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This Paper summarizes the main results of the firing operations performed by the Liquid Apogee Engine (LAE) of ITALSAT F1 spacecraft that has been launched Jan. 15,91. This evaluation represents the final check step of the thermal design activities on the LAE & Thermal Shield Assembly and of the firing control strategy definition presented on the Paper: “Thermal Design, testing and firing control strategy of the Liquid Apogee Engine & thermal Shield Assembly for the ITALSAT program” included in the SAE's 20th ICES conference (1990). The ITALSAT mission has been characterized by two LAE firing operations to place the spacecraft in the final geosynchronous orbit; each firing duration being about 37 minutes.

The INTEGRAL (International Gamma Ray Astrophysics Laboratory) program is an ESA observatory scientific satellite to be used for gamma ray astronomy, while ARTEMIS (Advanced Data Relay and Technology Mission) is an ESA program to be used for data relay and technology demonstration. ARTEMIS was launched on the 12th of July 2001 with an Ariane V launcher from CSG, after successful completion of the System Environmental test campaign at ESTEC including Solar Simulation Thermal Balance tests on PFM (1998). INTEGRAL has been successfully launched on the 17th of October 2002 with a Proton launcher from Baikonour Cosmodrome, after completion of the System Environmental test campaign at ESTEC including Solar Simulation Thermal Balance tests on STM (1998) and PFM (2002).

The Fluid Science Laboratory (FSL) is an advanced multi-user facility for conducting fluid physics research in microgravity conditions. It will be installed in the Columbus module of the International Space Station (ISS) scheduled for launch in 2004. FSL is being developed by a European industrial team, led by ALENIA SPAZIO of Italy, and managed by the European Space Agency (ESA). The FSL Thermal Environment Control (TEC) establishes a defined thermal environment during the complete experiment duration to keep the experiment and the supporting subsystems within their thermal requirements. The TEC is further subdivided into three sections. The Air Cooling Section is based on the Avionics Air Assembly (AAA) which generates air streams inside the Facility to collect, by forced convection, the waste heat from the electronics belonging to the various Subsystems. The Secondary Water Loop (SWL) cooling Section provides the cooled water to the Experiment Container.

The use of the truss of the International Space Station (ISS) for the accommodation of several experiments, in the frame of the “Early opportunity for ISS utilization”, will have a lot of advantages such as the possibility of human or robotics intervention, the recovery of the experiment at the end of its life, visual inspection of the items and cost reduction with respect to an installation on a dedicated satellite. However, from the user point of view, the ISS generates a great number of disturbances and severe environmental conditions for the experiments providing constraints and affecting the performances in different areas (thermal, mechanical, and avionics). The present paper will discuss the thermal aspects (disturbances, constraints and performances) concerning three different projects, developed by Alenia Spazio Turin plant, that will be mounted on the truss of the ISS: Hexapod, Coarse Pointing Device (CPD) and Sky Polarization Observatory (SPOrt).

The Columbus laboratory module for the International Space Station (ISS) uses active thermal control for cooling of avionics and payload in the pressurized compartment. The Active Thermal Control Subsystem (ATCS) is based on a water loop rejecting waste heat to the Medium Temperature Heat Exchanger and Low Temperature Heat Exchanger on Node 2, part of the US Segment of the ISS. Flow and temperature control in the ATCS is achieved by means of the Water Pump Assembly (WPA) and the 3-Way Modulating Valve (WTMO) units. For the flow control the WPA speed is commanded so that a fixed pressure drop is maintained over the plenum with the avionics and payload branches. Adjusting the WTMO internal flow split permit the two active units to perform the CHX and plenum inlet temperature control. The WPA includes a filter and an accumulator to control the pressure in the ATCS and to compensate for leakage and temperature-dependent volume variations.

ESA and NASA agencies agreed to run an interface compatibility test at the EADS facility between the Columbus flight module and a duplicate ground unit of a currently on-orbit US International Standard Payload Rack, the Human Research Facility (HRF) Flight Prototype Rack (FPR). The purpose of the test was to demonstrate the capability to run US payloads inside the European ISS module Columbus. One of the critical aspects to be verified to ensure suitable operations of the two systems was the combined performance of the hydraulic controls resident in the HRF and Columbus coolant loops. A hydraulic model of the HRF FPR was developed and combined with the Columbus Active Thermal Control System (ATCS) model. Several coupled thermal-hydraulic test cases were then performed, preceded by mathematical analysis, required to predict safe test conditions and to optimize the Columbus valve configurations.

The Visual Video Target Switching Unit (VVTSU) is the control unit dedicated to the Visual Video Target (VVT). The VVTSA, grouping VVTSU and VVT, is a “two-boxes assy”, externally located on ATV Front Cone, used to allow ATV monitoring by crewmembers inside the ISS Service Module, during the final approach up to 500 m from the docking port. Alenia Spazio is the responsible of VVTSA and in particular of the design, assembly and qualification of the VVSTU unit: an Engineering Model (for avionic tests), a Qualification Model and two Flight Units (+ 1 Spare) have been designed, assembled and verified in Torino and L’ Aquila Laboratories. The VVTSU is powered during the Rendezvous and it presents a high power dissipation, if compared with the reduced dimensions. The thermal control of this unit has been realized using passive means: a high conductive coupling with the fixation bracket, jointed with a radiator on the VVTSU top face.

Radarsat-2 is a commercial Synthetic Aperture Radar satellite for earth observation. [1] The general stowed configuration is shown in Figure 1. In nominal operation mode, once deployed, the large SAR polarimetric Antenna (i.e. able to transmit and receive both horizontal and vertical polarisations) is inclined of about -29.8° versus the nominal direction of geodetic local surface normal (Right Looking mode). When is necessary to take images of South Pole, nominally not visible from SAR, the S/C must be rotated to the +29.8° position (Left Looking mode). During the Radarsat-2 thermal testing the S/C (PFM) was subjected to a first thermal balance/thermal cycling test in vacuum with simulation of external heat fluxes by means of I/R lamps and additional test heaters. A very complex thermal test configuration was required in order to simulate the continually varying thermal environment imposed by the S/C nominal sun-synchronous orbit and attitude.

ALTAN (ALenia Thermal ANalyser) is a tool developed in Alenia Spazio, for the thermal simulation of satellites. Distinctive features of ALTAN are the description of the system in terms of thermal objects that can be considered as high level primitives, the accurate modelling of the energy sources (planets and sun) and of the optical properties, the integration in a single tool of the steps of radiative, conductive and thermal calculations and of the post-process of the results. An example of ALTAN application is given for Bepi-Colombo mission to Mercury, in particular the modelling of the highly variable planet temperature and the directional optical properties of the planet surface.