Thermal finite element (FE) models, of low thermal conductance struts which are required to provide
support for the low temperature components of the Herschel Space Observatory, have been validated
by measurements at temperatures below 20 K. The Herschel Space Observatory structure is introduced.
FE modelling of two designs of support strut is briefly discussed and the final designs presented.
Validation of the design models was made in two experiments. The first of these provided specific
thermal conductivity data for component CFRP materials, whose composition was initially designed
on the basis of data available in the literature. The second experiment was performed to confirm the
thermal conductance (Q’/T), of the completed struts. The validation test rigs are described
together with details of the experimental methods employed. Values of conductance were at the level
of 5•10-5 W/K at a mean temperature of 6 K. The measured data are presented and discussed with
reference to the thermal models. Sources of measurement inaccuracy, are also discussed. |
