Migration to a distributed architecture for the Space Shuttle flight planning system

A system modeling approach was applied to the migration of Space Shuttle flight planning applications from a centralized computer to a distributed architecture. Four steps were performed in this approach: characterization of the current flight planning systems workloads, data and components: modeling of workload and usage on the current system; selection of a distributed architecture as candidate for migration; and modeling of projected workload and data resource utilization on the selected candidate architecture. Applying traditional system modeling steps for migration to a distributed system was instrumental in accurately predicting required system resources and significantly reducing risk in migration. Further, improvements in the distributed architecture were developed which would not have been possible without the knowledge gained during the system modeling process