Development of the Landing Leg Structure for CALLISTO

Abstract

In the scope of the project CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss back Operations) DLR, JAXA and CNES jointly develop a demonstrator for a reusable, vertical take-off, vertical landing rocket first stage. CALLISTO aims to demonstrate relevant technologies for the reusability of such vehicles and their structures in order to gather flight data and knowledge for their development. In the context of this project, a variety of challenging thermal and mechanical loads and requirements occur in particular due to descent and landing phase. This paper focuses on the development of the deployable landing legs and presents the evolved structural and thermal design, major FE analysis results and performed test activities to achieve a lightweight and reusable space structure, enduring all present thermal and mechanical loads during its lifetime. Particular attention is hereby placed on dynamic phases such as the deployment of the landing legs and the touchdown that represent the dimensioning load cases for the structural parts made of titanium and CFRP. In order to sustain the combined demanding thermal environment, the landing legs are equipped with a cork TPS.