Earth and space-based NEO survey simulations: prospects for achieving the Spaceguard Goal

We have used an improved model of the orbit and absolute magnitude distribution of Near Earth Objects (NEOs) to simulate the performance of asteroid surveys. Our results support general conclusions of previous studies using preliminary Near Earth Asteroid (NEA) orbit and magnitude distributions and suggest that meeting the Spaceguard Goal of 90 % completion for Near Earth Objects (NEOs) greater than 1 km diameter by 2008 is impossible given contemporary surveying capabilities. The NEO model was derived from NEO detections by the Spacewatch Project. For this paper we developed a simulator for the Catalina Sky Survey (CSS) for which we had a complete pointing history and NEO detection efficiency. The good match between the output of the simulator and the actual CSS performance gives confidence that both the NEO model and simulator are correct. Then, in order to determine if existing surveys can meet the Spaceguard Goal, we developed a simulator to mimic the LINEAR survey, for which detailed performance characteristics were unavailable. This simulator serendipitously provided an estimate for the currently undiscovered population of NEOs upon which we base all our estimates of time to 90 % completion. We also developed a set of idealized NEO surveys in order to constrain the best possible survey performance in contrast to more realistic systems. A 100 % efficient, all-sky, every night survey, subject only to the constraints of detection above a specified air mass and when the Sun is 18 ° below the horizon provides a benchmark from which to examine the effect of imposing more restrictions and the efficacy of some simple survey strategies. Such a survey must have a limiting V-magnitude of 20.1 0.2 to meet the Spaceguard Goal