it possible to capitalize on the lessons-learned in aircraft engine noise reduction to identify inexpensive ways to improve the aerodynamic and acoustic performance of electronics cooling fans? Recent tests at NASA Glenn have begun to look for answers to this question. The overall aerodynamic and acoustic performance of a commercially available, spaceflight qualified 80 mm diameter axial flow fan has been measured using an automated plenum in accordance with ISO 10302 in the hemi-anechoic chamber of NASA Glenn s Acoustical Testing Laboratory. These measurements are complemented by detailed aerodynamic measurements of the inlet, exhaust, and rotor wake regions of the fan using Particle Image Velocimetry and hot-wire probes. A study of preliminary results yielded recommendations for system designers, fan manufacturers, and researchers.

Koch, L. Danielle↗
NASA NTRS2006

System and method for improving ultrasound image acquisition and replication for repeatable measurements of vascular structures

High resolution B-mode ultrasound images of the common carotid artery are obtained with an ultrasound transducer using a standardized methodology. Subjects are supine with the head counter-rotated 45 degrees using a head pillow. The jugular vein and carotid artery are located and positioned in a vertical stacked orientation. The transducer is rotated 90 degrees around the centerline of the transverse image of the stacked structure to obtain a longitudinal image while maintaining the vessels in a stacked position. A computerized methodology assists operators to accurately replicate images obtained over several spaced-apart examinations. The methodology utilizes a split-screen display in which the arterial ultrasound image from an earlier examination is displayed on one side of the screen while a real-time live ultrasound image from a current examination is displayed next to the earlier image on the opposite side of the screen. By viewing both images, whether simultaneously or alternately, while manually adjusting the ultrasound transducer, an operator is able to bring into view the real-time image that best matches a selected image from the earlier ultrasound examination. Utilizing this methodology, measurement of vascular dimensions such as carotid arterial IMT and diameter, the coefficient of variation is substantially reduced to values approximating from about 1.0% to about 1.25%. All images contain anatomical landmarks for reproducing probe angulation, including visualization of the carotid bulb, stacking of the jugular vein above the carotid artery, and initial instrumentation settings, used at a baseline measurement are maintained during all follow-up examinations.

Selzer, Robert H.↗
NASA NTRS2012

On the Design of the Axel and DuAxel Rovers for Extreme Terrain Exploration

The solar system's most scientifically tantalizing terrain remains out of reach for traditional planetary rovers, which are typically limited to driving on slopes below 30 degrees. This paper details the design of a novel robotic explorer that would open access to these previously inaccessible locales, such as Martian crater walls where evidence of salty water was recently detected, Lunar polar craters where evidence of water ice was detected, and Lunar and Martian lava tubes for future habitability. The Axel rover is a two-wheeled robot capable of rappelling down steep (even vertical) slopes supported by a tether. The DuAxel rover is comprised of two Axel vehicles docked to a central module. Unrestricted by tether length, this four-wheeled system would be capable of driving long distances from a safe landing zone to the extreme terrain of interest. Once in the vicinity of terrain in which the tether would be required, one of the Axel rovers could undock from the central chassis and rappel downslope. The other Axel and central chassis would remain topside to act as an anchor and to provide line of site to Earth (for communications) and the Sun (for energy). As the detached Axel descends into the area of interest, it would receive power and relays data through conductors in its tether. Each Axel would carry a suite of instruments in a bay that would be tucked inside the wheels. Because of the novel configuration of Axel's major degrees of freedom, these instruments could be precisely pointed at targets at any desired downslope spatial separation. These instruments could then be deployed into close proximately to the ground by means of a simple mechanism, allowing for detailed study of the strata on the slope. Axel could accommodate a host of instruments, including a microscopic imager, infra-red spectrometers, thermal probes, and sample collection devices. This paper will describe the design of both the latest generation of Axel and DuAxel systems and their instrument/sampling mechanisms. Results from recent field trials at a rock quarry in California and a Martian analog site in the desert of Arizona will be described.

rover mobility↗
NASA NTRS1981

The planetary exploration programme after two decades

The possible future of the United States program of planetary exploration in the next two decades is examined. The scientific goals and strategy for the exploration of the solar system outside of the earth-moon system are outlined, and the increasing cost effectiveness (per bit of data returned) of the first two decades of space exploration is pointed out. Attention is then given to the next two missions which are currently authorized and under development, the Galileo Jupiter orbiter and descent probe mission and the International Solar Polar Mission, and to possible missions for the next two decades, which would require additional thrust capabilities, including cometary missions, the Venus Orbiting Imaging Radar mission, a follow-on solar probe mission, a Saturn-Titan dual probe, and a Mars sample return mission.

James, J. N.↗
NASA NTRS1989

An update of commercial infrared sensing and imaging instruments

A classification of infrared sensing instruments by type and application, listing commercially available instruments, from single point thermal probes to on-line control sensors, to high speed, high resolution imaging systems is given. A review of performance specifications follows, along with a discussion of typical thermographic display approaches utilized by various imager manufacturers. An update report on new instruments, new display techniques and newly introduced features of existing instruments is given.

