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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 NTRS2019

Jumping the Queue: From NASA to the Commercial Cloud

NASA's High-End Computing Capability (HECC) Project has made it possible for its users to run on commercial cloud resources in a seamless way. In the first of three phases, we implemented a pilot project for a few users, enabling them to “jump the queue” and burst jobs from the HECC environment to Amazon Web Services (AWS). By using GPU-accelerated nodes at AWS, the users were able to make significant advances in their research. The second phase of the project made AWS access available to all HECC users and added accounting to make users responsible for cloud charges. We are also enabling export-controlled work through the use of AWS GovCloud. In the third phase, we will add web-based mechanisms to permit non-HECC users to access cloud resources for their HPC projects.

Hood, Robert↗
NASA NTRS2003

Redox-Active Star Molecules Incorporating the 4-Benzolypyridinium Cation: Implications for the Charge Transfer Efficiency Along Branches versus Across the Perimeter in Dendrimers

We report the redox properties of four star systems incorporating the 4-benzoyl-N-alkylpyridinium cation; the redox potential varies along the branches, but remains constant at fixed radii. Voltammetric analysis (cyclic voltammetry and differential pulse voltammetry) shows that only two of the three redox-active centers in the perimeter are electrochemically accessible during potential sweeps as slow as 20 mV/s and as fast as 10 V/s. On the contrary, both redox centers of a branch are accessible electrochemically within the same time frame. These results are discussed in terms of slow through-space charge transfer and the globular 3-D folding of the molecules.

Yang, Jin-Hua↗
NASA NTRS1984

Observations of interplanetary energetic ion enhancements near magnetic sector boundaries

All the energetic medium-nuclei (carbon, nitrogen, and oxygen) flux increases observed by the satellites IMP 7 and IMP 8 at 1 AU during Bartels rotations 1906-1974 are examined. After removing flare-related increases, the remaining 145 events were compared to interplanetary-maganetic-field and solar-wind parameters. A class of flux enhancements is discovered in which the ion increases occur close to the onset of magnetic-sector boundary crossings. This observation is interpreted as a facilitated access to 1 AU of energetic ions from the corona or chromosphere via the magnetic-sector structure. It appears that this access is more significant for medium than for lighter nuclei, suggesting a possible charge or rigidity-dependent transport mechanism.

Briggs, P. R.↗
NASA NTRS2000

The ACCESS Mission: ISS Accommodation Study

ACCESS (Advanced Cosmic-ray Composition Experiment for Space Station) is a new mission concept payload for the International Space Station (ISS) which has undergone a preliminary accommodation study. ACCESS science goals include new measurements of the rare ultra-high energy and ultra-heavy components of the cosmic radiation above the Earth's atmosphere. The critical resource made available by the ISS is collecting power; up to 10,000 square meters-sr-days, for a four-year stay on-orbit, allows ACCESS to go beyond balloon-borne detectors. The instrument, consisting of a charge module, a transition radiation detector, and a calorimeter, measures nuclei throughout the periodic table. The study demonstrates that the ISS as a stable science platform at the threshold of space, can make improved cosmic-ray investigations possible in the next century.

Wefel, John P.↗
NASA NTRS1996

(abstract) Satellite Physical Oceanography Data Available From an EOSDIS Archive

The Physical Oceanography Distributed Active Archive Center (PO.DAAC) at the Jet Propulsion Laboratory archives and distributes data as part of the Earth Observing System Data and Information System (EOSDIS). Products available from JPL are largely satellite derived and include sea-surface height, surface-wind speed and vectors, integrated water vapor, atmospheric liquid water, sea-surface temperature, heat flux, and in-situ data as it pertains to satellite data. Much of the data is global and spans fourteen years.There is email access, a WWW site, product catalogs, and FTP capabilities. Data is free of charge.

oceanography Earth Observing System oceans data cl↗
NASA NTRS1980

A model for the formation and stabilization of charged water clathrates

A model for the formation and stabilization of charged water clathrates is presented which accounts for observed anomalies in H(+)(H2O)n ion distributions. These anomalies are observed in both ion cluster and neutral expansions and are consistent with the sizes expected for clathrate ions. That the same sizes are observed in both ion cluster and neutral expansions strongly suggests that a rapid ionic process is responsible for their formation. The proposed model is based on the high mobility and bonding effects of the excess proton in water. Computer simulations suggest that excess proton movement in a water clathrate would be suitable for stabilizing the clathrate structure as well as giving it access to a large number of nearly degenerate proton configurations. The formation of clathrates in charged water clusters of proper size can be ascribed to the following: rapid excess proton movement, a strong preference of the H3O(+) for a three-coordinate bonding structure (which is compatible with hydrogen bonding), and finally, relatively slow processes leading to thermal disorder.

