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Cassini is a NASA/ESA mission to investigate the Saturn system. The Cassini launch was on October 15, 1997, from Cape Caneveral in Florida/USA. On board is the Cosmic Dust Analyzer (CDA). The CDA- instrument is of great thermal interest, because a large instrument with low power density, large surfaces, fine structure elements and extremely variable external heat loads bring very complex thermal interaction conditions and inconsistent thermal demands. As well CDA has to tolerate a wide range of heliocentric distances between 0.61 and 10 Astronomical Unites (AU). In a former paper we presented some aspects of the complex TCS of CDA and the thermal calculations, tests and investigations till and after the launch. The purpose of this paper is to understand some differences between thermal design requirements, calculations, tests on Earth and the behaviour in real space.

The Thermal Control System (TCS) ensuring the Allowable Flight Temperature (AFT) at extremely different thermal loads, caused from mission conditions for Roland Comet Lander is considered. The Comet Lander is a compact lightweight modular designed instrument with instrument openings in comet nucleus direction. Important for the thermal situation of the Comet Lander are the solar influences of heliocentric distances between 5,5 to 0,9AU, the unknown rotation period, the rotation axis direction and the dust influence from the comet. Following this, the power supply and the Thermal Control System for all the possibilities is a large problem for the mission.