Abstract : Users often work directly with a collection of legacy simulation programs. These users are responsible for producing the input files for these programs, executing them, and managing their results. This project is to design and construct a general-purpose environment to support this process. In particular, we explore how to base this environment on an explicit object-oriented domain model that describes the domain actions that are simulated by existing simulation programs and the domain objects that are provided as input to or generated as output from these programs. The goal is to demonstrate that it is both possible and beneficial to construct an environment through which users interact with legacy simulation programs solely through an explicit domain model. This report describes the general architecture of such an environment and provides detailed examples that show how this environment can be applied to support users working with a collection of programs that simulate the formation and orbit of space debris.