The European Polar Platform is a remote sensing satellite with the primary objective in the ENVISAT-1 Payload configuration to monitor and study the earth and its environment. The platform thermal design is passive, assisted by heaters. The ENVISAT-1 Payload consists of several instruments which are responsible for their own thermal control and are required to be thermally decoupled from the platform.ENVISAT-1 platform thermal analyses are performed at various levels: system module instrument unit/subassembly The paper describes a typical system thermal analysis campaign in terms of: geometrical and mathematical models used configurations (e.g. stowed, deployed appendages) and attitudes (e.g. nominal, safe mode) analysed analysis content and results Specific aspects of the system analyses are discussed e.g. complexity of system model which is an assembly of several models established by different companies. Major issues/problem areas and achievements related to the system analysis campaign supporting the ENVISAT-1 PDR are also presented. Finally the verification approach is outlined with particular emphasis on the thermal analysis aspects.