Value chain · CLM-1106
In plain terms
The satellite's dark side charges to thousands of volts in the geostationary plasma, and the plastic backing of the solar cells would hold a few thousand volts across itself, within a factor of two of breaking down; the study's fix was a more conductive backing or a bleed path.
The claim as recorded
Rice's 1980 electrostatic study of the MSFC baseline satellite takes a worst-case GEO plasma of 2 per cm3 with "kTe = 5 keV and kTi = 10 keV", finds sunlit passive surfaces at 1 to 100 V positive from photoemission and dark-side passive surfaces near -17,000 V, and for the GaAlAs cell blanket (sapphire cover 20 um, kapton 25 um) computes "a drop of 949 V through the ion-attracting side, and a drop of 3.3 KV through the electron-attracting side", so that "In no case are the breakdown voltages exceeded" but "the voltage on the positive array is within a factor of 2 of the breakdown voltage" and at ten times the electron current "the voltage drop is 5.4 kV, which is near breakdown"; it therefore says "we recommend replacing kapton with a higher conductivity material, or else providing a current path from the solar cell to the back side", and expects no anomalous arcing at GEO because the ion currents are far below the 400 V threshold's current.
Evidence behind this: T3-university analysis for MSFC of the satellite's charging in the GEO plasma, on a stated worst-case environment; no test.
Scope and limits
NOT A RECTENNA DOCUMENT AND NOT VC07: Part I of the Rice contract is the satellite; Part II (SRC-564) is the rectenna. Worst-case plasma, steady state, secondaries neglected; the kapton resistivity law is Kennerud's 1974 measurement. Registered alongside the rectenna volumes it was read with; the layer assignment is provisional.
What it assumes
A thin-sheath approximation the study itself qualifies by Parker's PANEL results; the MSFC (Rockwell GaAlAs) baseline, not Boeing's silicon reference.
Where it comes from
PDF 5 / printed 4, raw: "our assumed" worst-case "plasma conditions are" N = 2/cm3, "kTe = 5 keV and kTi = 10 keV"; the -17,000 V dark-side potential from Chopra's equation and the 1 to 100 V positive sunlit potential are render readings of the same page; raw: "The sapphire coverglass is 20" um thick and "the kapton blanket is 25" um thick. PDF 6 / printed 5, normalised: "a drop of 949 V through the ion-attracting side, and a drop of 3.3 KV through the electron-attracting side"; "In no case are the breakdown voltages exceeded"; "the voltage on the positive array is within a factor of 2 of the breakdown voltage"; "the voltage drop is 5.4 kV, which is near breakdown"; "we recommend replacing kapton with a higher conductivity material, or else providing a current path from the solar cell to the back side"; "we do not anticipate anomalous arcing in the GEO environment".
Basis: volts of surface potential; kV across dielectric layers; A/cm2 of plasma and photoelectron current
Cite this
energyaperture.com/c/clm-1106
CLM-1106, Energy Aperture, as of 1980.