Concepts and technology development for the autonomous assembly and reconfiguration of modular space systems

Abstract

This thesis will present concepts of modular space systems, including definitions and specific examples of how modularity has been incorporated into past and present space missions. In addition, it will present two architectures that utilize modularity in more detail to serve as examples of possible applications. The first example is a fully modular spacecraft design, which has standardized and reconfigurable components with multiple decoupled subsystems. This concept was developed into a testbed called Self-assembling Wireless Autonomous and Reconfigurable Modules (SWARM). This project sought to demonstrate the use of modular spacecraft in a laboratory environment, and to investigate the "cost," or penalty, of modularity. The second example investigates the on-orbit assembly of a segmented primary mirror, which is part of a large space-based telescope. The objective is to compare two methods for assembling the mirror. The first method uses a propellant-based spacecraft to move the segments from a central stowage stack to the mirror assembly. The second is an electromagnetic-based method that uses superconducting electromagnetic coils as a means of applying force and torque between two assembling vehicles to produce the same results as the propellant-based system.

(cont.) Fully modular systems could have the ability to autonomously assemble and reconfigure in space. This ability will certainly involve very complex rendezvous and docking maneuvers that will require advanced docking ports and sensors. To this end, this thesis investigates the history of docking ports, and presents a comprehensive list of functional requirements. It then describes the design and implementation of the Universal Docking Port (UDP). Lastly, it explores the development of an optical docking sensor called the Miniature Video Docking Sensor (MVDS), which uses a set of infrared LED's, a miniature CCD-based video camera, and an Extended Kalman Filter to determine the six relative degrees of freedom of two docking vehicles. It uses the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) to demonstrate this fully integrated docking system.