Dynamic Logical Mission Modeling Tool

Justin A. Sadowski

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Abstract

The ability to test and evaluate spacecraft designs is limited by the challenges of getting to (and operating in) the mission environment, and thus modeling and simulation is one way the space industry drives down risk and assists development of new technologies. The more accurate these models and simulations become, the more useful they are to the designer. While there are many choices for orbital propagation software, there are not many that allow dynamic modeling of both the spacecraft (to include its mode states) and its interactions with the environment in which it operates. The environmental model includes the spacecraft's orbit and spatial relationship to other agents in the simulation as well as non-agent entities such as planets and stars. The in-house AFIT modeling and simulation software, the Logic-Based Mission Modeling Tool (LMMT), has introduced the capability of behavior-based modeling by defining the spacecraft's modes as logical states in a state machine, however, in its current form it does not allow for changes the satellite or other entities may make in how they interact with the environment in which it operates. This thesis research evaluates the usefulness of dynamic modeling as compared with static modeling (such as that which is already possible with the LMMT). When changes occur which make the spacecraft's method of interacting with the environmental model no longer relevant, due to either spacecraft mode changes or other agents in the simulation, the model should be dynamically updated to include these changes by means of repropagating the environmental model. This research's focus is to ideate and then evaluate a subset of use-cases that would create changes in the environmental model. Through this research, it is hoped to develop a method for identifying when a static model such as the LMMT should be utilized versus a dynamic model such as that developed specifically for this research.