To appear at the AIAA Guidance, Navigation, and Control Conference
Monterey, California. 5 - 8 Aug 2002.

Abstract

Formation flying spacecraft has been identified as an enabling technology for many future NASA and DoD space missions. However, this is still, as yet, an unproven technology. Thus, to minimize the mission risk associated with these new formation flying technologies, testbeds are required that will enable comprehensive simulation and experimentation. This paper presents an innovative hardware-in-the-loop testbed for developing and testing estimation and control architectures for formation flying spacecraft. The testbed consists of multiple computers that each emulate a separate spacecraft in the fleet. These computers are restricted to communicate via serial cables to emulate the actual inter-spacecraft communications expected on-orbit. A unique feature of this testbed is that all estimation and control algorithms are implemented in Matlab, which greatly enhances its flexibility and reconfigurability and provides an excellent environment for rapidly comparing numerous control and estimation algorithms and architectures. A multi-tasking/multi-thread software environment is simulated by simultaneously running several instances of Matlab on each computer. The paper contains initial simulation results using one particular estimation, coordination, and control architecture for a fleet of 3 spacecraft, but current work is focused on extending that to larger fleets with different architectures. It is expected that this testbed will play a pivotal role in determining and validating the data flows and timing requirements for upcoming formation flying missions such as Orion and TechSat21.