NISP instrument thermal design, justification file and FEM study

Abstract

This document describes the NISP thermal architecture and the justification of its design. The demonstration of the validity of such design in terms of meeting the baseline requirements relies on the results of the detailed thermal FEM analysis of the instrument. The thermal architecture is based on the Instrument PLM thermo-mechanical configuration and on the favourable conditions of the L2 thermal environment. For this reason the driving objective of the NIP thermal design is to maximize exploitation of passive cooling and instrument performances while minimizing design complexity. The analysis has been performed using a finite elements code (Abaqus). The NISP CAD model has been imported in the Abaqus environment and detailed with a fine mesh structure (around 105 nodes): both the conductive and radiative heat transfer in operational and non-operational conditions has been simulated in three main thermal cases, Hot, Nominal and Cold conditions. Results in terms of heat loads at the main internal and external interfaces are reported together with the temperature distribution of the instrument units. This document shall be used as a reference for the NISP thermal design and FEM simulation, as it contains a description of all assumptions and definitions for the model.