Revisiting Solar Array String Failures on the International Space Station

Abstract

The main truss solar arrays of the International Space Station (ISS) have been providing electrical power to the spacecraft for multiple decades. As the solar arrays age, strings on the solar arrays may completely lose functionality, causing a drop in power generation of around 300W. Performance of the solar array strings is periodically checked to identify failed circuitry. Previous presentations on this topic introduced the techniques used to identify solar array string failures and a survey of the ISS to identify the string failures. Since the latest presentation, some of these techniques have declined in usefulness. The installation of the new ISS Roll-Out Solar Arrays (IROSA) and other events in space have had an impact on the string failures. This presentation will review the techniques to identify solar array string failures on the ISS and provide an updated survey of failed strings to date.