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Configurations similar to ’V-Grooves’, as already applied for radiators, can also insulate complete spacecraft and telescopes from solar radiation or hot modules several orders of magnitude better than the usual MLI. The specularity of surfaces contributes to the reduction of the radiation between the shields and thus improves the insulation. In this paper absorption factors between specularly and diffusely reflecting conical and rectangular areas are presented versus the ’V-angle’ in order to design such insulating configurations. Monte Carlo methods cannot be applied for very complex configurations if the number of surfaces is too large. The introduction of auxiliary areas with 100% specular reflectivity helps to simplify these geometries. Herein, the principle of this technique is first explained and proven by two examples of V-grooves. Then this method is applied for a specific configuration: three parallel plates which each have more than 8000 holes.

About 40 papers treating multilayer insulations were studied and compared. Most of these papers present heat transfer measurements in addition to thermal analysis. Here the equations are given which are required for an evaluation of the measurements and in particular for comparisons. Equations are presented which are required to predict the influences of the packing density, temperatures, fraction of perforation area and interstitial pressure. The equation giving gas conductivity versus pressure is modified according to measurements. In space the interstitial pressure is usually below 0.01 Pa und the heat transfer can be expressed as the sum of a conductive and a radiative term. The equation finally proposed for spacecraft permits to consider the influence of temperature, number of layers, blanket size and perforation area.