Optimal Modularity for Fractionated Spacecraft: The Case of System F6

In recent years, distributed and networked architecture has been suggested as a new approach to manage uncertainty, accommodate multiple stakeholders and increase scalability and evolvablity in spacecraft systems. This departure from monolithic rigid architectures provides the space systems with more flexibility and robustness in response to uncertainties that the system confronts during its lifetime. Distributed architecture, however, does not come with only advantages and can increase cost and complexity of the system and result in potential instabilities and undesired emergent behaviors. In this paper, we build a model using a configuration based on a simplified variation of System F6 architecture that is being developed as a part of a DARPA program on fractionated spacecraft. Using a modularity/fractionation decision framework, developed in our group, we calculate the net value that is gained (or lost) by moving from a monolithic to a fractionated architecture and show how the sign and magnitude of this value change as a function of uncertainties in the environment and various system parameters.