One component of the Maryland School Performance Assessment Program (MSPAP) is the state's performance-based assessments, criterion-referenced tests that require students to apply what they know and can do to solve problems and display other higher-order thinking skills. This document helps parents, teachers, students, and other citizens understand the tasks of the MSPAP. "Planetary Patterns," the eighth-grade science language usage task is presented. The "Student Response Book" is an actual operational test material that contains questions and other directions and gives space for students to enter their responses. In this task, students respond to hypothetical data sent back by a space probe about a new solar system and apply this information to written descriptions of the new system and planetary motion. The task manipulative, a set of orbit data logs, is attached, and the "Examiner's Manual" presents the directions teachers give students as they prepare for the task. Because of the complexity of the tasks, the State Department of Education distributes these selected task materials only in conjunction with a brief presentation by an educator. (SLD)