This paper describes a framework for studying and evaluating learning environments which contextualize school science content within a larger real-world scientific endeavor, such as carrying on a space mission. A central feature of this framework is its incorporation of recent research on content-specific personal interest. This framework was developed and tested in a pilot evaluation of the Challenger Learning Center's M.A.R.S. (Mission Assignment: Relief and Supply) learning activity. This activity consists of a series of classroom activities which prepare students for a simulated Mars mission at a museum-based learning center. The evaluation involved over 300 students, and provided evidence of the positive impact of this particular program on students' interests, attitudes, knowledge, and activities relative to both science and space science. This evaluation also demonstrated the usefulness of the framework which has been developed for studying contemporary science learning environments. (Author)