Asynchronous Multiphysics for Spacecraft System Modeling and Simulation

For space missions, modeling of simultaneous physical effects (multiphysics) on the consumable resources of a spacecraft or habitat is important for early iteration on mission design and operations feasibility. These simultaneous physical effects may cause issues like toxic gas buildup, overheating, or cascading power failures that are only possible to predict using an integrated simulation of a whole spacecraft. Long duration missions may depend on this modeling for accurate prediction of usage rate of consumables and sizing requirements for spacecraft systems.In most spacecraft design efforts, high fidelity modeling of multiphysics such as simultaneous heat transfer and off-gassing is done at the component level with expensive and specialized software. Integrated simulation of the whole spacecraft is typically done by piecing together tabulated performance data from each component, which has some possibilities for missing effects from component-to-component interactions. In order to do multiphysics modeling for arbitrary spacecraft configurations in a real-time simulation with continuously varying environmental conditions, this research develops a novel simulation architecture.SimDynamX LLC and the Texas A&M ASTRO Lab have been developing Space Teams, an engineering design and simulation platform for space missions. Within Space Teams, all objects in a simulation are Entities, and they may be connected by Edges using a graph structure representation, with each Entity constituting a Node. This graph structure can change dynamically according to events that occur within the wider simulation, such as a spacecraft docking or a hatch being closed. A system of graph network algorithms are used to provide a programming framework for modeling simultaneous flow of mass and energy between Nodes. This is split into Solvers, which compute instantaneous rates from physical effects (e.g. heat conduction in Watts or fluid flow in kg/s), and Integrators which evolve the simulation forward in time, maintaining conservation laws and updating the state of the nodes. Solvers are specific to one process, such as blackbody radiation, and Integrators are specific to one type of resource quantity, such as temperature, oxygen or power.In this paper, we describe the novel architecture of Space Teams' Advanced Resource Flow system, and compare its capabilities to other multiphysics software.