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This paper describes the Thermal Balance test that has been performed on EuTEF (European Technology Exposure Facility) platform, to be flown in October 2007 as an attached payload of Columbus module to the ISS. The thermal control system of EuTEF is based on a passive concept, with several different payloads being each one a self-standing technological experiment, with a centralized power supply and data handling. Each instrument has its own TCS, independent one another: they are individually insulated by MLI. The test has been performed with EuTEF Flight Model (FM) on the Passive Attach System to have representative thermal flight-like interfaces. Simulation of close-to-real flight environmental heat loads have been accomplished in a vacuum chamber (at INTESPACE, Toulouse-F) by means of a solar beam and a spin table suitably oriented to simulate a critical identified orbit, among all the possible on the ISS.

In the paper some methods are presented, with the corresponding practical examples, related to MonteCarlo (MC) techniques for thermal model/test correlation purposes. The MonteCarlo techniques applied to model correlation are intended to be used as an alternative to empirical ‘manual’ correlation techniques, gradients methods, matrix methods based on least square fit minimization. First of all, Design Of Experiments (DoE) tools are used to determine the model response to uncertain parameters and the confidence level of such a response. A sensitivity map is built, allowing the design of the test to maximize the response of the system to the uncertain parameters. Techniques derived from the extreme statistics are used to extrapolate data beyond test limits, with a sufficient confidence in the queue behaviour.

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.

The future Mars rover thermal design presents a unique challenge to the thermal engineers: the need arises for a thermal control system able to keep rover elements within their operational and non-operational temperature ranges in the face of extreme environmental conditions, characterized by broad day/night temperature excursions, cold biased conditions and long periods in standby modes induced by dust storms. A thermal device is needed, which allows the removal of excess heat from dissipating units during the Martian day and to keep them above their minimum operational/survival temperature during night. Moreover the scientific goals introduce strict requirements in terms of allowable internal components temperature ranges and thermal stability, which the candidate device has to fulfill against wide-ranging power dissipation modes. Such a device has been called Variable Thermal Conductance Device, or ‘Heat Switch’.

A Heat Switch has been developed, namely a device able to autonomously regulate its own thermal conductance in function of the equipment dissipation and environmental heat sink conditions. It is based on a Loop Heat Pipe (LHP) technology, with a passive bypass valve which diverts the flow to the Compensation Chamber when needed for regulation purposes. The target application is the potential use on a Mars Rover thermal control system. The paper recalls the Heat Switch design, and reports the results of an extensive test campaign on the ground demonstrator. The performance of the device was found extremely satisfying, and often exceeded the system requirements.

In the paper several application techniques of MonteCarlo (MC) method applied to thermal analysis of space vehicles are presented. Although these methods are widely used in other engineering domains, their introduction to the thermal one is quite recent and not fully developed in the industrial practice. This paper aims at showing that, even without demanding computation resources (all what presented has been obtained with a single processor PC) MonteCarlo analysis techniques, in a preliminary design phase, can support and integrate engineering judgment of the thermal designer. In particular, it is exploited the applicability of the method to reduced thermal models, with a clear advantage in terms of computation time. An original approach is proposed, and results are shown. The papers shows the applicability of the MC method to the case when experimental data of the uncertain parameters are available, using the bootstrap re-sampling techniques.

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.