RAD is a commercial Eclipse-based integrated development environment (IDE), made by IBM's Rational Software division, for visually designing, constructing, testing, and deploying Web services, portals, and Java EE applications.
RSA is a modeling and development environment that uses the Unified Modeling Language (UML) for designing architecture for C++ and Java EE applications and web services. RSA is built on the Eclipse open-source software framework and includes capabilities focused on architectural code analysis, C++, and model-driven development (MDD) with the UML for creating applications and web services.
RSA includes all the capabilities of RAD and more!