ARECIBO OBSERVATORY (AO) CONTINUES TO BE A LEADER IN ASTEROID SCIENCE THANKS TO ITS PLANETARY RADAR CAPABILITIES. AO PLAYS A CONTINUING CRUCIAL ROLE IN THE CHARACTERIZATION OF NEAR-EARTH AND POTENTIALLYHAZARDOUS ASTEROIDS (NEAS AND PHAS) THANKS TO ITS ABILITY TO CHARACTERIZE THE SIZE SHAPE SURFACE TOPOGRAPHY REGOLITH PROPERTIES BINARITY SPIN STATE AND ORBITAL PROPERTIES OF A DIVERSE SET OF NEAS THAT PASS CLOSE TO EARTH. AO OBSERVATIONS PROVIDE INFORMATION ON THESE NEAS THAT IS EITHER IMPOSSIBLE OR EXTREMELY DIFFICULT TO OTHERWISE OBTAIN WITH OTHER OBSERVATIONAL METHODS. AO DETECTED 67 NEAS AND TWO NEAR-EARTH COMETS IN 2017 ALONE AND HAS DETECTED 13 NEAS SO FAR IN 2018 AT TIME OF WRITING (RIVERA-VALENTIN 2018). OVERALL AO HAS CHARACTERIZED HUNDREDS OF NEAS (BENNER ET AL. 2008 LEJOLY ET AL. 2017) AND HELPED GIVE US INSIGHT INTO THE NATURE OF THE POPULATION. THE UNIQUE SCIENCE THAT IS RETURNED BY THE RADAR EXPERIMENTS AT AO (AND AT THE MORE AGILE BUT MUCH LESS SENSITIVE FACILITY AT THE GOLDSTONE DEEP SPACE COMMUNICATIONS COMPLEX) NOT ONLY PROVIDES UNPARALLELED CONSTRAINTS ON SPECIFIC ASTEROIDS OF INTEREST TO NASA AND TO THE COMMUNITY BUT ALSO MOTIVATES AND FACILITATES WORK ON RELATED SCIENCE GOALS (TAYLOR ET AL. 2017A). ASTEROID RADAR RESULTS INFORM MODELS OF ASTEROID PHYSICAL EVOLUTION AND DYNAMICAL EVOLUTION AND NARROW THE ASTEROID HAZARD TO EARTH (SEE E.G. REVIEW BY BENNER ET AL. 2015). IN PARTICULAR AO HAS RECENTLY OBSERVED MANY SO-CALLED ASTEROIDS IN THE NHATS (NEAR-EARTH OBJECT HUMAN SPACE FLIGHT ACCESSIBLE TARGETS STUDY) PROGRAM WITH 18 SUCH OBJECTS OBSERVED IN 2017 ALONE. THUS THE RADAR WORK AT AO IS RELEVANT TO THE NEOO PROGRAM AND IS A VITAL COG IN MULTIPLE ASPECTS OF NASA S GOALS IN SOLAR SYSTEM ASTRONOMY MISSION PLANNING AND SPACE EXPLORATION.