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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

An Analytic Model for Estimating the First Contact Resistance Needed to Avoid Damaging ESD During Spacecraft Docking in GEO

NASA’s Gateway program is to involve spacecraft (s/c) docking in the outer radiation belt in order to transfer Gateway elements between s/c for transport to lunar orbit. The charging of these s/c to different potentials prior to docking raises the possibility of a damaging electrostatic discharge (ESD) at the time of first contact between the s/c. A proposed mitigation strategy is for first contact to occur prior to docking through a resistor with resistance R that would lower the potential difference at an optimal rate to a sufficiently low value to prevent a damaging ESD. The coupling of s/c by a resistor can be modeled by SPIS (Spacecraft Plasma Interaction System), but for realistic two s/c models SPIS can take hours to simulate the evolution of the s/c surface charges and potentials to an equilibrium state. Our objective is to develop a simpler model of s/c resistive coupling that runs orders of magnitude faster while providing useful first design estimates of the time variation of the s/c potentials, current through the resistor, and how these vary with R and s/c configuration. This configuration is defined by the relative separation and orientation of the s/c, and their solar illumination. The configuration and geometry of the s/c determine their capacitive coupling. The s/c capacitances are computed using Nascap-2K. This abstract and the associated poster describe the first version of such a model, and initial tests.

Goodman, Michael L.↗
NASA NTRS1977

Common approach to solving SGEMP, DEMP, and ESD survivability

System Generated Electromagnetic Pulse (SGEMP) and Dispersed Electromagnetic Pulse DEMP) are nuclear generated spacecraft environments. Electrostatic discharge (ESD) is a natural spacecraft environment resulting from differential charging in magnetic substorms. All three phenomena, though differing in origin, result in the same problem to the spacecraft and that is Electromagnetic Interference (EMI). A common design approach utilizing a spacecraft structural Faraday Cage is presented which helps solve the EMI problem. Also, other system design techniques are discussed which minimize the magnitude of these environments through control of materials and electrical grounding configuration.

Ling, D.↗
NASA NTRS1977

Qualification model spacecraft tests for DEMP, SGEMP, and ESD effects

The development of a satellite design demonstration test program is described. The test approach is comprehensive in that it includes the effects from electrostatic discharge (ESD), system generated electromagnetic pulse (SGEMP), as well as dispersed electromagnetic pulses (DEMP). The comprehensive test concept is based on the similarity of the satellite's response to several environments.

Chivington, E. P.↗
NASA NTRS1992

Quantitative ESD Guidelines for Charged Spacecraft Derived from the Physics of Discharges

Quantitative guidelines are proposed for Electrostatic Discharge (ESD) pulse shape on charged spacecraft. The guidelines are based on existing ground test data, and on a physical description of the pulsed discharge process. The guidelines are designed to predict pulse shape for surface charging and internal charging on a wide variety of spacecraft structures. The pulses depend on the area of the sample, its capacitance to ground, and the strength of the electric field in the vacuum adjacent to the charged surface. By knowing the pulse shape, current vs. time, one can determine if nearby circuits are threatened by the pulse. The quantitative guidelines might be used to estimate the level of threat to an existing spacecraft, or to redesign a spacecraft to reduce its pulses to a known safe level. The experiments which provide the data and the physics that allow one to interpret the data will be discussed, culminating in examples of how to predict pulse shape/size. This method has been used, but not confirmed, on several spacecraft.

Frederickson, A. R.↗
NASA NTRS2009

NASA Workmanship Hot Topics: Water Soluble Flux and ESD Charge Device Model

This slide presentation reviews two topics of interest to NASA Workmanship: (1) Water Soluble Flux (WSF) and Electrostatic Discharge (ESD) safety. In the first topic, WSF, the presentation reviews voiding and the importance of cleanliness in using WSF for welding and soldering operations. The second topic reviews the NASA-HDBK-8739.21 for Human Body Model, and Machine Model safety methods, and challenges associated with the Charged Device Model (CDM)

Plante, Jeannette F.↗
NASA NTRS2014

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 μs to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

Wright, K. H.↗
NASA NTRS2015

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micros to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

