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.