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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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17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Coaxial charged particle energy analyzer

A non-dispersive electrostatic energy analyzer for electrons and other charged particles having a generally coaxial structure of a sequentially arranged sections of an electrostatic lens to focus the beam through an iris and preferably including an ellipsoidally shaped input grid for collimating a wide acceptance beam from a charged-particle source, an electrostatic high-pass filter including a planar exit grid, and an electrostatic low-pass filter. The low-pass filter is configured to reflect low-energy particles back towards a charged particle detector located within the low-pass filter. Each section comprises multiple tubular or conical electrodes arranged about the central axis. The voltages on the lens are scanned to place a selected energy band of the accepted beam at a selected energy at the iris. Voltages on the high-pass and low-pass filters remain substantially fixed during the scan.

Kelly, Michael A.↗
NASA NTRS1975

ATS-6 - UCSD auroral particles experiment

The University of California at San Diego Auroral Particles Experiment aboard Applications Technology Satellite-6 (ATS-6) is discussed. The experiment is designed to investigate the time development of geomagnetic substorm particles, the confinement and loss of such particles, and the roles of plasma wave instabilities and characteristic system periodicities in substorm and general magnetospheric processes. The instrumentation includes a complement of five electrostatic charged particle detectors. Two detector assemblies are capable of rotation through 220 deg. The electrostatic curved plate energy/unit charge analyzers are ovoid, requiring particles to be bent only 55 deg to obtain azimuthal focusing. The inside of the plates is serrated to eliminate particles striking the sides. A post-analysis electrostatic lens consisting of two wire grids, one at the potential of the inner plate and one at the potential of ground, focuses particles strongly upon the center of the sensor. A spiraltron particle sensor detects the charged particles. The system has an energy range of five orders of magnitude with a lower extreme of less than 1 eV. Preliminary data are presented to illustrate phenomena which are observed as a result of the novel features described.

Mauk, B. H.↗
NASA NTRS1984

Improved Electrostatic Optical System

Device suitable for molecular epitaxial formation of semiconductor components. Improved electrostatic lens system uses cylindrical mirror as central element between two tubular lenses. Abberations introduced by mirror tend to cancel those introduced by tubular lenses. Result is order-of-magnitude improvement in chromatic or spherical compensation.

Lewis, B. F.↗
NASA NTRS1988

An electrostatically and a magnetically confined electron gun lens system

Focal properties, electron trajectory calculations, and geometries are given for two electron 'gun' lens systems that have a variety of applications in, for example, electron-neutral and electron-ion scattering experiments. One nine-lens system utilizes only electrostatic confinement and is capable of focusing electrons onto a fixed target with extremely small divergence angles, over a range of final energies 1-790 eV. The second gun lens system is a simpler three-lens system suitable for use in a uniform, solenoidal magnetic field. While the focusing properties of such a magnetically confined lens systenm are simpler to deal with, the system does illustrate features of electron extraction and Brillouin flow that have not been suitably emphasized in the literature.

Bernius, Mark T.↗
NASA NTRS2005

Promising Results from Three NASA SBIR Solar Array Technology Development Programs

Results from three NASA SBIR solar array technology programs are presented. The programs discussed are: 1) Thin Film Photovoltaic UltraFlex Solar Array; 2) Low Cost/Mass Electrostatically Clean Solar Array (ESCA); and 3) Stretched Lens Array SquareRigger (SLASR). The purpose of the Thin Film UltraFlex (TFUF) Program is to mature and validate the use of advanced flexible thin film photovoltaics blankets as the electrical subsystem element within an UltraFlex solar array structural system. In this program operational prototype flexible array segments, using United Solar amorphous silicon cells, are being manufactured and tested for the flight qualified UltraFlex structure. In addition, large size (e.g. 10 kW GEO) TFUF wing systems are being designed and analyzed. Thermal cycle and electrical test and analysis results from the TFUF program are presented. The purpose of the second program entitled, Low Cost/Mass Electrostatically Clean Solar Array (ESCA) System, is to develop an Electrostatically Clean Solar Array meeting NASA s design requirements and ready this technology for commercialization and use on the NASA MMS and GED missions. The ESCA designs developed use flight proven materials and processes to create a ESCA system that yields low cost, low mass, high reliability, high power density, and is adaptable to any cell type and coverglass thickness. All program objectives, which included developing specifications, creating ESCA concepts, concept analysis and trade studies, producing detailed designs of the most promising ESCA treatments, manufacturing ESCA demonstration panels, and LEO (2,000 cycles) and GEO (1,350 cycles) thermal cycling testing of the down-selected designs were successfully achieved. The purpose of the third program entitled, "High Power Platform for the Stretched Lens Array," is to develop an extremely lightweight, high efficiency, high power, high voltage, and low stowed volume solar array suitable for very high power (multi-kW to MW) applications. These objectives are achieved by combining two cutting edge technologies, the SquareRigger solar array structure and the Stretched Lens Array (SLA). The SLA SquareRigger solar array is termed SLASR. All program objectives, which included developing specifications, creating preliminary designs for a near-term SLASR, detailed structural, mass, power, and sizing analyses, fabrication and power testing of a functional flight-like SLASR solar blanket, were successfully achieved.

