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As a consequence of the reduced funding by the ESA Member States contributing to the Columbus and Manned Transportation Programmes, the Columbus Project has undergone two major cost reduction exercises since 1993. An important cost reduction was achieved in mid '93 by downsizing the Attached Pressurized Module (APM) from 8 to 5 Double Racks equivalent length. To reduce the costs further, in 1994 the European space industry took the opportunity of exploiting specific features of the APM common with those of other projects, potential candidates being the Mini Pressurized Logistic Module (MPLM), developed by the Italian Space Agency (ASI) for NASA, or the European developed Russian Data Management System (DMS-R). In addition simplifications in System Function and in the Verification approach and maximum use of Off-the-Shelf and Commercial/Aviation/Military (CAM) hardware were investigated.

The Columbus fire suppression procedure is based on a centralized CO2 distribution system which injects the CO2 stored in a tank into the volume where the fire has to be extinguished. The fire is detected in each volume by means of the so-called REP (Rack Essential Package), which contains a fan and the smoke sensor. In order to assess the Fire Detection and Suppression design concept and to identify possible critical areas, Alenia Spazio - with the support of Flowsolve UK, and on behalf of EUROCOLUMBUS - has performed an analysis using a Computational Fluido-Dynamic (CFD) tool. The rack containing the water pump assembly and other electronic equipment has been chosen for the study. As far as the Fire Detection is concerned, the simulation intends to predict the flow field established in the rack by the ventilation system and the transport of smoke by this velocity field from a supposed point source.

The Attached Pressurised Module (APM) is the European element of the NASA Space Station Freedom (SSF). The environmental control of the APM is obtained through the combined effort of the Water Loops of the Thermal Control Subsystem (TCS) and the Cabin and Avionics Loops of the Environmental Control and Life Support Subsystem (ECLSS). Although the specific functions of ECLSS and TCS are separately verified at subsystem (S/S) level, their overall qualification is completed only after having carried out the functional and performance verification of the integrated Environmental Control System (ECS) inside the APM. To this purpose too, an APM Engineering Model (EM) development has been included in the programme. The Engineering Model is the element prototype, fully representative of the APM Flight Model (FM) but for the quality of the EEE components, as they are requested to be MIL-grade but not Hi-Rel.

The Thermal/Environmental Control System (T/ECS) of the Columbus Attached Pressurised Module (APM) requires extensive modelling to assess the overall system performance and interfaces compatibility, and to verify the design capability of the specific functions of the Thermal Control System (TCS) and Environmental Control and Life Support System (ECLSS). The thermal/environmental design of APM relies on TCS active (Water Loop) and passive thermal control functions, while ECLSS provides racks air cooling and cabin temperature and humidity control. The selected modelling approach uses an Integrated Overall Thermal Mathematical Model together with a set of additional TMM's for detailed tasks. The Overall TMM (up to 900 nodes, written in ESATAN to exploit its special modularity features) allows the element thermal balance verification and the provision of the sink and interface temperatures for the equipment thermal design.

Air cooling of the avionics units (Subsystem equipment and Payloads) of the Columbus Pressurised Modules (PM) is performed via avionics loops, providing heat collection from dedicated racks and rejecting the collected heat load by means of an avionics heat exchanger (AHX). An overview of possible rack architectures, air loop accommodations and control solutions which are candidates for the Columbus PMs is presented. The system requirements have been assessed as a starting point, in order to define the requested capabilities and the constraints that the design of the rack and the loop has to fulfil. In particular, the architectures of the European single and double rack and of the U.S. double rack in Space Station Freedom (SSF) have been compared and the relevant options of accommodation in the avionics loops and functional interfaces have been investigated.

Acritalia has performed a preliminary definition of the Internal Multiscreen Insulation (IMI) which forms part of the external Thermal Protection System (TPS) of the Hermes space plane. The purpose of the insulation is to protect the space plane ‘Cold structure' from the high heat loads experienced during the vehicle reentry. The IMI is a flexible insulation and its design concept makes use of reflective foils separated by low density felted fibre materials. It is normally located between the external (rigid) shingles and the fuselage, but will also be used to prevent excessive heating of those zones behind the vehicle's ‘Hot Structure' (nose cap and wing leading edges). The IMI blanket capability must be such that, while withstanding a limit temperature of 1300° C and an ultimate temperature of 1450° C, it will maintain the cold structure below 200° C. The design life is 15 years or 30 flights. The minimization of mass is also a major constraint.