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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 NTRS2006

Design of a Multi-Level/Analog Ferroelectric Memory Device

Increasing the memory density and utilizing the dove1 characteristics of ferroelectric devices is important in making ferroelectric memory devices more desirable to the consumer. This paper describes a design that allows multiple levels to be stored in a ferroelectric based memory cell. It can be used to store multiple bits or analog values in a high speed nonvolatile memory. The design utilizes the hysteresis characteristic of ferroelectric transistors to store an analog value in the memory cell. The design also compensates for the decay of the polarization of the ferroelectric material over time. This is done by utilizing a pair of ferroelectric transistors to store the data. One transistor is used as a reference to determine the amount of decay that has occurred since the pair was programmed. The second transistor stores the analog value as a polarization value between zero and saturated. The design allows digital data to be stored as multiple bits in each memory cell. The number of bits per cell that can be stored will vary with the decay rate of the ferroelectric transistors and the repeatability of polarization between transistors. It is predicted that each memory cell may be able to store 8 bits or more. The design is based on data taken from actual ferroelectric transistors. Although the circuit has not been fabricated, a prototype circuit is now under construction. The design of this circuit is different than multi-level FLASH or silicon transistor circuits. The differences between these types of circuits are described in this paper. This memory design will be useful because it allows higher memory density, compensates for the environmental and ferroelectric aging processes, allows analog values to be directly stored in memory, compensates for the thermal and radiation environments associated with space operations, and relies only on existing technologies.

MacLeod, Todd C.↗

NASA NTRS2023

Exploration of Design Drivers for the RVLT Lift+Cruise Reference Aircraft

A trade study was performed on an all-electric version of the Lift+Cruise urban air mobility reference aircraft developed under the Revolutionary Vertical Lift Technology Project. The trade study varied the input parameters of mission range, takeoff altitude, mission reserve time, cell specific energy, disk loading, and payload weight. A step-by-step incremental change in the input parameters was also examined. Analyses were performed using the NASA Design and Analysis of Rotorcraft tool and a Rapid Sizing Tool for electric vertical takeoff and landing aircraft. A comparison of the analysis results between the two tools shows good agreement in trends with differences in slope. Overall, the analysis shows that the Lift+Cruise configuration performs poorly on a NASA-defined, energy-dominated mission due to poor aerodynamic efficiency in forward flight. This poor cruise-flight efficiency results in a large energy requirement, which increases the required battery sizing and corresponding aircraft gross weight. As such, continued conceptual design and refinement of the Lift+Cruise reference aircraft by the RVLT Concepts Team will likely be limited.

UAM↗

NASA NTRS1982

Reduction of solar cell efficiency by bulk defects across the back-surface-field junction

The degradation of solar cell performance due to bulk defects distributed across the back-surface field junction is analyzed in terms of a three-region developed-perimeter model. Families of curves are computed and their physical significance is discussed in detail with reference to three parameters used to characterize the defects: defect area, defect density, and defect surface recombination velocity. A reduction in the open-circuit voltage due to the presence of a defect is expressed as a function of the defect area, density, cell thickness, and defect surface recombination velocity. Numerical examples are presented to illustrate the importance of the particular defect parameters.

Sah, C. T.↗

NASA NTRS1976

Solar cell array design handbook, volume 1

Twelve chapters discuss the following: historical developments, the environment and its effects, solar cells, solar cell filters and covers, solar cell and other electrical interconnections, blocking and shunt diodes, substrates and deployment mechanisms, material properties, design synthesis and optimization, design analysis, procurement, production and cost aspects, evaluation and test, orbital performance, and illustrative design examples. A comprehensive index permits rapid locating of desired topics. The handbook consists of two volumes: Volume 1 is of an expository nature while Volume 2 contains detailed design data in an appendix-like fashion. Volume 2 includes solar cell performance data, applicable unit conversion factors and physical constants, and mechanical, electrical, thermal optical, magnetic, and outgassing material properties. Extensive references are provided.

Rauschenbach, H. S.↗

NASA NTRS1980

Improved optics for an ultracentrifuge

Ultracentrifuge is important tool in study of polymers, biomolecules, and cell structures. In typical ultracentrifuge rotor supports pair of optically matched vials; one contains sample mixed in solvent, and other is reference that contains only solvent. Doubleslit optical system, transverse to rotor, creates interference pattern on photographic plate each time vials pass through optics. Medium in sample vial displaces interference maximums such that shift gives measurement of density distribution along length of sample.

Miller, C. G.↗

NASA NTRS1980

SPS silicon reference system

The design analysis of a silicon power conversion system for the solar power satellite (SPS) is summarized. The solar array, consisting of glass encapsulated 50 micrometer silicon solar cells, is described. The general scheme for power distribution to the array/antenna interface is described. Degradation by proton irradiation is considered. The interface between the solar array and the klystron equipped power transmitter is described.

