A trade-off study on the mechanical support structure of the MASCOT-2 small body lander package

The Mobile Asteroid surface SCOuT (MASCOT) is a 11 kg small body lander package developed under DLR lead for the Japanese space probe Hayabusa2. Based on MASCOT a modified MASCOT-2 lander package was studied for the AIM (Asteroid Impact Mission) mission study. The objective of the study was to develop a lander package, which maximizes heritage and reuse from the MASCOT predecessor. Thus the landing module’s framework structure retained the MASCOT design variant, being up-scaled by approx. 20% (MASCOT-2: 330mm x 300mm x 210mm, 13 kg). In contrast, the interface structure called Mechanical and Electrical Support Structure (MESS) experienced a more significant re-design, due to the need of interface simplification and the peculiarities of the lander deployment for AIM mission and the Didymos system. This paper introduces three possible design variants for the MESS, which are later narrowed down to two and presented in greater detail: a CFRP-honeycomb sandwich plate with additional unidirectional stiffening plies and an X-shaped solid CFRP hat beam structure. Both variants are much simplified compared to the MASCOT support structure, but retain the overall mounting variant. This conceptual discussion is followed by a detailed structural analysis of both mechanical support structures. Provided by a set of mechanical loads and stiffness requirements, the sandwich and beam interface structures are separately simulated in a finite element model, consisting of shell and beam elements, respectively. The attached landing module is modelled with both, shell and beam elements, allowing a coupled structural analysis of the system. By varying geometrical and material parameters in the structural MESS models, a trade-off between the resulting minimal masses, the stiffness and the strength requirements is performed. Specifically considering also development risks it is concluded that the sandwich design variant shows an overall better performance.