The NEO Surveyor Near Earth Asteroid Known Object Model

The known near-Earth object (NEO) population consists of over 32,000 objects, with a yearly discovery rate of over 3000 NEOs per year. An essential component of the next generation of NEO surveys is an understanding of the population of known objects, including an accounting of the discovery rate per year as a function of size. Using a near-Earth asteroid (NEA) reference model developed for NASA's NEO Surveyor (NEOS) mission and a model of the major current and historical ground-based surveys, an estimate of the current NEA survey completeness as a function of size and absolute magnitude has been determined (termed the Known Object Model; KOM). This allows for understanding of the intersection of the known catalog of NEAs and the objects expected to be observed by NEOS. The current NEA population is found to be $\sim38\%$ complete for objects larger than 140m, consistent with estimates by Harris & Chodas (2021). NEOS is expected to catalog more than two thirds of the NEAs larger than 140m, resulting in $\sim76\%$ of NEAs cataloged at the end of its 5 year nominal survey (Mainzer et al, 2023}, making significant progress towards the US Congressional mandate. The KOM estimates that $\sim77\%$ of the currently cataloged objects will be detected by NEOS, with those not detected contributing $\sim9\%$ to the final completeness at the end its 5 year mission. This model allows for placing the NEO Surveyor mission in the context of current surveys to more completely assess the progress toward the goal of cataloging the population of hazardous asteroids.Comment: 27 pages, 18 figures, 3 tables. Accepted for publication in Planetary Science Journal (PSJ

Validation of the Survey Simulator tool for the NEO Surveyor mission using NEOWISE data

The Near Earth Object Surveyor mission has a requirement to find two-thirds of the potentially hazardous asteroids larger than 140 meters in size. In order to determine the mission's expected progress toward this goal during design and testing, as well as the actual progress during the survey, a simulation tool has been developed to act as a consistent and quantifiable yardstick. We test that the survey simulation software is correctly predicting on-sky positions and thermal infrared fluxes by using it to reproduce the published measurements of asteroids from the NEOWISE mission. We then extended this work to find previously unreported detections of known near Earth asteroids in the NEOWISE data archive, a search that resulted in 21,661 recovery detections, including 1,166 objects that had no previously reported NEOWISE observations. These efforts demonstrate the reliability of the NEOS Survey Simulator tool, and the perennial value of searchable image and source catalog archives for extending our knowledge of the small bodies of the Solar System.Comment: 19 pages, 6 figures, accepted for publication in PS