In many cases, the training and decision support needs of military users are urgent; operations cannot wait and missions have to be accomplished. Simulators, wargames scenarios and experiments should be ready 'yesterday'. New kinds of operations, environments, tactics, equipment and force configurations challenge our simulation capacities. To mitigate the cost impact and meet the time sensitive requirements, the M&S community has to be 'ready in advance'. This objective may be brought nearer by reusing resources that have been previously developed, possibly by external organizations, and reconfiguring and assembling these resources according to the current needs. Today, more than ever, warfighting excellence is related to the level of reusability of M&S resources. The NATO Modelling and Simulation Task Group MSG-042 (part of the NATO Research and Technology Organization, RTO) is focused on fostering simulation resource reusability within NATO and partners. Seven nations (Canada, Germany, France, The Netherlands, Spain, UK and USA) participate in this effort. MSG-042 is studying and analysing the factors that can enable a shared and common framework in which reuse of modelling and simulation resources will be supported. Our focus is not only on technical issues but also on organizational and cultural aspects that, as we have discovered, have a great impact on the capability of sharing resources, especially at multinational level.

MSG-042 recommendations will address three different aspects: reusability actors (Authorities, Producers, Consumers and Custodians), resources (any kind of item useful for simulation) and repositories (containers of resources). MSG-042 will also recommend a common architecture for connecting repositories and sharing resources.

This paper presents and discusses the findings of the MSG-042, including the conclusions drawn from the workshop that was held in The Hague (10th-12th May 05) on "Simulation reusability challenge within NATO".