A critical overview on spacecraft charging mitigation methods

Abstract

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection Sl-.l?I°i'm',°";jr2'". '"i] Al SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) PERFORMING ORGANIZATION REPORT NUMBER AFRL-VS-HA-TR-2004-1073 SPONSOR/MONITOR'S ACRONYM{S) DISTRIBUTION/AVAILABILITY STATEMENT ABSTRACTInteractions between hazardous space plasmas and spacecraft surfaces often result in spacecraft charging. Spacecraft charging may disturb the scientific measurements onboard, affect communications, control, and operations of spacecraft, and may be harmfiil to the health of the elecronics on the spacecraft. Several mitigation methods have been proposed or tested in recent years. This paper presents a critical overview on all of the mitigation methods known to date: 1) passive emthods usmg sharp spikes and high secondary emission coefficient surface materials and 2) active methods using controlled emissions of electrons, ions, plasmas, neutral gas, and polar molecules. Paradoxically, emission of low-energy positive ions from a highly negatively charged spacecraft can reduce the chargmg level, because the ions tend to return and may generate secondary electrons which then escape. We discuss the advantages and disadvantages of each of the methods and illustrate the ideas by means of examples of results obtained on SCATHA and DSCS satellites. Finally, mitigation of deep dielectric charging is briefly discussed. Abstract-Interactions between hazardous space plasmas and spacecraft surfaces often result in spacecraft charging. Spacecraft charging may disturb the scientific measurements onboard, affect communications, control, and operations of spacecraft, and may be harmful to the health of the electronics on the spacecraft. Several mitigation methods have been proposed or tested in recent years. This paper presents a critical overvievf on all of the mitigation methods known to date: 1) passive methods using sharp spikes and high secondary emission coefficient surface materials and 2) active methods using controlled emissions of electrons, ions, plasmas, neutral gas, and polar molecules. Paradoxically, emission of low-energy positive ions from a highly negatively charged spacecraft can reduce the charging level, because the ions tend to return and may generate secondary electrons which then escape. We discuss the advantages and disadvantages of each of the methods and illustrate the ideas by means of examples of results obtained on SCATHA and DSCS satellites. Finally, mitigation of deep dielectric charing is briefly discussed. SUBJECT TERMS

The effects of vacuum ultraviolet radiation on low-k dielectric films

“…Surface-potential measurements, [49][50][51][52][53][54] obtained with a Kelvin probe, have been used for decades 55 as a technique for measuring charge induced on dielectric. Surfacepotential measurements can give useful information about the net charge deposited on and within the dielectric layer such as trapped charge, mobile (free) charge, and surface charge.…”

An Authorization Logic with Explicit Time

“…Two U.S. patents on mitigating surface charging were awarded Murad, 2002a, 2002b). As soon as the plasma is released, the potentials fall to near zero (Lai, 2003). _______________________________________________________________________…”

“…All known methods for mitigating spacecraft charging and discharging were summarized (Lai, 2003), with critical comments on each method. The advantages and disadvantages of each method are listed.…”

DC surface flashover characteristics of polyimide in vacuum under electron beam irradiation

“…PI material applied in spacecraft will induce surface and deep charging under the radiation of all kinds of charged particles in the space environment and finally trigger the electrostatic discharge phenomena of dielectric material. In the space environment with complex radiations, the surface flashover phenomenon in an extremely low dc electric field is a bottleneck problem for developing the spacecraft with high voltage and high power [2,3]. The academic circle has been attempting to reveal the mechanism of surface flashover performance of solid dielectric materials in vacuum through various kinds of methods.…”