Effects of Solar Array Shadowing on the Power Capability of the Interim Control Module

Abstract

The Interim Control Module (ICM) is being built by the US Naval Research Laboratory (NRL) for NASA as a propulsion module for the International Space Station (ISS). Originally developed as a spinning spacecraft used to move payloads to their final orbit, for ISS, the ICM will be in a fixed orientation and location for long periods resulting in substantial solar panel shadowing. This paper describes the methods used to determine the incident energy on the ICM solar panels and the power capability of the electric power system (EPS). Applying this methodology has resulted in analyses and assessments used to identify ICM early design changes/options, placement and orientations that enable successful operation of the EPS under a wide variety of anticipated conditions. Service module capabilities and enhance overall reliability. Phase 3 examined another option in which it would be placed on the US side of ISS. Here it would also augment the Service Module, but this placement would reduce interfaces between US and Russian elements. METHODS The assessment of ICM power capability was composed of two tasks: determination of the incident energy on NASA/TM-1999-209378 I 14. SUBJECT TERMS International Space Station: Electric power; Shadowing; Models 17. SECURITY CLASSIFICATION

Comparison of ISS power system telemetry with analytically derived data for shadowed cases

“…Prior papers have discussed the development of these tools (SPACE and its integrated shadowing algorithms) (Hojnicki, 1993) (Kerslake, 1993a) (Fincannon, 1996) and analysis results using them (Fincannon, 1995(Fincannon, , 1999(Fincannon, , 2002. SPACE models all required hardware and integrates all necessary analysis components to determine the time-varying effect of load demand on the power system.…”