Abstract
The Near-Earth Asteroid Characterization and Observation (NEACO) mission is a concept study proposing to explore the fast-rotating asteroid (469219) 2016 HO3, one of Earth's few quasi-satellites. In this study, a SmallSat spacecraft performs a scientific investigation that characterizes the asteroid at a sufficient degree to enable future, more in-depth missions. The 166 kg NEACO spacecraft uses a low-thrust, solar electric propulsion system to reach HO3 within 22 months from launch. Its instrument suite consists of two optical cameras, two spectrometers, an altimeter, and a low-velocity impactor. Upon arrival at HO3, NEACO uses pulsed plasma thrusters to hover at varying altitudes to enable lit surface mapping, shape modeling, and surface spectroscopy. The spacecraft will then perform several flybys to estimate the asteroid's mass. Finally, NEACO releases a low-velocity impactor during very low-altitude hovering to validate the existence of regolith and estimate the magnitude of surface cohesion. The science operations are completed within 8 months and the total mission is completed in less than 3 years. The NEACO mission concept integrates novel small-body analyses and proximity operation techniques with high-technology-readiness-level spacecraft components to achieve its science objectives within a reasonable mission timeline.