Plan management system for space science mission systems

Chaizy, P. A. and Dimbylow, T. G. and Hapgood, M. A. and Allan, P. M. (2009) Plan management system for space science mission systems. Advances in Space Research, 44 (1). pp. 1-22. ISSN 0273-1177

Abstract

The number and complexity of systems that control Space Science Missions continues to increase. As a result,it is desirable to improve the efficiency of these systems and, in particular, their performance and their productivity. In this paper, we set out a strategy to achieve this goal. In order to talk about improving the Performance and Productivity of a system we need to discuss the functional architecture of the system. In order to make progress, our strategy is to develop a generic methodology that decomposes the functional architecture of a Space Science Mission System and uses this decomposition to identify areas where improvements call be made. This paper concentrates oil the decomposition of one specific component, namely the Plan Management System. The purpose of the Plan Management System is to produce an operation plan that contains the directives that will operate the various nodes, i.e. physical parts, of the system such as the ground stations, the spacecraft, the instruments, or even human beings (when these are following specific instructions). In order to be generic, the decomposition of the Plan Management System must make no assumptions about the purpose and implementation choices that must ultimately be made. In order to describe a functional architecture, it must also make no assumptions about the nature and purpose of the nodes that the system will operate or the nodes on which it will run. In particular, it makes no assumptions as to whether the execution of the Plan Management System components is manual or automated or whether the functions will be executed oil the ground or in space. The methodology is based on the key points that more than one functional architecture call be used to satisfy a given set of system requirements and that a one-fit-for-all functional architecture is impossible to achieve (due to the variety of requirements). Therefore, in developing the methodology, we use theconcept of a Functional Architecture Module (FAM) to create the generic decomposition. The resulting Plan Management System architectures are constructed as an assembly of building blocks, the Functional Architecture Modules, which can call each other. We have identified seven modules of this kind. Specific requirements can allow, impose or forbid the use of particular modules so we discuss the criteria to decide whether a given module is relevant in a given Situation. This can help current and future mission planning system designers who may wish to use the FAMs, or something equivalent, to design the functional architecture of their system(s). In addition, we propose seven practical steps to improve the performance and productivity during the design, implementation and execution of the Plan Management System. Finally, we would like to stress that this methodology is far from being abstract and is currently being used to develop generic (in the sense given above) planning tools and procedures. Indeed, FAMs facilitate the separation of generic systems requirements from implementation choices/constraints. Such a separation prevents prescriptive design and implementation. Crown copyright (C) 2009 Published by Elsevier Ltd. on behalf of COSPAR. All rights reserved.