Software for a system to control the trajectories of multiple spacecraft flying in formation is being developed to reflect underlying concepts of (1) a decentralized approach to guidance and control and (2) reconfigurability of the control system, including reconfigurability of the software and of control laws. The software is organized as a modular network of software tasks. The computational load for both determining relative trajectories and planning maneuvers is shared equally among all spacecraft in a cluster. The flexibility and robustness of the software are apparent in the fact that tasks can be added, removed, or replaced during flight. In a computational simulation of a representative formation- flying scenario, it was demonstrated that the following are among the services performed by the software:

  • Uploading of commands from a ground station and distribution of the commands among the spacecraft,
  • Autonomous initiation and reconfiguration of formations,
  • Autonomous formation of teams through negotiations among the spacecraft,
  • Working out details of high-level commands (e.g., shapes and sizes of geometrically complex formations),
  • Implementation of a distributed guidance law providing autonomous optimization and assignment of target states, and
  • Implementation of a decentralized, fuel-optimal, impulsive control law for planning maneuvers.

This work was done by Joseph B. Mueller of Princeton Satellite Systems, Inc. for Goddard Space Flight Center. For further information, access the Technical Support Package (TSP) free on-line at  under the Software category. GSC-14779-1