Eskenazi, Mike↗
NASA NTRS1968

Spacecraft control

Partial inertial system integration tests, automatic lens design, and vibration and shock analyses of electrostatic gyroscope

Source record↗
NASA NTRS2021

SMD Technology Highlights

Six technology highlights from the Science Mission Directorate (SMD) Heliophysics, Astrophysics, Earth, and Biological and Physical Sciences divisions. Technologies featured include 1. the 1653 m2 Solar Cruiser Solar Sail Propulsion system to enable missions to reach novel and otherwise difficult or impossible destinations for observing the Sun. 2. Technology sponsored by NASA and developed by MIT Space Nanotechnology Lab is developing high-performance space instrumentation for more powerful future X-ray telescopes that will study the dynamics of the high-energy universe. 3. Active thermal control technology that will help enable large ultra-stable telescopes needed to detect and characterize Earth-like planets around other stars. 4. SMD sponsored high-performance infrared sensors with reduced requirements for cooling onboard satellites and these sensors could potentially be flown on small satellite platforms like CubeSats. 5. A new technology that will utilize electron beams/ultraviolet light to remove dust that could help protect future space assets and astronauts from dangerous effects that arise from Moon/Mars dust exposure. 6. Studies using model organisms on ISS to understand the impact of the spaceflight environment on organisms in preparation for long-duration missions.

solar sail↗
NASA NTRS2016

Modeling a Miniaturized Scanning Electron Microscope Focusing Column - Lessons Learned in Electron Optics Simulation

This presentation discusses work done to assess the design of a focusing column in a miniaturized Scanning Electron Microscope (SEM) developed at the NASA Marshall Space Flight Center (MSFC) for use in-situ on the Moon-in particular for mineralogical analysis. The MSFC beam column design uses purely electrostatic fields for focusing, because of the severe constraints on mass and electrical power consumption imposed by the goals of lunar exploration and of spaceflight in general. The resolution of an SEM ultimately depends on the size of the focused spot of the scanning beam probe, for which the stated goal here is a diameter of 10 nanometers. Optical aberrations are the main challenge to this performance goal, because they blur the ideal geometrical optical image of the electron source, effectively widening the ideal spot size of the beam probe. In the present work the optical aberrations of the mini SEM focusing column were assessed using direct tracing of non-paraxial rays, as opposed to mathematical estimates of aberrations based on paraxial ray-traces. The geometrical ray-tracing employed here is completely analogous to ray-tracing as conventionally understood in the realm of photon optics, with the major difference being that in electron optics the lens is simply a smoothly varying electric field in vacuum, formed by precisely machined electrodes. Ray-tracing in this context, therefore, relies upon a model of the electrostatic field inside the focusing column to provide the mathematical description of the "lens" being traced. This work relied fundamentally on the boundary element method (BEM) for this electric field model. In carrying out this research the authors discovered that higher accuracy in the field model was essential if aberrations were to be reliably assessed using direct ray-tracing. This led to some work in testing alternative techniques for modeling the electrostatic field. Ultimately, the necessary accuracy was attained using a BEM/Fourier series hybrid approach. The presentation will give background remarks about the MSFC mini Lunar SEM concept and electron optics modeling, followed by a description of the alternate field modeling techniques that were tried, along with their incorporation into a ray-trace simulation. Next, the validation of this simulation against commercially available software will be discussed using an example lens as a test case. Then, the efficacy of aberration assessment using direct ray-tracing will be demonstrated, using this same validation case. The discussion will include practical error checks of the field solution. Finally, the ray-trace assessment of the MSFC mini Lunar SEM concept will be shown and discussed. The authors believe this presentation will be of general interest to practitioners of modeling and simulation, as well as those with a general optics background. Because electron optics and photon optics share many basic concepts (e.g., lenses, images, aberrations, etc.), the appeal of this presentation need not be restricted to just those interested in charged particle optics.