Kaplan, Herbert↗
NASA NTRS1998

Here Comes Solar Prove!

Flying a trajectory perpendicular to the Earth-Sun line during its perihelion passage, Solar Probe will use in-situ and imaging instruments to provide the first three dimentional viewing of the corona, direct observations of solar polar regions, and local sampling of the solar environment. These primary observations are complemented by context-setting cruise measurements and Earth-based observations.

solar corona solar wind solar probe heliosphere ph↗
NASA NTRS2003

The Submillimeter Probe of the Evolution of Cosmic Structure (SPECS)

The NASA roadmap mission SPECS is conceived as an imaging and spectral interferometer that will have the sensitivity needed to reach back in time to the formation epoch of the first luminous objects, the angular resolution needed to image proto-planetary systems and galaxies at high redshift, and the spectral resolution needed to probe the physical conditions and measure the flows of interstellar gas in young galaxies, nascent stars, and the dust-enshrouded nuclei of galaxies that harbor massive black holes. With a 1 km maximum baseline and the capability to sample the u-v plane completely, SPECS will produce images with angular resolution 20 (lambda / 100 microns) mas over the wavelength range 40 less than lambda less than 800 microns. In this talk I will give the scientific motivation for SPECS, describe mission concepts and telescope measurement capabilities, and compare these capabilities with those of the next-generation IR telescopes, and with the complementary JWST and ALMA.

Leisawitz, David↗
NASA NTRS1990

Probing the tides in interacting galaxy pairs

Detailed spectroscopic and imaging observations of colliding elliptical galaxies revealed unmistakable diagnostic signatures of the tidal interactions. It is possible to compare both the distorted luminosity distributions and the disturbed internal rotation profiles with numerical simulations in order to model the strength of the tidal gravitational field acting within a given pair of galaxies. Using the best-fit numerical model, one can then measure directly the mass of a specific interacting binary system. This technique applies to individual pairs and therefore complements the classical methods of measuring the masses of galaxy pairs in well-defined statistical samples. The 'personalized' modeling of galaxy pairs also permits the derivation of each binary's orbit, spatial orientation, and interaction timescale. Similarly, one can probe the tides in less-detailed observations of disturbed galaxies in order to estimate some of the physical parameters for larger samples of interacting galaxy pairs. These parameters are useful inputs to the more universal problems of (1) the galaxy merger rate, (2) the strength and duration of the driving forces behind tidally stimulated phenomena (e.g., starbursts and maybe quasi steller objects), and (3) the identification of long-lived signatures of interaction/merger events.

Borne, Kirk D.↗
NASA NTRS2024

Dielectric Permittivity Measurements of Geologic Samples at Venus Surface Temperatures

Synthetic-aperture radar (SAR) and radar sounding are two powerful remote sensing techniques used to examine the surface and subsurface of planets. Their value is critical in the case of Venus due to this planet’s global and visually opaque cloud layer. The recently selected VERITAS and EnVision orbital missions, slated to study the planet in the early 2030’s, employ radar instruments to image the surface (VERITAS and EnVision) and probe the subsurface (EnVision). For both techniques, the complex dielectric permittivity of the surface and subsurface materials control radar backscatter intensity and penetration depth. Since the 1970’s, many studies have characterized the dielectric permittivity of geologic materials collected both on Earth and on the Moon to constrain the radar reflectivity and transparency at a variety of radar frequencies [e.g., 1]. Two consistent findings from those studies are that complex permittivity depends on both the density (or porosity) and the composition of the material. Denser materials and more metal-rich compositions tend to have higher permittivity values and to incur greater propagation path loss. Water content also elevates permittivity of otherwise dry rocks/soils/regolith [e.g., 2]. However, permittivity is independent of frequency for the 0.5-18 GHz range, within which SAR imaging commonly lies. The one aspect poorly explored thus far is the effect of elevated temperatures on dielectric permittivity. Previous work suggests that increased lattice vibrations and flow of free electrons associated with an increase in temperature elevate both the real (reflectivity) and imaginary (path loss) parts of the complex permittivity. We are currently conducting a 3-year campaign to measure the complex dielectric permittivity of Venusrelevant geologic materials at Venus surface temperatures (380°C - 460°C) and with frequencies relevant to VERITAS, EnVision, and Magellan imaging synthetic aperture radars.

M Barmatz↗
NASA NTRS1974

Planetary mission summaries. Volume 1: Introduction and overview

Tabular synopses of twelve missions are presented along with the Mariner Jupiter/Saturn 1977 mission for comparison. Mission definitions considered include: Mars Polar Orbiter; Mars Surface Sample Return; Mars Rover; Marine Jupiter/Uranus 1979 with Uranus Entry Probe; Mariner Jupiter Orbiter; Mariner Mercury Orbiter 1978; Early Mariner Comet Flyby Solar Electric Encke Slow Flyby; Mariner Encke Ballistic Flyby; Solar Electric Encke Rendezvous 1981; Venus Orbital Imaging Radar; Solar Electric Out-of-the-Eliptic Probe 1979. Technical conclusions of mission studies are given in order that these results may interact with the broader questions of scope, pace, and priorities in the planetary exploration program.

