Validation of the NASCAP model using spaceflight data

The NASA Charging Analyzer Program (NASCAP) has been validated in a space environment. Data collected by the SCATHA spacecraft has been used with NASCAP to simulate the charging response of the spacecraft ground conductor and dielectric surfaces with considerable success. Charging of the spacecraft ground observed in eclipse, during moderate and severe substorm environments, and in sunlight has been reproduced using the code. Close agreement between both the currents and potentials measured by the SSPM's, and the NASCAP simulated response, has been obtained for differential charging. These comparisons with experiment and other independent tests of the features of the NASCAP physical model all support the conclusion that NASCAP is able to predict spacecraft charging behavior in a space environment. (Author)