Modeling Miniaturizing Scanning↗
NASA NTRS1995

High-voltage space-plasma interactions measured on the PASP Plus test arrays

The Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) experiment was developed by the Air Force's Phillips Laboratory with support from NASA's Lewis Research Center. It was launched on the Advanced Photovoltaic and Electronics EXperiments (APEX) satellite on August 3, 1994 into a 70 degree inclination, 363 km by 2550 km elliptical orbit. This orbit allows the investigation of space plasma effects on high-voltage operation (leakage current at positive voltages and arcing at negative voltages) in the perigee region. PASP Plus is testing twelve solar arrays. There are four planar Si arrays: an old standard type (used as a reference), the large-cell Space Station Freedom (SSF) array, a thin 'APSA' array, and an amorphous Si array. Next are three GaAs on Ge planar arrays and three new material planar arrays, including InP and two multijunction types. Finally, there are two concentrator arrays: a reflective-focusing Mini-Cassegrainian and a Fresnel-lens focusing Mini-Dome. PASP Plus's diagnostic sensors include: Langmuir probe to measure plasma density, an electrostatic analyzer (ESA) to measure the 30 eV to 30 KeV electron/ion spectra and determine vehicle negative potential during positive biasing, and a transient pulse monitor (TPM) to characterize the arcs that occur during the negative biasing. Through positive biasing of its test arrays, PASP Plus investigated the snapover phenomenon, which took place over the range of +100 to +300 V. It was found that array configurations where the interconnects are shielded from the space plasma (i.e., the concentrators or arrays with 'wrap-through' connectors) have lower leakage current. The concentrators exhibited negligible leakage current over the whole range up to +500 V. In the case of two similar GaAs on Ge arrays, the one with 'wrap-through' connectors had lower leakage current than the one with conventional interconnects. Through negative biasing, PASP Plus investigated the arcing rates of its test arrays. The standard Si array, with its old construction (exposed rough-surface interconnects), arced significantly over a wide voltage and plasma-density range. The other arrays arced at very low rates, mostly at voltages greater than -350 V and plasma densities near or greater than 10(exp 5)/cm(exp -3). AS expected according to theory, arcing was more prevalent when array temperatures were cold (based on biasing in eclipse).

Guidice, Donald A.↗
NASA NTRS1992

Increased response of the reversal electron attachment detector and modeling of ion space-charge effects

Design and sensitivity tests of a modified version of the so-called reversal electron attachment detector (READ) are presented. The new version uses a spherical cathode capable of emitting higher electron currents. As in the original READ (which used a planar emitter) electrons are focused into an electrostatic mirror which reverses their trajectories. In the reversal region electrons have essentially zero energy and attach to target molecules to form negative ions. The electron gun lens system has been modified using a field and trajectory code with space charge included. Electron trajectories have been calculated for 1-mA current focused into a reversal region of 3.5-mm diameter. The detection limit of the apparatus is approximately 25 times lower than for the original READ. Nonlinearity in the measured signal vs electron current is described by a model in which a spherical ball of ions expands outward with velocity determined by the space-charge force and the initial velocity of ion formation.

Boumsellek, S.↗
NASA NTRS1976

Improved Einzel lenses

New insulator configuration simplifies construction of three-electrode electrostatic electron lenses in which center electrode is at high electrical potential. Spherical sapphire insulators are used in lieu of conventional tubular ceramic or plastic insulators in Einzel lens assembly.

Hart, R. K.↗
NASA NTRS1996

Directional electrostatic accretion process employing acoustic droplet formation

The present invention is directed to an apparatus for manufacturing a free standing solid metal part. In the present invention metal droplets are produced from a free surface pool of molten metal is when an acoustic wave impacts an acoustic lens that is contiguous with the free standing pool of molten metal. The metal droplets are then charged and deflected toward a target. The build up of the metal droplets combine to form the free standing solid metal part.

Oeftering, Richard C.↗
NASA NTRS1987

Generation of intense negative ion beams

An electron gun is used with a mirror electrostatic field to produce zero or near zero velocity electrons by forming a turning point in their trajectories. A gas capable of attaching zero or near zero velocity is introduced at this turning point, and negative ions are produced by the attachment or dissociative attachment process. Operation may be continuous or pulsed. Ions thus formed are extracted by a simple lens system and suitable biasing of grids.

