A satellite assembly is a compiled library (DLL) that contains “localizable” resources specific to a given culture such as strings, bitmaps, etc.
You are likely to use satellite assemblies when creating a multilingual UI application. They are used to deploy applications in multiple cultures, with 1 satellite assembly per culture (default behavior)
Source: http://blogs.msdn.com/b/global_developer/archive/2011/07/22/introduction-to-satellite-assemblies.aspx
