LICIACube Mission: The Fastest Fly-By Ever Done by a CubeSat

As SmallSats are gathering an ever-increasing importance for all types of space missions, they are asked more often to operate in harshest environments and to complete the most complex tasks. One of these demanding technical challenges arises in the frame of the planetary defense. Space missions towards asteroids have garnered the due attention in recent years and, in this regard, NASA has developed the Double Asteroid Redirection Test (DART) mission, in which the Italy will lend its contribution. While DART acts as a kinetic impactor deflecting the orbit of the asteroid Dimorphos, the moon of the targeted binary system Didymos, the Light Italian CubeSat for Imaging of Asteroid (LICIACube) collects and gathers valuable images of the effect of the DART impact on the rocky body. LICIACube will allow to study the structure and evolution of the ejecta plume resulting from the impact, and to model both impacted and non-impacted sides of Dimorphos. LICIACube is an Italian Space Agency (ASI) project, whose design, integration and testing have been assigned to the aerospace company Argotec. The scientific team is enriched by University of Bologna team, supporting the orbit determination and the satellite navigation, Polytechnic of Milan, for mission analysis support and optimization and INAF (National Institute of Astrophysics), which provides support in the scientific operations of the satellite, instrument calibrations and data exploitation. This work focuses on the fly-by of LICIACube which will be accomplished using the imaging capabilities provided by theArgotecHAWK-6 platform and by the autonomous navigation system. In order to acquire high-resolution images, LICIACube approaches Dimorphos at a relative distance of 55km. The very close fly-by, the high relative velocity of ∼7 km/s with respect to the asteroid and the need to keep LICIACube camera pointed at Dimorphos make the mission very challenging. In addition, since the binary asteroid system is ∼10 million kilometers away from Earth, the fly-by has to be performed with no real time commanding. As a result, LICIACube shall be able to autonomously analyze all information from its sensors to track the asteroid. The evaluation and subsequent solutions to this problem are presented in this paper, as well as a unit-level description of the parts included in the autonomous navigation system. Finally, an overview of the verification of both unit-level and system-level strategies is outlined