The MAJIS (Moons And Jupiter Imaging Spectrometer) is an experiment designed for the Jupiter Icy Moons Explorer ESA mission (JUICE) whose objective is the study of the system of Jupiter and its moons Europa, Ganymede and Callisto. The mechanical design of the optical bench of the MAJIS is critical because of high experienced loading during launch. A sine excitation of 240 m/s2 amplitude in the frequency range from 20 to 80 Hz is present and beside that, a random excitation between 20 and 2000 Hz with an overall RMS of 45 m/s2 has to be overcome. In that view, a safe condition is to achieve a first natural frequency higher than 120 Hz. A preliminary design of the optical bench (OB) of the instrument has been achieved by MAJIS team but, in order to validate the developed FEM models and the performed mechanical and thermal analyses, a mockup of the OB has to be developed. Thus, a simplified model was designed to be tested within the expected thermal and mechanical environments. The simplified model was developed to achieve the same overall instrument mass and the same size derived by the thermal design. The mockup design has been guided by means of FE mechanical analyses, i.e. modal and quasi-static analyses. Finally, a mockup of the insulation and holding system of the MAJIS IR detector has been designed. Finally, a mockup of the insulation and holding system of the MAJIS IR detector has been designed, manufactured and assembled to be tested in the expected mechanical environment.
Il MAJIS (Moons And Jupiter Imaging Spectrometer) è uno spettrometro ad immagini progettato per la missione ESA Jupiter Icy Moon Explorer (JUICE) il cui obiettivo è lo studio del sistema di Giove e le sue lune Europa, Ganimede e Callisto. La progettazione meccanica del banco ottico del MAJIS è critica, a causa degli elevati livelli di vibrazione di tipo sweep sine e random attesi durante il lancio. Pertanto come requistito dinamico, si richede di raggiungere una prima frequenza propria superiore a 120 Hz. La progettazione del banco ottico (OB) dello strumento è stato conclusa e la relativa fattibilità dimostrata ma per procedere con i test meccanici e termici richiesti per la validazione dei risultati ottenuti, si deve sviluppare e realizzare un elemento dimostrativo del banco ottico. L’obiettivo di questo lavoro di tesi è lo sviluppo di tale modello. Il modello è stato sviluppato per ottenere la stessa massa complessiva dello strumento e mantenerne gli ingombri. La progettazione dell’elemento dimostrativo è stata effettuata sviluppando modelli ad elementi finiti dello stesso e utilizzando analisi modali e di verifica di resistenza ai carichi di progetto. Infine, un elemento dimostrativo del sistema di supporto ed isolamento del detector IR dello strumento MAJIS è stato sviluppato sempre attraverso l’utilizzo del metodo agli elementi finiti.Tale elemento dimostrativo è stato infine caratterizzato attraverso test meccanici rappresentativi dei livelli di vibrazione attesi durante le fasi di lancio.
Design of the MAJIS optical head mockup
PANAHI, REZA
2015/2016
Abstract
The MAJIS (Moons And Jupiter Imaging Spectrometer) is an experiment designed for the Jupiter Icy Moons Explorer ESA mission (JUICE) whose objective is the study of the system of Jupiter and its moons Europa, Ganymede and Callisto. The mechanical design of the optical bench of the MAJIS is critical because of high experienced loading during launch. A sine excitation of 240 m/s2 amplitude in the frequency range from 20 to 80 Hz is present and beside that, a random excitation between 20 and 2000 Hz with an overall RMS of 45 m/s2 has to be overcome. In that view, a safe condition is to achieve a first natural frequency higher than 120 Hz. A preliminary design of the optical bench (OB) of the instrument has been achieved by MAJIS team but, in order to validate the developed FEM models and the performed mechanical and thermal analyses, a mockup of the OB has to be developed. Thus, a simplified model was designed to be tested within the expected thermal and mechanical environments. The simplified model was developed to achieve the same overall instrument mass and the same size derived by the thermal design. The mockup design has been guided by means of FE mechanical analyses, i.e. modal and quasi-static analyses. Finally, a mockup of the insulation and holding system of the MAJIS IR detector has been designed. Finally, a mockup of the insulation and holding system of the MAJIS IR detector has been designed, manufactured and assembled to be tested in the expected mechanical environment.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/119844