Landing Juventas on Dimorphos

The Juventas 6U CubeSat is part of ESA's Hera mission, currently en route to the binary asteroid system Didymos. Hera will arrive at the end of 2026 and deploy Juventas in early 2027 to investigate the binary system. It will observe  Dimorphos in particular  in the aftermath of the kinetic impact delivered by NASA's Double Asteroid Redirection Test (DART) from Self-Stabilized Terminator Orbits (SSTOs) around the system, At the end of the mission, Juventas will leave the SSTO for a controlled descent and a ballistic landing on Dimorphos, followed by surface operations of nominal duration of two mutual orbital periods (~24 h). Following touchdown, the CubeSat is expected to undergo several bounces before reaching its final resting configuration.

We present the landing scenario and the planned operations during this complex and high-risk phase of the mission. The descent, touchdown, and surface phases will be monitored by a coordinated set of Juventas instruments including the laser altimeter, the navigation camera, and the Inertial Measurement Units (IMUs). The GRASS gravimeter will be operational as well. The landing event is expected to be observed by Hera and by the companion CubeSat Milani. We discuss the expected spacecraft–surface interactions during touchdown and bouncing and their implications for the operations and observations.