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Full-Text Articles in Physics

Electron Emission And Transport Properties Database For Spacecraft Charging Models, Phil Lundgreen Aug 2020

Electron Emission And Transport Properties Database For Spacecraft Charging Models, Phil Lundgreen

Theses and Dissertations

Modeling the rate and likelihood of spacecraft charging during spacecraft mission is critical to determine mission length, proposed spacec­raft attitude, and spacecraft design. The focus of this work is the creation and utilization of a database of secondary electron yield (SEY) measurements for a host of materials to increase accuracy in spacecraft modeling. Traditional methods of SEY data selection for input into spacecraft charging codes typically include the use of compiled materials databases incorporated in charging codes or selecting values from a specific scientific study. The SEY database allows users to select data inputs based upon the details associated with …


Secondary Electron Yield Measurements Of Carbon Nanotube Forests: Dependence On Morphology And Substrate, Brian Wood, Jordan Lee, Gregory Wilson, T. -C. Shen, Jr Dennison Aug 2019

Secondary Electron Yield Measurements Of Carbon Nanotube Forests: Dependence On Morphology And Substrate, Brian Wood, Jordan Lee, Gregory Wilson, T. -C. Shen, Jr Dennison

Journal Articles

Total, secondary, and backscatter electron yield data were taken with beam energies between 15 eV and 30 keV, in conjunction with energy emission data, to determine the extent of suppression of yield caused by carbon nanotube (CNT) forest coatings on substrates. CNT forests can potentially lower substrate yield due to both its inherently low-yield, low-atomic number (Z) carbon composition, and its bundled, high-aspect ratio structure. Rough surfaces, and in particular, surfaces with deep high-aspect-ratio voids, can suppress yields, as the electrons emitted from lower lying surfaces are recaptured by surface protrusions rather than escaping the near-surface region. Yields of multilayered …


Wireless Antenna Detection Of Electrostatic Discharge Events, Allen Andersen, Jr Dennison Aug 2019

Wireless Antenna Detection Of Electrostatic Discharge Events, Allen Andersen, Jr Dennison

Journal Articles

Wireless intraspacecraft communication technology is being developed for signal transfer on space missions to save weight and simplify the design. One consideration for this new technology is its interaction with space environmentinduced electrostatic discharges (ESDs). The short time scales of spacecraft ESD events result in broad frequency band signals that can interact with high-frequency wireless antennas. These interactions present a source of signal noise. However, they also present a possibility of in-flight wireless ESD monitoring. We present laboratory measurements of arcing on common spacecraft insulators using commercially available single-band 2.4-GHz and dual-band 2.4-/5.8-GHz Wi-Fi antennas. These wireless detections are shown …


An Enhanced Operational Definition Of Dielectric Breakdown For Dc Voltage Step-Up Tests, Allen Andersen, Jr Dennison Oct 2017

An Enhanced Operational Definition Of Dielectric Breakdown For Dc Voltage Step-Up Tests, Allen Andersen, Jr Dennison

Journal Articles

The imprecise definition of breakdown in the ASTM D3755-14 standard can misidentify breakdown. If the recommended test circuit current sensing element threshold is set too high, breakdown may occur undetected. Conversely, false positives may result from designating a low current threshold. An operational definition of breakdown much less sensitive to these pitfalls is outlined herein. This enhanced definition of breakdown is based on the average rate of change of the leakage current with increasing voltage, rather than a simple current threshold, avoiding ambiguous association with anomalies in current traces. For tests that continuously monitor leakage current, breakdown can be detected …


The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman Dec 2008

The Adaptability Of Langmuir Probes To The Pico-Satellite Regime, Andrew Jay Auman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to investigate whether it is feasible to use Langmuir probes on pico-satellites flying in low Earth orbit over mid- to low-latitude geographic regions. Following chapters on the expected ionospheric conditions and an overview of Langmuir probe theory, a chapter addressing the difficulties involved with pico-satellite Langmuir probes is presented. Also, the necessary satellite-to-probe surface area requirements in order to achieve confidence in pico-satellite Langmuir probe data, for the orbital regions of interest to this thesis, are stated.