Verification and Validation of the Comprehensive Operational Support EvaluationModel for Space

摘要

This study details the verification and validation (V and V) of the ComprehensiveOperational Support Evaluation Model for Space (COSEMS). COSEMS is an Ada-based simulation which models spacecraft constellation support concepts such as support from the ground and on-orbit support. While the model is intended for use in analyzing Strategic Defense System concepts, it can easily evaluate non-military satellite constellations. The VV was confined to a subset of the over 200 subprograms which comprise COSEMS. This subset covered random number generation, reliability, orbital mechanics, and mission planning functions. The study used traces and comparison to other models to perform the VV. An input/output analysis was also performed to ascertain the ease of use of COSEMS and the utility of its output. The analysis showed that the areas under investigation performed according to the model and that the model approximated real-world behavior except for orbital motion. The part of the model governing orbital perturbations due to the non-spherical earth omitted rotation of the line-of-apsides. The analysis also revealed that the Ada code and the input/output format are highly machine dependent, which restricts the program from coming into widespread use and limits the usefulness of the output.