Asteroid Impact Hazard Warning From the NEO Surveyor Mission

NASA’s Near Earth Object Surveyor mission, scheduled for launch in September 2027, is designed to detect and characterize at least two thirds of the Potentially Hazardous Asteroids with diameters larger than 140 m in a nominal 5-year mission. We describe a model to estimate the survey performance using a faster approach than the time domain survey simulator described in Mainzer et al. (2023). This model is applied to explain how the completeness for 5- and 10-year surveys varies with orbit type and asteroid size, and to identify orbits with notably high or low likelihoods of detection. Size alone is an incomplete proxy for impact hazard so for each asteroid orbit we also calculate the associated hazard based on the impact velocity and the relative likelihood of impact. We then estimate how effective the mission will be at anticipating impacts as a function of impact energy, finding that a 5-year mission will identify 87% of potential impacts larger than 100 Megaton (Torino-9, “Regional Devastation”). For a 10-year mission this increases to 94%. We also show how the distribution of warning time varies with impact energy.