... Click on an object in the solar system or choose from the list at left to learn more . The Arecibo Observatory planetary radar is the world's most powerful instrument for post-discovery characterization and orbital refinement of near-Earth objects. ... The Solar System Studies group is a department of the Arecibo Observatory, which is an NSF facility operated under cooperative agreement by SRI International, Universities Space Research Association (USRA), and la Universidad Metropolitana (UMET). ...