Holland, P. M.↗
NASA NTRS1990

Space environment robot vision system

A prototype twin-camera stereo vision system for autonomous robots has been developed at Goddard Space Flight Center. Standard charge coupled device (CCD) imagers are interfaced with commercial frame buffers and direct memory access to a computer. The overlapping portions of the images are analyzed using photogrammetric techniques to obtain information about the position and orientation of objects in the scene. The camera head consists of two 510 x 492 x 8-bit CCD cameras mounted on individually adjustable mounts. The 16 mm efl lenses are designed for minimum geometric distortion. The cameras can be rotated in the pitch, roll, and yaw (pan angle) directions with respect to their optical axes. Calibration routines have been developed which automatically determine the lens focal lengths and pan angle between the two cameras. The calibration utilizes observations of a calibration structure with known geometry. Test results show the precision attainable is plus or minus 0.8 mm in range at 2 m distance using a camera separation of 171 mm. To demonstrate a task needed on Space Station Freedom, a target structure with a movable I beam was built. The camera head can autonomously direct actuators to dock the I-beam to another one so that they could be bolted together.

Wood, H. John↗
NASA NTRS1991

Multiple-Bit Errors Caused By Single Ions

Report describes experimental and computer-simulation study of multiple-bit errors caused by impingement of single energetic ions on 256-Kb dynamic random-access memory (DRAM) integrated circuit. Studies illustrate effects of different mechanisms for transport of charge from ion tracks to various elements of integrated circuits. Shows multiple-bit errors occur in two different types of clusters about ion tracks causing them.

Zoutendyk, John A.↗
NASA NTRS2004

Redox-Active Star Molecules Incorporating the 4-Benzoylpyridinium Cation - Implications for the Charge Transfer Along Branches vs. Across the Perimeter in Dendrimer

Dendrimers are self-repeating globular branched star molecules, whose fractal structure continues to fascinate, challenge, and inspire. Functional dendrimers may incorporate redox centers, and potential applications include antennae molecules for light harvesting, sensors, mediators, and artificial biomolecules. We report the synthesis and redox properties of four star systems incorporating the 4-benzoyl-N-alkylpyridinium cation; the redox potential varies along the branches but remains constant at fixed radii. Bulk electrolysis shows that at a semi-infinite time scale all redox centers are electrochemically accessible. However, voltammetric analysis (cyclic voltammetry and differential pulse voltammetry) shows that on1y two of the three redox-active centers in the perimeter are electrochemically accessible during potential sweeps as slow as 20 mV/s and as fast as 10 V/s. On the contrary, both redox centers along branches are accessible electrochemically within the same time frame. These results are explained in terms of slow through-space charge transfer and the globular 3-D folding of the molecules and are discussed in terms of their implications on the design of efficient redox functional dendrimers.

Leventis, Nicholas↗
NASA NTRS1986

Calculating Charge Transport in Semiconductors

Method, called flux method, improvement over conventional methods, easy to use, and applies in operating regime not accessible to conventional macroscopic methods. Key concept of flux method follows behavior of particle flux rather than concentration of particles. Method not subject to limitations that follow from local or infinitesimal analysis.

Byvik, C. E.↗
NASA NTRS2014

Evaluation of Magnetoresistive RAM for Space Applications

Magnetoresistive random-access memory (MRAM) is a non-volatile memory that exploits electronic spin, rather than charge, to store data. Instead of moving charge on and off a floating gate to alter the threshold voltage of a CMOS transistor (creating different bit states), MRAM uses magnetic fields to flip the polarization of a ferromagnetic material thus switching its resistance and bit state. These polarized states are immune to radiation-induced upset, thus making MRAM very attractive for space application. These magnetic memory elements also have infinite data retention and erase/program endurance. Presented here are results of reliability testing of two space-qualified MRAM products from Aeroflex and Honeywell.

Heidecker, Jason↗
NASA NTRS1993

Fault handling schemes in electronic systems with specific application to radiation tolerance and VLSI design

Naturally occurring space radiation particles can produce transient and permanent changes in the electrical properties of electronic devices and systems. In this work, the transient radiation effects on DRAM and CMOS SRAM were considered. In addition, the effect of total ionizing dose radiation of the switching times of CMOS logic gates were investigated. Effects of transient radiation on the column and cell of MOS dynamic memory cell was simulated using SPICE. It was found that the critical charge of the bitline was higher than that of the cell. In addition, the critical charge of the combined cell-bitline was found to be dependent on the gate voltage of the access transistor. In addition, the effect of total ionizing dose radiation on the switching times of CMOS logic gate was obtained. The results of this work indicate that, the rise time of CMOS logic gates increases, while the fall time decreases with an increase in total ionizing dose radiation. Also, by increasing the size of the P-channel transistor with respect to that of the N-channel transistor, the propagation delay of CMOS logic gate can be made to decrease with, or be independent of an increase in total ionizing dose radiation. Furthermore, a method was developed for replacing polysilicon feedback resistance of SRAMs with a switched capacitor network. A switched capacitor SRAM was implemented using MOS Technology. The critical change of the switched capacitor SRAM has a very large critical charge. The results of this work indicate that switched capacitor SRAM is a viable alternative to SRAM with polysilicon feedback resistance.