Source record↗
NASA NTRS2017

Chasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk

We have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST), using the newly commissioned BAR5 occulter. These HSTSTIS observations achieved an inner working angle of approximately 0 "2, or11.7 au, probing the system at angular radii coincident with recent images of the disk obtained by ALMA and in polarized intensity near-infrared light. By comparing our new STIS images to those taken with STIS in 2000 and with NICMOS in 1998, 2004, and 2005, we demonstrate that TW Hyas azimuthal surface brightness asymmetry moves coherently in position angle. Between 50 au and 141 au we measure a constant angular velocity in the azimuthal brightness asymmetry of 22.deg7 yr(exp -1) in a counterclockwise direction, equivalent to a period of 15.9yrassuming circular motion. Both the (short) inferred period and lack of radial dependence of the moving shadow pattern are inconsistent with Keplerian rotation at these disk radii. We hypothesize that the asymmetry arises from the fact that the disk interior to 1 au is inclined and precessing owing to a planetary companion, thus partially shadowing the outer disk. Further monitoring of this and other shadows on protoplanetary disks potentially opens anew avenue for indirectly observing the sites of planet formation.

protoplanetary disk orbiting TW Hya↗
NASA NTRSDate not supplied

Wind Tunnel PSD and MVD Characterization Using New 1D2D Optical Array Probes

This work explores characterization of the liquid clouds using a combination of a forward scattering probe and two Optical Array Probes. Current OAP probes provide particle shape, size, and number concentration from two-dimensional shadow images. However, past studies have shown that such images are subject to distortion when outside of the focal plane. This affects the retrieval of particle size distributions, particularly in the Supercooled Large Droplet size range. In this article, the use of a Droplet Measurement Technologies Cloud Droplet Probe and two new OAPs produced by Science Engineering Associates, is examined using wind tunnel data, to assess suitability for use in a wind tunnel calibration in SLD conditions. The new OAP probes exploit a flexible and simple grey scale imaging method to eliminate some present shortcomings of commonly used OAPs, and to reduce correction factors. Spinning disk measurements were used to specify probe depth of field, and average size errors. Composite spectra covering the nominal 2-3200 µm size range were formed by crossing over from the CDP to 1D2D-X at 48 µm, and then to the 1D2D-Y at about 400 µm. A good overlap was found at the crossover points without any artificial scaling. Composite spectra adequately closed the liquid water content distribution, and provided integrated LWCs within about 35% of the hot-wire LWCs used for tunnel calibration. This discrepancy was at least partially attributed to LWC underestimation by the hot-wire at high MVD. A model of probe performance was used to show an example of expected accuracy of ideal probes subject to the same OAP distortions and using the same mitigating procedures and corrections, predicting PSD Median Volume Diameter and integrated LWC errors of less than 10%.

Aircraft Icing↗
NASA NTRS2001

X-Ray Probes of Cosmic Star Formation History

We discuss the imprints left by a cosmological evolution of the star formation rate (SFR) on the evolution of X-ray luminosities Lx of normal galaxies, using the scheme earlier proposed by us, wherein the evolution of LX of a galaxy is driven by the evolution of its X-ray binary population. As indicated in our earlier work, the profile of Lx with redshift can both serve as a diagnostic probe of the SFR profile and constrain evolutionary models for X-ray binaries. We report here the first calculation of the expected evolution of X-ray luminosities of galaxies, updating our work by using a suite of more recently developed SFR profiles that span the currently plausible range. The first Chandra deep imaging results on Lx evolution are beginning to probe the SFR profile of bright spiral galaxies; the early results are consistent with predictions based on current SFR models. Using these new SFR profiles, the resolution of the "birthrate problem" of low-mass X-ray binaries and recycled, millisecond pulsars in terms of an evolving global SFR is more complete. We discuss the possible impact of the variations in the SFR profile of individual galaxies and galaxy types.

Ghosh, Pranab↗
NASA NTRS2005

Building the Case for SNAP: Creation of Multi-Band, Simulated Images With Shapelets

Dark energy has simultaneously been the most elusive and most important phenomenon in the shaping of the universe. A case for a proposed space-telescope called SNAP (SuperNova Acceleration Probe) is being built, a crucial component of which is image simulations. One method for this is "Shapelets," developed at Caltech. Shapelets form an orthonormal basis and are uniquely able to represent realistic space images and create new images based on real ones. Previously, simulations were created using the Hubble Deep Field (HDF) as a basis Set in one band. In this project, image simulations are created.using the 4 bands of the Hubble Ultra Deep Field (UDF) as a basis set. This provides a better basis for simulations because (1) the survey is deeper, (2) they have a higher resolution, and (3) this is a step closer to simulating the 9 bands of SNAP. Image simulations are achieved by detecting sources in the UDF, decomposing them into shapelets, tweaking their parameters in realistic ways, and recomposing them into new images. Morphological tests were also run to verify the realism of the simulations. They have a wide variety of uses, including the ability to create weak gravitational lensing simulations.

Ferry, Matthew A.↗