Wright, Kenneth H., Jr.↗
NASA NTRS2019

Revision of Paschen's Law Relating to the ESD of Aerospace Vehicle Surfaces

The purpose of this work is to develop a form of Paschen's law that takes into account the flow of gas past electrode surfaces. This work was performed under a NASA Science Innovation Fund (SIF) project at the Kennedy Space Center in collaboration with the University of Central Florida. In 2010 the Electrostatics and Surface Physics Laboratory (ESPL) at the Kennedy Space Center performed an electrostatic safety analysis on the flight termination system (FTS) antenna for the Ares I rocket. Paschen's law, derived by Friedrich Paschen in 1889 to relate sparking voltage to gas pressure and electrode separation, does not take into account the effect of flowing gas between the electrodes. The safety of the FTS housing to triboelectric charging was shown only after extensive laboratory testing. Potential benefits are of a form of Paschen's law that considers gas velocity. This work is applicable to current and planned rockets and aerospace vehicles and could lead to possible relaxation of electrostatic launch criteria. Launch aborts can cost up to about a million US dollars depending on the vehicle. [ElectroStatic Discharge (ESD)]

Paschen↗
NASA NTRS2020

An Experimental Validation of a Revised Paschen's Law Relating to the ESD of Aerospace Vehicle Surfaces

This work seeks to experimentally validate a modified Paschen law which takes into account the effects of electron-ion pair removal between two electrodes within a dynamic gas medium. A test facility has been designed and fabricated in order to create supersonic flow conditions within the test section. Custom designed electrodes are mounted into the test section at desired gap distances. A power supply is utilized to charge the electrodes until discharge occurs. The discharge voltage of the electrode is recorded over a range of pressures within the test section. An operational pressure range is calculated using isentropic flow and normal shock relations at the desired Mach numbers. These values are plotted against the modified Paschen curve as a function of Mach number, electrode gap distance, and pressure as a means of validation.

ESD↗
DOE OSTI2025

ESD: Ethernet Signal Differentiator [Poster]

Can Machine Learning Algorithms be trained to interpret and decode passively observed Automative Ethernet full-duplex signals without access to the original signals transmitted by either endpoint?

97 - MATHEMATICS AND COMPUTING↗
NASA NTRS1977

Status of the Electroforming Shield Design (ESD) project

The utilization of a digital computer to augment electrodeposition/electroforming processes in which nonconducting shielding controls local cathodic current distribution is reported. The primary underlying philosophy of the physics of electrodeposition was presented. The technical approach taken to analytically simulate electrolytic tank variables was also included. A FORTRAN computer program has been developed and implemented. The program utilized finite element techniques and electrostatic theory to simulate electropotential fields and ionic transport.

Fletcher, R. E.↗
NASA NTRS1992

Report of investigations into charge cadmium reactivity: Nickel-cadmium cell ESD 91-86

In Aug. 1990, a presentation was given at the 25th Ann. IECEC meeting on the results of Destructive Physical Analysis (DPA) on two successive sets of Ni-Cd cells. The cells were of two different separator types, Pellon 2505 and 2536. One cell of each separator type was analyzed on two occasions; the first pair were analyzed to establish baseline data on essentially new cells; the second pair were analyzed after the cells had been on charge-discharge cycling for a year in connection with a satellite simulation study. The gas composition found in the cells, the absence of charged cadmium in the analytical data, and the appearance of dried out portions on the Cd plates in the one year cell S/N 7 which used Pellon 2505 as its separator material, were questions which arose. These concerns are answered and the observational results are clarified.

Lewis, Harlan L.↗
NASA NTRS1999

Electrostatic Discharge (ESD) Failures in Thin Film Resistors

Field failures of nichrome thin film resistors have been investigated recently for several pieces of space flight hardware. These failures have involved resistance shifts ranging from a few percent to complete open circuits. Failure analysis and duplication of these failures have revealed that the failures were caused by electrostatic discharge. The failure characteristics and the circuit conditions necessary for failure have been studied for several types of thin film resistors including nichrome and tantalum nitride resistive elements. The effects of latent damage and resistive pattern design will also be discussed.

Hull, Scott M.↗