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Volume Charge Distribution Measurement in Thin Dielectrics


TECHNOLOGY AREAS: Electronics, Space Platforms

OBJECTIVE:  Develop a Pulsed Electro-Acoustic or alternative technique to give volume charge distribution and electric fields within realistic spacecraft dielectric insulators at space-like radiation energies.

DESCRIPTION:  Pulsed Electro-Acoustic (PEA) techniques were developed to determine the internal charge distribution of high voltage power cable insulators after manufacturing. [1] By determining the volume charge distribution, the internal electric fields in a dielectric can be determined, allowing for better understanding of conditions leading to current leakage and dielectric breakdown. In the context of spacecraft charging and material selection, understanding of internal electric fields is essential to understanding the conditions capable of causing breakdown in a complex radiation environment. Multiple spacecraft have suffered anomalies or been disabled due to presumed dielectric discharge [e.g. 2]. The effects of dielectric discharge and prolonged electrostatic fields can change material properties over time. Understanding the internal charge distribution and charge carrier mobility in dielectrics can lead to material selection less sensitive to dielectric discharge and improved spacecraft materials. The current PEA methods lack the resolution required to determine the charge distribution in thin spacecraft dielectrics and at the relatively low incident energy of typical space plasma.

PHASE I:  Determine requirements for and design a vacuum-capable device with resolution to determine charge distributions in typical spacecraft materials at typical on-orbit radiation energies at a range of temperatures typical to orbit. Evaluate existing technology to identify components capable of providing the necessary resolution with modification.

PHASE II:  Construct a product capable of determining charge distributions in typical spacecraft materials at typical on-orbit radiation energies and perform tests on several common materials to provide a baseline of capabilities. Perform analysis of what is required to improve resolution and implement improvements if possible.


Military Application:  Provide material testing to determine spacecraft materials for use in hazardous environments, leading to longer spacecraft life and improved survivability and reliability during substorms and other space radiation hazards.

Commercial Application:  Generate improved data on dielectric charge distributions to improve material selection for spacecraft, thin electrical insulators on high voltage cables, and capacitors. Other uses may become apparent after continued use.

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