NISP thermal reduced model

Abstract

This document describes the NISP reduced thermal model revision after the STM TV/TB test, following feedback from ESA and Industry, and correlation with the instrument detailed FEM. A dedicated reduced TMM for the STM thermo-mechanical configuration inside the ERIOS chamber was built. This model was correlated with the results of the test. Finally the modifications required for STM TMM tuning have been reflected, when applicable, to the last issue of the NISP reduced TMM. The model was then correlated with the thermal FEM, checking all conductances across internal interfaces and the radiative contribution from the instrument cavity through the MLI shroud. The model has been run in the main thermal cases: Minimum and Maximum interface conditions, both with the NISP instrument ON and OFF. An Operational Nominal Case, defined by intermediate expected temperatures of the boundaries, is run to provide an average reference between the two extreme Max and Min Cases. The results of each case are presented. The document shall be used as a reference for the TMM, as it contains a description of assumptions and definitions for the TMM.