The HST Astronomy workbench project makes use of and extends the Learning Components framework developed at Northwestern University. Learning Components are a library of well designed, reusable software components that can be added to existing and new web-based applications and media. It is designed to add interactive and collaborative features to on-line research and electronic library systems.

Our philosophy is to avoid building a monolithic system. Instead our aim is to build small, reusable tools that add features to other systems and applications. This is important because our work cannot easily reproduce the functionality or quality of existing commercial multimedia and research software. The Learning Components framework is not an educational site or server. Instead it is a modular toolkit for building educational sites that are targeted at particular domain areas. The project goals are to:

• Lower the effort and technical skill required to incorporate highly interactive features in online multimedia learning materials
• Facilitate incorporation of on-line database systems, simulations, and research tools into on-line instruction.