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This paper reports on the thermal testing of AGILE (Astro-rivelatore Gamma a Immagini LEggero) satellite flight model, conducted in June/July 2006 at IABG test facility. The paper describe the satellite mission, the logic for the selection of the test configuration, the test set-up and the test phases. The test results are presented and test-model (of the scientific instruments) correlation analysis between measured and calculated are discussed.

The satellite AGILE (Astro-rivelatore Gamma a Immagini LEggero, “Light Gamma Ray Imaging Detector”) is a promising instrument for near-earth space research of the Italian Space(ASI) during the years 2007-2009: its scientific instrumentation has optimal imaging capabilities in both the gamma-ray energy range (30 MeV - 30 GeV) and hard X-ray range (15 - 45 keV). It will study the phenomena occurring in the high energy spectrum, such as: Active Galactic Nuclei, Gamma Ray Bursts, Gamma-ray Galactic Diffuse Emission, and more. The satellite was designed and built in years 2004-2006; this paper describes the design of the thermal control system of the satellite, with a survey of the flight prediction. As an example of uncertainty reduction, MLI performance characterization by test was done in an early phase of the AIV phase (i.e. well before the system level test), to meet stringent payload requirements in terms of temperature gradients and temperature stability.

Improvements on the thermal analysis for system perturbed by micro-thermal fluctuations are presented: the method applies to any kind of (small) perturbation, in particular to the random ones. Opposite to time domain conventional transient analysis, this method answers the need for frequency domain thermal analysis dictated by the newest scientific missions, with tight temperature stability requirements (expressed in the frequency domain). The small temperature fluctuations allow for assuming any thermal systems a linear one; hence linear system theory holds, and powerful tools to calculate key parameters like frequency response can be successfully employed. MIMO (Multi-Input-Multi-Output) systems theory is applied, the inputs being perturbations to the thermal system (boundary temperatures oscillations and power sources ripple of any shape: pulse, step, periodic, random, …), while the outputs are the temperatures of the sensible parts.

The EC (Experiment Container) FASES (Fundamental and Applied Studies on Emulsion Stability) is an ESA scientific payload dedicated to the investigations of emulsion stability. FASES will fly in the FSL (Fluid Science Laboratory) rack in the ISS Columbus module. The challenging requirements are the minimum temperature (−50°C) to be reached and the cooling rate to be achieved (2°C/min) for three different types of samples with an accuracy of 0.1°C. The identified solutions are two active temperature control devices based on thermo-electric coolers (TEC): a Thermostatic Chamber (THC) that manages two type of samples (ITEM-S and ITEM-F) a mini-calorimeter (CAL) that handles the third one (EMPI). Considering the operative ranges, a multi-cascade TEC has been selected to fulfill the requirements. The performance of a multi-cascade TEC made up of separate single stages is also investigated.