Design and Analysis of Launch Locks for JUICE Sub-Millimeter Wave Instrument

Abstract: Max Planck Institute for Solar System Research (MPS) in Göttingen, Germany planned to build a scientific payload Sub-Millimeter Wave Instrument (SWI) that will be on-board the Jupiter Icy Moon Explorer (JUICE) Spacecraft. The launch is expected in 2022. The main blocks of the instrument include Telescope and Receiver Unit (TRU), Radiator Unit (RU) and Electronics Unit (EU). The TRU consists of two main scanning mechanisms namely Cross-Track (CT) and Along-Track (AT) scanning mechanisms. This thesis describes the design of a conceptual Launch Lock (LL) that locks the scanning mechanisms. It also discusses the Quasi Static Load (QSL) and vibration simulations of Breadboard TRU. The main purpose of the LL is to lock the moving parts of a payload in a suitable position and release it after launch. Initial design of the LL was already developed at MPS but later due to design iterations it was completely changed considering mass and function. Topology Optimization Technique was implemented to check the Element Strain Energy Density Distribution in the parts which were later incorporated into the design. Two LL’s were developed with same operating principle one for CT and other for AT scanning mechanisms. Simulations were performed applying QSL on both LL’s and results were evaluated. Breadboard model of Burn Wire Release Mechanism (BWRM) and Tensioning Mechanism (TM) were designed to check the applicability of Dyneema and Vectran strings that keeps the LL in the locked position. The LL was designed successfully and integrated with the Breadboard TRU. The second main work discussed are the dynamic simulations of the Breadboard TRU. Launch loads that include sine and random loads are studied from the Experiment Interface Document Part-A (EID-A) drafted by European Space Agency (ESA). These loads were converted to a suitable form which could be directly used as an input for vibration simulations using Siemens NX Software with NX Nastran Solver.Normal Mode Analysis was performed to check the natural frequencies of the TRU. Acceleration and Von-mises stress plots are generated under sine and QSL/random loads respectively. The results are discussed further. From the simulation predicted results it is confirmed that TRU qualifies for a real time shaker test. Keywords: Cross-Track, Along-Track, Telescope and Receiver Unit, Quasi Static, Normal Mode, Von-mises Stress, Sine and Random load.