Ground-based Searches for Near-Earth Objects

Despite recent advances in space-based telescope technology, ground-based searches for Near-Earth Objects (NEOs) continue to dominate the discovery statistics. While the discovery rate of NEOs is somewhat stochastic, these surveys discover, on average, roughly 5-10 new NEOs per day. By 2010, over 90% of the largest NEOs (those with diameter > 1 km) had been discovered, but that fraction drops precipitously with decreasing object size. Since 1998, NASA’s NEO Observations program, now under the auspices of the Planetary Defense Coordination Office, has funded and coordinated the efforts of the survey programs in order to meet the congressional mandate to discover 90% of the NEOs greater than 140 m in diameter. Current and former NEO surveys include the Catalina Sky Survey, LINEAR, Spacewatch, Pan-STARRS, ATLAS, LONEOS, NEAT, ZTF, and the Mt. Lemmon Survey. By employing facilities with a range of capabilities and geographic locations (to hedge against down time due to poor weather), the NEO detection community is best able to discover the maximum number of NEOs. We present here an overview of the different ground-based surveys, highlighting recent discoveries and the strengths of each facility.