The descent and bouncing path of the Hayabusa2 lander MASCOTat asteroid (162173) Ryugu

Abstract

Images from the Optical Navigation Camera system (ONC) onboard the Hayabusa2 spacecraft show the MASCOT lander during its descentto the surface of asteroid (162173) Ryugu. We used results from a previous stereo-photogrammetric analysis that provided precise ONC imageorientation data (camera position and pointing), ONC orthoimages, and an ONC-based 3D surface model to combine them with the visibilities of MASCOT itself and its shadow on-ground within the ONC images. We integrated additional information from instruments onboard MASCOT(MASMag, MARA, MASCam) and derived MASCOT's release position and modeled its free-fall descent path and its velocity over 350 s fromits release at ~41 m altitude above ground until its first contact with the surface of Ryugu. After first contact, MASCOT bounced over the surfaceof Ryugu for 663 s and came to rest at its first settlement point after four intermediate surface contacts. We again used ONC images that showMASCOT and partly its shadow and reconstructed the bouncing path and the respective velocities of MASCOT. The achieved accuracy for theentire descent and bouncing path is ~0.1 m (1 sigma).