Optimization of Thermal Control Systems Dring Sciamachy Commissioning Phase 2002-01-2545

Sciamachy is a Dutch/German Earth Observation Instrument on the European Envisat satellite launched on 1 march 2002. The goal of the instrument is to observe concentrations of trace gases in the atmosphere. Due to the character of the instrument special thermal control methods have been incorporated in the instrument design. Amongst these are active thermal control loops for the optical bench module and the detector modules. The optical bench module is provided with three feedback-controlled heater loops. The detector modules, which are cooled with a passive cooler to circa 140 K, are stabilized with three heaters that are controlled via telemetry. During the commissioning phase the active thermal control systems in the instrument will be characterized in order to optimize their use during the operational phase. The paper will focus on the in-orbit observations and adaptations of the active thermal control systems. For instance: Effect of set-point variations, cross coupling between thermal control loops, actual thermal conduction of heatpipe network.