Thermo-elastic analysis in the frequency domain using the LISA instrument as a case study

Abstract

The thermo-mechanical stability requirements for the LISA instrument are some of the most demanding of any space mission. The associated analysis challenges to design the instrument and verify the requirements are well known, having been the subject of a number of ICES papers in the past � which have focused on both LISA and its precursor mission, LISA Pathfinder.

In past papers the focus was on techniques to address the thermal analysis in the frequency domain. This paper builds upon this previous work and presents an approach to carry out thermo-elastic analysis in the frequency domain. This approach has the potential to reduce the computational effort associated with this type of analysis, to lessen the impact of numerical errors, and to facilitate better understanding of the thermo-mechanical input-output behavior.

A case study, addressing the conceptual design and analysis of a support structure for the LISA instrument, is used to illustrate the presented method. Specifically an investigation into the performance of a thermally compensated structure, carried out at ESA/ESTEC, is presented.

The analysis tools used for the case study were ESATAN-TMS, pySINAS and NASTRAN for the thermal analysis, temperature mapping and mechanical analysis respectively. This analysis pipeline is described in the paper, however, the methods presented are technically applicable to any tool chain. As such, an outline of the theoretical background is presented, with emphasis placed on the thermo-elastic topic.