Spare parts supply modelling: application to a space station

The work deals with the topic of spare parts management in a space system. The paper is divided into three parts. The first one is dedicated to the characterization of the system structure and presents the particularities related to the spare-elements procurement. Modelling is the object of the second part. After having exposed the bases of the problem to be solved, a macro-model is introduced. Each of the three elements of an orbital system, namely ground, flying and transport, is then described with a Petri net. Operation specificities of every element are then listed and integrated into the model. A concrete application of this modelling is given in the last part. It concerns the Columbus laboratory of the International Space Station. A representative function is selected and several supply strategies are evaluated

Gestion de l’approvisionnement initial en éléments de rechange d’un système orbital

Cet article présente une méthode de gestion de l’approvisionnement initial en pièces de rechange. Cette problématique générique revêt un intérêt particulier dans certains systèmes dont la difficulté d’accessibilité ou la durée de vie constitue des risques liés à des ruptures possibles de stock d’éléments de rechange. Nous considérons dans ce papier le cadre spatial. Après avoir commenté les particularités de la gestion des approvisionnements en éléments de rechange d’une station orbitale, nous proposons une méthode basée sur la minimisation du risque de report d’une opération de maintenance. Une application au laboratoire Colombus de la Station Spatiale Internationale est finalement présentée. This article presents a method of management of the initial supply spare parts. This generic problem is of a particular interest in certain systems whose difficulty of accessibility or lifespan constitutes risks related to possible stock of spare elements running out. We consider in this paper the space framework. After having commented on the characteristics of the management of the supplies elements of replacement of an orbiting station, we propose a method based on minimization of the risk of carry out of a maintenance action. An application to the Columbus laboratory of the International Space Station is finally presented

In-Situ rapid spares manufacturing and its application to human space missions

Maintaining the performance of logistically isolated systems yield serious support difficulties. In the perspective of a Human mission to Mars, it is known that the ability to maintain systems will be a key issue and that spare parts might pose some problems. Usual solutions consider improvements in reliability and fault-tolerance, storage of carefully selected parts, potential resupply missions, or a combination of these strategies. In this article, we propose a different approach. Having noted an analogy between physiology and the manufacture of parts, we consider the use of rapid-prototyping and manufacturing techniques to replace, on-site, a failed element by a palliative one, intended for temporary repairs or not. The system can then be restored to an acceptable level of performance so as to continue the mission, or wait for a more permanent repair. However interesting the concept is, some questions must be raised regarding technical feasibility, as well as reliability and safety impacts on the mission itself. The article is organised as follows. A first part describes briefly supply support methods and highlight their characteristics. A second part proposes and discusses the rapid spares manufacturing concept. The contribution of rapid prototyping techniques is evaluated in a third part and illustrated as an example. The last part indicates research perspectives linked with in-situ resources utilisation, as well as the qualification process for such spares

A SMART SAMPLING SCHEDULING AND SKIPPING SIMULATOR AND ITS EVALUATION ON REAL DATA SETS

International audienceAs modern manufacturing technology progresses, measurement tools become scarce resources since more and longer control operations are required. It thus becomes critical to decide whether a lot should be measured or not in order to get as much information as possible on production tools or processes, and to avoid ineffective measures. To minimize risks and optimize measurement capacity, a smart sampling algorithm has been proposed to efficiently select and schedule production lots on metrology tools. This algorithm and others have been embedded in a simulator called "Smart Sampling Scheduling and Skipping Simulator" (S5). The characteristics of the simulator will be presented. Simulations performed on several sets of instances from three different semiconductor manufacturing facilities (or fabs) will be presented and discussed. The results show that, by using smart sampling, it is possible to drastically reduce various performance indicators when compared to current fab sampling

Droit des successions

International audienceL’ouvrage traite chronologiquement les règles de dévolution, d’acquisition, de liquidation et de partage d’une succession. Tout en mettant l’accent sur l’essentiel, il donne de multiples pistes de réflexion sur l’application et l’avenir du droit actuel. Dans l’esprit de la collection « Thémis », il contient donc l’état des questions et les développements, non seulement proprement juridiques, mais aussi d’ordre historique et sociologique avec une ouverture importante vers le droit comparé

Droit des successions

International audienceL’ouvrage traite chronologiquement les règles de dévolution, d’acquisition, de liquidation et de partage d’une succession. Tout en mettant l’accent sur l’essentiel, il donne de multiples pistes de réflexion sur l’application et l’avenir du droit actuel. Dans l’esprit de la collection « Thémis », il contient donc l’état des questions et les développements, non seulement proprement juridiques, mais aussi d’ordre historique et sociologique avec une ouverture importante vers le droit comparé

Initial spare parts supply of an orbital system

International audienceThis article presents a method of management of the initial spare parts supply. This generic problem is of particular interest in certain systems in which the difficulty of accessibility or the life cycle duration constitute risks tied to the possible depletion of the spare parts stock. In this paper we consider the spatial context. After having commented on the particularities of the management of the spare parts supply of a space station, we propose a method based on the minimization of the risk of postponement of a maintenance operation. Finally, an application to the Columbus laboratory of the International Space Station is presented

In-Situ rapid spares manufacturing and its application to human space missions

International audienceMaintaining the performance of logistically isolated systems yield serious support difficulties. In the perspective of a Human mission to Mars, it is known that the ability to maintain systems will be a key issue and that spare parts might pose some problems. Usual solutions consider improvements in reliability and fault-tolerance, storage of carefully selected parts, potential resupply missions, or a combination of these strategies. In this article, we propose a different approach. Having noted an analogy between physiology and the manufacture of parts, we consider the use of rapid-prototyping and manufacturing techniques to replace, on-site, a failed element by a palliative one, intended for temporary repairs or not. The system can then be restored to an acceptable level of performance so as to continue the mission, or wait for a more permanent repair. However interesting the concept is, some questions must be raised regarding technical feasibility, as well as reliability and safety impacts on the mission itself. The article is organised as follows. A first part describes briefly supply support methods and highlight their characteristics. A second part proposes and discusses the rapid spares manufacturing concept. The contribution of rapid prototyping techniques is evaluated in a third part and illustrated as an example. The last part indicates research perspectives linked with in-situ resources utilisation, as well as the qualification process for such spares