Observing Apophis’s 2029 Flyby from Earth–Moon L2 with LUMIO

(99942) Apophis will flyby the Earth on 2029 April 13 at an unprecedented close distance. This will be a unique opportunity to study a potentially hazardous asteroid (PHA) during a close encounter with our planet. This analysis assesses whether the Lunar Meteoroid Impact Observer (LUMIO), an ESA 12U Cubesat on a quasi-halo orbit around the Earth–Moon L2 point, can contribute to the observation of Apophis with any meaningful data. Radiometric models of the charge-coupled device (CCD) LUMIO-Cam and the environment are developed to analyze the capability of LUMIO to resolve the asteroid from the background. Sunlight reflections off the Earth and Moon are considered, as well as the noises of the detector and stray light. The geometry of the encounter is favorable for an observer placed on an orbit around the Moon, and LUMIO is indeed capable of detecting Apophis nearly a month before the flyby and of observing more than one spin rotation after it.