Woodcock, G. R.↗

NASA NTRS1985

Observations of a monotectic solidification interface morphology

For detailed studies of the region around a solidification interface on a microscopic scale, a very thin (essentially two-dimensional) test cell may be translated across two temperature-controlled heating/cooling blocks and viewed with a microscope. Such a device is sometimes referred to as a temperature gradient microscope stage (TGS). Of particular interest in this study is the behavior of a monotectic type solution during solidification. Succinonitrile based model systems for metallic monotectic alloys, when solidified on a TGS, form an unusual 'worm-like' micromorphology. These interfaces are observable in situ under high optical magnification during growth.

Kaukler, W. F.↗

NASA NTRS1990

Systems analysis of Mars solar electric propulsion vehicles

Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented.

Hickman, J. M.↗

NASA NTRS1993

How do plant cell walls extend?

This article briefly summarizes recent work that identifies the biophysical and biochemical processes that give rise to the extension of plant cell walls. I begin with the biophysical notion of stress relaxation of the wall and follow with recent studies of wall enzymes thought to catalyze wall extension and relaxation. Readers should refer to detailed reviews for more comprehensive discussion of earlier literature (Taiz, 1984; Carpita and Gibeaut, 1993; Cosgrove, 1993).

Review, Tutorial↗

NASA NTRS1984

Electrochemistry and Storage

The term electrochemistry implies the use of devices that convert chemical energy into electrical energy and sometimes vice versa. These devices are usually composed of some number of individual cells that are connected together to form a battery. In the cases where these devices cannot be electrically recharged they are usually referred to as primary batteries, whereas if these batteries can be charged and recharged repeatedly, they are called secondary batteries. The past and present uses of primary and secondary batteries in aerospace applications are discussed.

Thaller, L. H.↗

NASA NTRS1990

Kingdom Animalia: the zoological malaise from a microbial perspective

Pain and cognitive dissonance abounds amongst biologists: the plant-animal, botany-zoology wound has nearly healed and the new gash--revealed by department and budget reorganizations--is "molecular" vs. "organismic" biology. Here I contend that resolution of these tensions within zoology requires that an autopoietic-gaian view replace a mechanical-neodarwinian perspective; in the interest of brevity and since many points have been discussed elsewhere, rather than develop detailed arguments I must make staccato statements and refer to a burgeoning literature. The first central concept is that animals, all organisms developing from blastular embryos, evolved from single protist cells that were unable to reproduce their undulipodia. The second points to the usefulness of recognizing the analogy between cyclically established symbioses and meiotic sexuality.

NASA Program Exobiology↗

NASA NTRSDate not supplied

Discerning Cell Surface Defects with 3D Optical Profilometry

This investigation seeks to establish better criteria that can be used for qualitative visual screening of cylindrical battery cells through exploration of various defects across multiple cylindrical Lithium-Ion battery cells. This investigation focuses on INR18650s and INR21700s cells from Molicel, LG, and Samsung. The principal instrument used is a high-definition 3D optical profilometer with measurement accuracy less than 0.5 microns. Through this effort, a catalog was built discerning minor surface imperfections from significant flaws. The catalog generated covers a comparison of axial and radial scratches, less than 5 microns, greater than 5 microns and greater than 15 microns, as well as the difference between surface discoloration, early-stage pitting, and late stages of corrosion. An exploration is made into cell button defects and crimp shoulder defects. When ultra-high-power optical magnification and three-dimension topological tools are not immediately available, this catalog will help determine if an individual cell is usable, worth further investigation, or failing. The purpose of this catalog is to be a field guide used for quick reference of a potential issue, with the goal of increasing screening throughput while reducing the need for costly examination. Trade names and trademarks are used in this abstract for identification only. Their usage does not constitute an official endorsement, either expressed or implied, by the National Aeronautics and Space Administration.

battery↗

NASA NTRSDate not supplied

Discerning Cell Surface Defects with 3D Optical Profilometry

battery↗

NASA NTRSDate not supplied

Government Reference Concept for a 10 kW Lunar South Pole Solar Array

Deployable and relocatable free-standing, solar arrays will be required for future lunar South Pole missions. Major design requirements for these arrays will be low mass, compact launch stowage, and highly reliable deployment and retraction performance. A novel conceptual design referred to as the Relocatable Solar Array (RSA) is presented fora 10 kW solar array to address these requirements. Simply stated, the concept is a pair of solar cell blankets freely hanging from a horizontal cross arm that is supported by a vertical slender telescoping mast, all of which, rests on a deployable tripod base. A major factor in simplifying this array is that the force exerted by lunar gravity is used to deploy and maintain the extension of the hanging array blankets. The other major factor in achieving the desired low mass and high volumetric efficiency is that the resulting array system operates in the vacuum, low-gravity, lunar environment with no deployed vibration frequency requirement. Such an environment enables the use of extraordinarily slender and low mass structural members to support the hanging array blankets. This concept was developed, in part, to serve as a NASA reference solar array concept against which other proposed arrays can be compared.

