Mission Concept for Autonomous on-orbit Assembly of a Large reflector in space
- Paper number
IAC-05-D1.4.03
- Author
Dr. Dario Izzo, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Dr. Mark Ayre, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Mr. Lorenzo Pettazzi, ZARM - University of Bremen, Germany
- Year
2005
- Abstract
Self organisation is the result of a set of dynamical mechanisms whereby structures appear at a global level due to the interactions amongst lower-level components. Self assembly can be considered a sub-domain of self organisation, where lower-level components actually form structures out of themselves rather than inert elements of the environment. Observing the instances of self-organisation and self-assembly widespread in nature we can marvel at the robustness of the processes and the complexity of the structures that are produced. The results achieved in this field can thus be used for the autonomous assembly of large structures in space. In particular in this paper the problem of the conceptual design of an assembly scheme for a large reflector is considered. Both ESA and NASA have identified several new mission concepts, including very large aperture telescopes and solar power collection and transmission systems, that require the construction of a large reflective surface in orbit. As long as the characteristic dimension of the reflector array is increasing the necessity of an in-situ assembly of different components by means of an automated procedure arises. The design criteria for the reflector array elements are identical to those for solar sails – low mass per unit area (high assembly loading), high specular reflectance (high sail efficiency), and stowability in a tight volume. Because of that in this paper the feasibility of reflector elements doubling as solar sails for a sailing transfer up to the reflector construction site from a lower orbit is investigated. Such a strategy could potentially reduce significantly the number of launches required to place a reflector array into position. The phase of the assembly process that requires proximity operation between several components can then be performed relying upon the novel techniques based on swarm intelligence. In particular, because of the fair maneuverability of solar sails, a master-slave configuration for the system architecture is here introduced. In this method only a small (optimised for the mission in hand) amount of agents belonging to the swarm has actuation capability (slaves). The slave elements can act to autonomously dock the array elements, and temporarily being their actuators. The coordination between the slaves is pursued according to an algorithm based upon two recently developed tools: the Transitional Rules Set method, and the Equilibrium Shaping technique. The transitional rules method allows description by a graph of a generic structure in space and is able to provide, at each assembly step, a set of rules that a swarm has to follow in order to build the target structure. The Equilibrium shaping technique is a novel autonomous guidance and control scheme for satellite swarm able to drive each docking procedure and allowing different groups of agents to navigate towards different formations in an autonomous way. As the construction of the system proceeds, the slaves would gradually embed themselves in the structure in order to provide the station keeping for the free-flying reflector. In this way it is apparent that the number of thrust units is potentially very much reduced. The essential features of the reflector assembly scheme proposed in this paper are then described and a brief description of the main issues related to the swarm components system design are discussed. In the end the advantage in term of number of launches required for the construction of a 10 Km diameter reflector array is displayed.
- Abstract document
- Manuscript document
IAC-05-D1.4.03.pdf (🔒 authorized access only).
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