Preliminary investigation of the Juventas CubeSat landing on asteroid Dimorphos

The Hera mission will launch in 2023/2024 and explore binary asteroid Didymos after the kinetic impact of the DART spacecraft. It carries two 6U CubeSats, one of which is the Juventas CubeSat developed by GomSpace Luxembourg with the Royal Observatory of Belgium as principal investigator. The spacecraft will attempt to characterize the internal structure of Didymos’s secondary body, Dimorphos, over a period of roughly 2 months using a low-frequency radar. Afterwards, it will attempt a ballistic landing on Dimorphos, during which the spacecraft is expected to perform several bounces. Juventas is equipped with high-rate accelerometers and gyros with which it aims to characterize the interactions with Dimorphos’s surface. Once landed, Juventas will also use its gravimeter to obtain in-situ measurements of the surface acceleration on Dimorphos along two of its orbits around the primary body.

In this research, we perform preliminary investigations of the bouncing of Juventas on Dimorphos. Unlike the previous dedicated asteroid lander spacecraft MINERVA-II and MASCOT, Juventas has two solar array wings, each consisting of three panels connected with torsional springs, that extend from its bus. These are expected to interact with the asteroid surface during the bouncing process. Using Lagrangian mechanics, we model the flexing and surface interaction of the spacecraft bus including these flexible solar arrays. This model is used to perform dynamical simulations of the Juventas bouncing, which allows us to estimate the settling time, settling distance, and settling attitude of the spacecraft, as a function of different surface properties and initial impact conditions.

By tracking the simulated accelerations experienced by the spacecraft, we also gain preliminary insight into the structure of the signals that will be measured by the accelerometers and gyros during landing. This will inform the next phases of system and mission design of Juventas and provides context to a dedicated test campaign in which we will experimentally characterize the impact behavior of the CubeSat.