Chapter 96 - Thermal validation of the design of the CFRP support members to be used in the spatial framework of the Herschel Space Observatory

Abstract

This chapter validates FE thermal models of the support members for the low temperature components of the Herschel Space Observatory by measurements at 1.8K. The Herschel Space Observatory structure is briefly introduced. The thermal modeling of two designs of support member is discussed and the final designs presented. The cooling of these instruments is to be achieved by placing the optical bench inside a large cryostat which contains a superfluid helium tank at 1.6 K and uses a circulation loop to deliver the superfluid helium to the bench. Conductance is calculated from the heater power divided by the temperature difference observed across the samples, in units of W/K. The design of the validation test rig is described together with details of the experimental method. Observed results are presented and discussed with reference to the thermal model. The model is found to be valid to within 1.5×10-5 W/K in the lateral struts and 3.29×10-5 W/K in the interface struts, at a mean temperature of 6K.