LANDSAT-D flight segment operations manual. Appendix B: OBC software operations

Abstract

The LANDSAT 4 satellite contains two NASA standard spacecraft computers and 65,536 words of memory. Onboard computer software is divided into flight executive and applications processors. Both applications processors and the flight executive use one or more of 67 system tables to obtain variables, constants, and software flags. Output from the software for monitoring operation is via 49 OBC telemetry reports subcommutated in the spacecraft telemetry. Information is provided about the flight software as it is used to control the various spacecraft operations and interpret operational OBC telemetry. Processor function descriptions, processor operation, software constraints, processor system tables, processor telemetry, and processor flow charts are presented.