Attia, John Okyere↗
NASA NTRS1991

Saltation threshold detection in a wind tunnel by the measurement of the net electrostatic charge

The Mars surface wind tunnel (MARSWIT) is an open circuit wind tunnel used for aeolian studies and is located inside a large vacuum chamber allowing testing at Martian surface atmospheric pressure. Since direct access is not available to the tunnel during operation at low pressure, a remote method of saltation detection is needed. The bed is observed by means of closed circuit video, but it is often difficult to determine the initiation of threshold. The measurement by means of an electrometer of the net electric charge produced by the saltating particles has provided a reliable means of saltation threshold detection. Saltating particles become charged several ways, both in wind tunnels and in a natural environment. The most significant of these methods are tribo-charging and contact charging, which always occur. Fracture charging may also occur under the high velocities associated with particle transport on Mars or under simulated Martian conditions. Detection in MARSWIT is achieved by allowing the saltating particles to impinge on a planar conducting surface normal to the flow that is connected to ground through a Keithly electrometer. The signal from the electrometer is connected to a strip chart recorder along with the analog signal from the pitot tube transducer that is used to determine the wind velocity in the tunnel. Thus, a record of wind velocity and the initiation of particle saltation is conveniently displayed together. While both positive and negative charges are produced during saltation, this method measures only the net charge; thus the charge may be either positive or negative depending upon the particles being tested, the size and size distribution of the test material, and the wind velocity. This has proven to be a very trustworthy and sensitive method of saltation threshold detection, being especially useful with the smaller sized particles which are the most difficult to observe visually.

Leach, Rodman N.↗
NASA NTRS1994

Technology transfer initiatives

This report summarizes the University of Alabama in Huntsville (UAH) technology transfer activities with the Marshall Space Flight Center (MSFC) for the period of April 1993 through December 1993. Early in 1993, the MSFC/TUO and UAH conceived of the concept of developing stand-alone, integrated data packages on MSFC technology that would serve industrial needs previously determined to be critical. Furthermore, after reviewing over 500 problem statements received by MSFC, it became obvious that many of these requests could be satisfied by a standard type of response. As a result, UAH has developed two critical area response (CAR) packages: CFC (chlorofluorocarbon) replacements and modular manufacturing and simulation. Publicity included news releases, seminars, articles and conference papers. The Huntsville Chamber of Commerce established the Technology Transfer Subcommittee with the charge to identify approaches for the Chamber to assist its members, as well as non-members, access to the technologies at the federal laboratories in North Alabama. The Birmingham Chamber of Commerce has expressed interest in establishing a similar technology transfer program. This report concludes with a section containing a tabulation of the problem statements, including CAR packages, submitted to MSFC from January 1992 through December 1993.

Mccain, Wayne↗
NASA NTRS1977

The robot's eyes - Stereo vision system for automated scene analysis

Attention is given to the robot stereo vision system which maintains the image produced by solid-state detector television cameras in a dynamic random access memory called RAPID. The imaging hardware consists of sensors (two solid-state image arrays using a charge injection technique), a video-rate analog-to-digital converter, the RAPID memory, and various types of computer-controlled displays, and preprocessing equipment (for reflexive actions, processing aids, and object detection). The software is aimed at locating objects and transversibility. An object-tracking algorithm is discussed and it is noted that tracking speed is in the 50-75 pixels/s range.

Williams, D. S.↗
NASA NTRS2004

The Energy Spectra of Proton and Helium Measured from the ATIC Experiment

The Advanced Thin Ionization Calorimeter (ATIC) balloon experiment is designed to investigate the composition and energy spectra of cosmic rays at the highest energies currently accessible from direct measurements, the region up to 100 TeV. The instrument consists of a silicon matrix for charge measurement, a graphite target (0.75 nuclear interaction length) to induce hadronic fragmentation, 3 scintillator strip hodoscopes for triggering and helping reconstruct trajectory, and a BGO calorimeter (18 radiation lengths) to measure the energy of incident particles. ATIC had two successful Long Duration Balloon (LDB) flights from McMurdo, Antarctica: from 12/28/00 to 01/13/01 and from 12/29/02 to 01/18/03. We present the energy spectra of proton and helium extracted from the ATIC flights, over the energy range from 100 GeV to 100 TeV, and compare them with the results from other experiments at both the lower and higher energy ends.

Ahn, H. S.↗
NASA NTRS2013

MRAM Technology Status

Magnetoresistive Random Access Memory (MRAM) is much different from conventional types of memory like SRAM, DRAM, and Flash, where electric charge is used to store information. Instead of exploiting the charge of an electron, MRAM uses its spin to store data. This new type of electronics is known as "spintronics." The primary focus of this report is the current generation of MRAM technology, and its reliability, vendors, and space-readiness.

Heidecker, Jason↗
NASA NTRS2013

MRAM Technology Status

Magnetoresistive Random Access Memory (MRAM) is much different from conventional types of memory like SRAM, DRAM, and Flash, where electric charge is used to store information. Instead of exploiting the charge of an electron, MRAM uses its spin to store data. This new type of electronics is known as “spintronics.” The primary focus of this report is the current generation of MRAM technology, and its reliability, vendors, and space-readiness.

Heidecker, Jason↗