Chutjian, Ara↗
NASA NTRS2003

NASA Tech Briefs, January 2003

Topics covered include: Optoelectronic Tool Adds Scale Marks to Photographic Images; Compact Interconnection Networks Based on Quantum Dots; Laterally Coupled Quantum-Dot Distributed-Feedback Lasers; Bit-Serial Adder Based on Quantum Dots; Stabilized Fiber-Optic Distribution of Reference Frequency; Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System; Ladar System Identifies Obstacles Partly Hidden by Grass; Survivable Failure Data Recorders for Spacecraft; Fiber-Optic Ammonia Sensors; Silicon Membrane Mirrors with Electrostatic Shape Actuators; Nanoscale Hot-Wire Probes for Boundary-Layer Flows; Theodolite with CCD Camera for Safe Measurement of Laser-Beam Pointing; Efficient Coupling of Lasers to Telescopes with Obscuration; Aligning Three Off-Axis Mirrors with Help of a DOE; Calibrating Laser Gas Measurements by Use of Natural CO2; Laser Ranging Simulation Program; Micro-Ball-Lens Optical Switch Driven by SMA Actuator; Evaluation of Charge Storage and Decay in Spacecraft Insulators; Alkaline Capacitors Based on Nitride Nanoparticles; Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells; Software for a GPS-Reflection Remote-Sensing System; Software for Building Models of 3D Objects via the Internet; "Virtual Cockpit Window" for a Windowless Aerospacecraft; CLARAty Functional-Layer Software; Java Library for Input and Output of Image Data and Metadata; Software for Estimating Costs of Testing Rocket Engines; Energy-Absorbing, Lightweight Wheels; Viscoelastic Vibration Dampers for Turbomachine Blades; Soft Landing of Spacecraft on Energy-Absorbing Self-Deployable Cushions; Pneumatically Actuated Miniature Peristaltic Vacuum Pumps; Miniature Gas-Turbine Power Generator; Pressure-Sensor Assembly Technique; Wafer-Level Membrane-Transfer Process for Fabricating MEMS; A Reactive-Ion Etch for Patterning Piezoelectric Thin Film; Wavelet-Based Real-Time Diagnosis of Complex Systems; Quantum Search in Hilbert Space; Analytic Method for Computing Instrument Pointing Jitter; and Semiselective Optoelectronic Sensors for Monitoring Microbes.

Source record↗
NASA NTRS1991

Inverse photoelectron spectrometer with magnetically focused electron gun

An inverse photoelectron spectrometer is described which is based on the design of a magnetically focused low energy electron gun. The magnetic lens extends its field over a relatively large segment of the electron trajectory, which could provide a better focusing effect on a high-current-density low-velocity electron beam, providing the magnetic field in the vicinity of the target is reduced sufficiently to preserve the collinearity of the beam. In order to prove the concept, ray tracing is conducted using the Herrmannsfeldt program for solving electron trajectories in electrostatic and magnetostatic focusing systems. The program allows the calculation of the angles of the electron trajectories with the z axis, at the target location. The results of the ray-tracing procedure conducted for this gun are discussed. Some of the advantages of the magnetic focusing are also discussed.

Krainsky, Isay L.↗
NASA NTRS1991

Sunmaster: An SEP cargo vehicle for Mars missions

Options are examined for an unmanned solar powered electric propulsion cargo vehicle for Mars missions. The 6 prime areas of study include: trajectory, propulsion system, power system, supporting structure, control system, and launch consideration. Optimization of the low thrust trajectory resulted in a total round trip mission time just under 4 years. The argon propelled electrostatic ion thruster system consists of seventeen 5 N engines and uses a specific impulse of 10,300 secs. At Earth, the system uses 13 engines to produce 60 N of thrust; at Mars, five engines are used, producing 25 N thrust. The thrust of the craft is varied between 60 N at Earth and 24 N at Mars due to reduced solar power available. Solar power is collected by a Fresnel lens concentrator system using a multistacked cell. This system provides 3.5 MW to the propulsion system after losses. Control and positioning to the craft are provided by a system of three double gimballed control moment gyros. Four shuttle 'C' launches will be used to transport the unassembled vehicle in modular units to low Earth orbit where it will be assembled using the Mobile Transporter of the Space Station Freedom.

Chiles, Aleasa↗