Space solar arrays, solar array structures, lunar ↗

NASA NTRS2010

[Characterization of Black and Dichothrix Cyanobacteria Based on the 16S Ribosomal RNA Gene Sequence]

My project focuses on characterizing different cyanobacteria in thrombolitic mats found on the island of Highborn Cay, Bahamas. Thrombolites are interesting ecosystems because of the ability of bacteria in these mats to remove carbon dioxide from the atmosphere and mineralize it as calcium carbonate. In the future they may be used as models to develop carbon sequestration technologies, which could be used as part of regenerative life systems in space. These thrombolitic communities are also significant because of their similarities to early communities of life on Earth. I targeted two cyanobacteria in my research, Dichothrix spp. and whatever black is, since they are believed to be important to carbon sequestration in these thrombolitic mats. The goal of my summer research project was to molecularly identify these two cyanobacteria. DNA was isolated from each organism through mat dissections and DNA extractions. I ran Polymerase Chain Reactions (PCR) to amplify the 16S ribosomal RNA (rRNA) gene in each cyanobacteria. This specific gene is found in almost all bacteria and is highly conserved, meaning any changes in the sequence are most likely due to evolution. As a result, the 16S rRNA gene can be used for bacterial identification of different species based on the sequence of their 16S rRNA gene. Since the exact sequence of the Dichothrix gene was unknown, I designed different primers that flanked the gene based on the known sequences from other taxonomically similar cyanobacteria. Once the 16S rRNA gene was amplified, I cloned the gene into specialized Escherichia coli cells and sent the gene products for sequencing. Once the sequence is obtained, it will be added to a genetic database for future reference to and classification of other Dichothrix sp.

Ortega, Maya↗

NASA NTRS2010

TERRA Battery Thermal Control Anomaly - Simulation and Corrective Actions

The TERRA spacecraft was launched in December 1999 from Vandenberg Air Force Base, becoming the flagship of NASA's Earth Observing System program to gather data on how the planet's processes create climate. Originally planned as a 5 year mission, it still provides valuable science data after nearly 10 years on orbit. On October 13th, 2009 at 16:23z following a routine inclination maneuver, TERRA experienced a battery cell failure and a simultaneous failure of several battery heater control circuits used to maintain cell temperatures and gradients within the battery. With several cells nearing the minimum survival temperature, preventing the electrolyte from freezing was the first priority. After several reset attempts and power cycling of the control electronics failed to reestablish control authority on the primary side of the controller, it was switched to the redundant side, but anomalous performance again prevented full heater control of the battery cells. As the investigation into the cause of the anomaly and corrective action continued, a battery thermal model was developed to be used in determining the control ability remaining and to simulate and assess corrective actions. Although no thermal model or detailed reference data of the battery was available, sufficient information was found to allow a simplified model to be constructed, correlated against pre-anomaly telemetry, and used to simulate the thermal behavior at several points after the anomaly. It was then used to simulate subsequent corrective actions to assess their impact on cell temperatures. This paper describes the rapid development of this thermal model, including correlation to flight data before and after the anomaly., along with a comparative assessment of the analysis results used to interpret the telemetry to determine the extent of damage to the thermal control hardware, with near-term corrective actions and long-term operations plan to overcome the anomaly.

Grob, Eric W.↗

NASA NTRS2015

BioSentinel: Mission Development of a Radiation Biosensor to Gauge DNA Damage and Repair Beyond Low Earth Orbit on a 6U Nanosatellite.

