Abstract. Among the challenges of managing NASA’s information systems is the management (that is, creation, coordination, verification, validation, and enforcement) of many different role-based access control policies and mechanisms. This paper describes an actual data federation use case that demonstrates the inefficiencies created by this challenge and presents an approach to reducing these inefficiencies using OWL. The focus is on the representation of XACML policies in DL, but the approach generalizes to other policy languages.