A TRADE OF STUDY FOR THE STRUCTURE OF THE CALLISTO VEHICLE EQUIPMENT BAY

During the preliminary design of the Vehicle Equipment Bay (VEB), a section of the CALLISTO experimental launcher, three structural concepts emerged. This paper gives an insight into the trade of study, leading to a consolidated concept for detailed design. The different concepts of accommodation are described. From a mechanical standpoint, structural analyses for strength, stability and stiffness are presented. The VEB is loaded by aerodynamic forces acting on the fins (the aerodynamic control system FCS/A), longitudinal loads from the Nose Fairing, acceleration loads on equipment unit’s and ground load cases (handling for verticalization and lifting of the vehicle). Based on simplified assumptions, each concept is sized to obtain a feasible design. The resulting masses and amplifications are compared and used for the trade of study. Furthermore, the evaluation of the concepts from an Assembly, Integration and Test (AIT) point of view (demonstrate feasibility of mounting/dismounting of equipment’s, access to screw connectors and equipment screws, accessibility, harness length, growth potential), from a Maintenance and Refurbishment Operations (MRO) standpoint (access to batteries, specific access to some critical items) and from a safety point of view (position and segregation of the safety chains) is presented. The results are sorted and compared in a trade of table. The final design again is checked for feasibility and key performance values like mass and stiffness. An outlook is given on the impact of certain unit requirements like e.g. a horizontal integration.