We are designing and developing a "6U" (10 x 22 x 34 cm; 14 kg) nanosatellite as a secondary payload to fly aboard NASA's Space Launch System (SLS) Exploration Mission (EM) 1, scheduled for launch in late 2017. For the first time in over forty years, direct experimental data from biological studies beyond low Earth orbit (LEO) will be obtained during BioSentinel's 12- to 18- month mission. BioSentinel will measure the damage and repair of DNA in a biological organism and allow us to compare that to information from onboard physical radiation sensors. In order to understand the relative contributions of the space environment's two dominant biological perturbations, reduced gravity and ionizing radiation, results from deep space will be directly compared to data obtained in LEO (on ISS) and on Earth. These data points will be available for validation of existing biological radiation damage and repair models, and for extrapolation to humans, to assist in mitigating risks during future long-term exploration missions beyond LEO. The BioSentinel Payload occupies 4U of the spacecraft and will utilize the monocellular eukaryotic organism Saccharomyces cerevisiae (yeast) to report DNA double-strand-break (DSB) events that result from ambient space radiation. DSB repair exhibits striking conservation of repair proteins from yeast to humans. Yeast was selected because of 1) its similarity to cells in higher organisms, 2) the well-established history of strains engineered to measure DSB repair, 3) its spaceflight heritage, and 4) the wealth of available ground and flight reference data. The S. cerevisiae flight strain will include engineered genetic defects to prevent growth and division until a radiation-induced DSB activates the yeast's DNA repair mechanisms. The triggered culture growth and metabolic activity directly indicate a DSB and its successful repair. The yeast will be carried in the dry state within the 1-atm P/L container in 18 separate fluidics cards with each card having 16 independent culture microwells, with integral microchannels and filters to supply nutrients and reagents, confine the yeast to the wells, and enable optical measurement. The measurement subsystem will monitor each subgroup of culture wells continuously for several weeks, optically tracking DSBtriggered cell growth and metabolism. BioSentinel will also include physical radiation sensors based on the TimePix sensor, as implemented by JSC's RadWorks group, which record individual radiation events including estimates of their linear-energytransfer (LET) values. Radiation-dose and LET data will be compared directly to the rate of DSB-and-repair events measured by the S. cerevisiae biosentinels. The spacecraft bus will operate in a deep space environment with functions that include command and data handling, communications, power generation (via deployable solar panels) and storage, and attitude determination-and-control system with micropropulsion. Development of the BioSentinel spacecraft will mature and prove multiple nanosatellite advances in order to function well beyond LEO: Communications from distances of ≥ 500,000 km; Autonomous attitude control, momentum management, and safe mode of nanosatellites in deep space; Shielding-, hardening-, design-, and software-derived radiation tolerance for electronics; Reliable functionality for 12 - 18 months of key subsystems for biofluidics, memory, communications, power, etc.; Close integration of living biological radiation event monitors with miniature physical radiation spectrometers; Biological measurement of solar particle events beyond Earth orbit In addition to providing the first biological results from beyond LEO in over 4 decades, BioSentinel will provide an adaptable small-satellite instrument platform to perform a range of human-exploration-relevant measurements that characterize the biological consequences of multiple outer space environments. BioSentinel is being developed under NASA's Advanced Exploration Systems program.

DNA damage↗

NASA NTRS2015

BioSentinel: Mission Development of a Radiation Biosensor to Gauge DNA Damage and Repair Beyond Low Earth Orbit on a 6U Nanosatellite

We are designing and developing a 6U (10 x 22 x 34 cm; 14 kg) nanosatellite as a secondary payload to fly aboard NASAs Space Launch System (SLS) Exploration Mission (EM) 1, scheduled for launch in late 2017. For the first time in over forty years, direct experimental data from biological studies beyond low Earth orbit (LEO) will be obtained during BioSentinels 12- to 18-month mission. BioSentinel will measure the damage and repair of DNA in a biological organism and allow us to compare that to information from onboard physical radiation sensors. In order to understand the relative contributions of the space environments two dominant biological perturbations, reduced gravity and ionizing radiation, results from deep space will be directly compared to data obtained in LEO (on ISS) and on Earth. These data points will be available for validation of existing biological radiation damage and repair models, and for extrapolation to humans, to assist in mitigating risks during future long-term exploration missions beyond LEO. The BioSentinel Payload occupies 4U of the spacecraft and will utilize the monocellular eukaryotic organism Saccharomyces cerevisiae (yeast) to report DNA double-strand-break (DSB) events that result from ambient space radiation. DSB repair exhibits striking conservation of repair proteins from yeast to humans. Yeast was selected because of 1) its similarity to cells in higher organisms, 2) the well-established history of strains engineered to measure DSB repair, 3) its spaceflight heritage, and 4) the wealth of available ground and flight reference data. The S. cerevisiae flight strain will include engineered genetic defects to prevent growth and division until a radiation-induced DSB activates the yeasts DNA repair mechanisms. The triggered culture growth and metabolic activity directly indicate a DSB and its successful repair. The yeast will be carried in the dry state within the 1-atm PL container in 18 separate fluidics cards with each card having 16 independent culture microwells, with integral microchannels and filters to supply nutrients and reagents, confine the yeast to the wells, and enable optical measurement. The measurement subsystem will monitor each subgroup of culture wells continuously for several weeks, optically tracking DSB-triggered cell growth and metabolism. BioSentinel will also include physical radiation sensors based on the TimePix sensor, as implemented by JSCs RadWorks group, which record individual radiation events including estimates of their linear-energy-transfer (LET) values. Radiation-dose and LET data will be compared directly to the rate of DSB-and-repair events measured by the S. cerevisiae biosentinels.

Radiation Biosensor↗