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The Alpha Magnetic Spectrometer (AMS-02) is a particle physics detector designed to be installed on the International Space Station for at least 3 years, in order to measure charged cosmic rays, and to search for dark matter, missing matter and antimatter. The silicon Tracker is the centre of AMS. It measures particle trajectories through AMS-02 strong magnetic field with a micron accuracy. The heat dissipated by the whole experiment is rejected to deep space by means of four radiators [4–5]: the two Tracker radiators assure the heat dissipation for the above mentioned silicon Tracker, and the two Main radiators reject to space all the heat dissipated by the power, command and control units. The four radiators have been designed, analyzed by means of detailed thermal mathematical models and finally constructed and tested. This paper focuses on the thermal mathematical models tuning to best fit the provided test data.

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to measure charged cosmic rays spectra and high energy photons on board of the International Space Station (ISS). The large acceptance (0.5 m2sr), the long mission duration (3 years) and the state of the art particle identification techniques will allow AMS to provide the most sensitive search up to date for the existence of anti matter nuclei and for the origin of dark matter. AMS02 now is in its final integration phase at CERN. To verify the functional performance of the detectors and of the key subsystems of the Thermal Control System under vacuum condition and to validate the thermal mathematical model of AMS02 a system level thermo-vacuum test will be performed in the Large Space Simulator (LSS) of ESA at ESTEC (the Netherlands).

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.

This paper reports on the approach followed for the TCS verification of the payload AMS-02 (Alpha Magnetic Spectrometer), aiming at the qualification of the entire system, in steps, for the space environment. AMS-02 is a state-of-the-art experiment composed by a stack of seven different particle detectors, each of them having its own electronics and control equipments. It will be installed on the International Space Station Starboard segment S3 of the main Truss, and will be a 6500 kg payload, with a power consumption of 2000 W. The verification philosophy is driven by the need to qualify the flight hardware and by the necessary confirmation and correlation of the thermal mathematical models, based on experimental data. The hardware used on AMS-02 is derived from the state-of-the-art ground based detectors for high energy physics, hence not yet proven for operations in vacuum and in extreme thermal environment.

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.

This paper reports on an automated technique for reducing lumped-parameter thermal models. The method is applied in case of a simple geometry (a flat radiator panel), first in steady state conditions and then a comparison in time-variable environment is carried on, assessing how the reduction procedure affects the effective thermal mass of the radiator. More complicated shapes are studied, including concave corners and holes. The technique is implemented by a Matlab® code and it is applied to reduce the heat-pipes- embedded-radiator model of AMS-02, an ISS external payload. The detailed and reduced models behaviour is simulated by SINDA® and the results are compared: existing specification for test-model correlation, regression line and histograms are used for the verification. Furthermore radiator functioning extreme situations are simulated to see the method validity limits in steady state, introducing the concept of ‘working volume’.

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 thermal vacuum / thermal balance test design and execution are described in the paper for the qualification campaign of 37 electronic units flown with the payload of ISS (International Space Station), i.e., AMS-02 (Alpha Magnetic Spectrometer). The tests are run in 10 separate test campaigns, across a time frame of 3 years (2002–2005). The tests have been carried on at NSPO (National Space Program Office in Taiwan), maximizing the time usage of thermal vacuum facilities. During each experimental campaign several units are tested at the same time, sharing the vacuum chamber volume. Because independent heaters are applied to each unit, the electronic crates can be tested at temperature levels different from one another. The reliability of thermal analysis is enhanced at each thermal balance test, with the final aim to fully validate the thermal mathematical model deviating less than 3°C from actual measurements.

The paper presents the simulation and the performance evaluation for an innovative Temperature and Humidity Control in a manned orbiting module. Starting from the EcosimPro® modelling capabilities, a Space Station Module has been built and a standard Temperature and Humidity Control (THC) has been designed, based on a classical PID (Proportional, Integral, Derivative) controller, suitably developed. After that, a fuzzy logic controller has been dsigned and thanks to EcosimPro programmability a fuzzy logic controller block has been created. The controller have been sized and its performances suitably simulated. Performances of the innovative controller are checked against the standard control techniques.

This paper reports on the Thermal Control System (TCS) of the AMS-02 (Alpha Magnetic Spectrometer). AMS-02 will be installed on the International Space Station (ISS) Starboard segment of the Truss in 2005, where it will acquire data for at least three years. The AMS-02 payload has a mass of about 6700 kg, a power budget of 2kW and consists of 5 different instruments, with their associated electronic equipment. Analytical integration of the AMS-02 thermal mathematical model is described in the paper, together with the main thermal design features. Stringent temperature stability requirements have been satisfied, providing a stable thermal environment that allows for easier calibration of the detectors. The overall thermal design uses a combination of standard and innovative concepts to fit specific instruments needs.