Real Time, Automatic Vehicle Potential Determination from ESA Measurements PDF Download

Author: Stanley L. Spiegel
Publisher:
ISBN:
Category : Electrostatic analyzers
Languages : en
Pages : 24

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Book Description
The problem of spacecraft charging at high altitudes is an important one for Air Force applications; indeed a major effort (SCATHA Project) has been undertaken to understand this phenomenon. Quite simply, when a space vehicle at geosynchronous orbit, interacting with its plasma environment, acquires a high negative potential (of the order of 1/2 kV), it is possible that onboard instrumentation will be damaged by electrical discharge between differentially charged surfaces of the spacecraft. Thus it is important to activate a discharge mechanism as soon as a dangerously high potential develops. This means it is necessay to have a reliable method of determining the real time vehicle potential, or more specifically, distinguishing whether or not the potential has reached or exceeded critical levels. An algorithm incorporating an onboard microprocessor to analyze data obtained by the vehicle, and determine the extent of charging, is desirable. Computational simplicity and speed are important considerations in the design of such an algorithm. Examination of data from the P78-2 satellite has indicated that electrostatic analyzer (ESA) ion count data, could serve as input to an algorithm designed to fulfill the aforementioned objectives. The development and testing of one such algorithm, referred to as the count ration algorithm, are described.