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The Total Off-gassing test purpose is to determine the identity and quantity of trace gas contaminants offgassed in areas of spacecraft where the crew will breathe the atmosphere. Two different air sampling methods were adopted in parallel during the off-gassing tests on the Multi-Purpose Logistics Modules (MPLM) by Alenia Spazio. The first method, based on NASA (National Aeronautics and Space Administration) requirements, foresees storage of collected air samples into stainless steel pressure cylinders. The second method proposed by ESA (European Space Agency), uses trace contaminants adsorption on Carbopack™ filled ceramic tubes. Sample lines route the samples collected inside the MPLM cabin, to the respective external collection points. Successively, the stored samples are chemically analyzed by Gas Chromatography / Mass Spectrometry (GC/MS) techniques and the module offgassing rates are calculated.

Microorganism accumulation and growth onboard a spacecraft may impact adversely on crew efficiency and safety as well as system, subsystems and payload. The results of test campaigns performed at Alenia Spazio in Summer 1993 are reported here. From them, some simple and effective prevention methods to be applied during the manufacturing and integration phases of a pressurised spacecraft have been identified and are here discussed. Although data obtained from Earth experience may be considered useful, it is uncertain and unfit for space station operational lifespan. Therefore, it is necessary to build a model of the phenomenon, able to provide a series of quantitative data as a function of different parameters related to environmental characteristics, crew, and on-board activities.

At present, limited tools are available to model atmosphere control and supply systems simply, in order to allow quick design assessments based on analytical performances. In this context, the utilization of PC based ESACAP adapted as an Atmosphere Control and Supply (ACS) simulation tool is described. The analyses results shown in this paper refer to the activities of MPLM baseline re-definition carried out in accordance with the Space Station re-configuration. As a consequence, in several cases the described analyses reflect conservative assumptions and have been performed in a parametric way so as to take the uncertainties into account.

The Mini Pressurised Logistics Module (MPLM), a cooperative project between NASA and ASI that will be designed, developed, produced, integrated and delivered by Alenia, is a pressurised volume devoted to the resupply and return of Space Station (SS)containerized cargo requiringapressurised environment, via the National Space Transportation System (NSTS). As a servicer for the SS, the MPLM will have to accomplish several trips between Earth and SS in support of logistic needs. Since the active payloads launched with MPLM (freezers and refrigerators) require resources during the transportation phase inside the NSTS, the MPLM has the peculiar capacity to exchange power, data and fluids with the Orbiter before docking to SS. Once docked to SS, the MPLM will be required to provide its full performance, making use of the resources available from the SS Node; nevertheless, in this phase some of the MPLM functions are demanded from the SS.

A Human Factors Engineering (HFE) analysis has been involved in the design process of the Mini Pressurized Logistics Module (MPLM) for the International Space Station (ISS) since the beginning, as an integrated part of the design support activities. The support of HFE in the configuration process has been directed towards the optimization of the MPLM design through the analysis and evaluation of all the interfaces occurring in the module - nominal and non-nominal - between the crew, the system and the subsystem equipment. In order to identify and analyze all the crew interfaces occurring inside the module, a systematic approach, involving different disciplines, is necessary. The integration of three different tools such as computer simulation, task analysis and mock-up test activities has been employed as an organic unit, in order to establish a comprehensive collection of useful data.

Space hardware design, as well as that for hardware destined to work in 1-g environment, needs to be submitted to a complete design verification process before final utilisation in nominal conditions. As space hardware ground verification is difficult and expensive, a design verification philosophy has been developed in order to reach, as far as possible, the highest degree of space hardware reliability and usability and hence to increase crew productivity via a perfect integration of man and machines. This activity is mainly based on a complete hardware testing process (first on ground, then in microgravity simulated environment and, at the end, during a short duration space mission) and on a correct test procedure preparation in order to avoid inconveniences during test execution. Opportunity for an application of the design verification philosophy has been given by Columbus Precursor Flights and the related MIRIAM '95 programme.

The Columbus Attached Pressurised Module (APM) is intended to support a shirt-sleeve environment for crew activities. Top level requirements therefore define a cabin air temperature and humidity range (the so-called “Comfort Box”), extreme air velocities for ventilation in the centra aisle, maximum mean radiant temperature of the cabin walls. Air temperature selectability has to be ensured with adequate accuracy across the whole range. The APM environmental control system, in particular the Temperature and Humidity Control (THC) system, is designed and verified against these parameters. Cabin thermal conditions can be evaluated by the APM Integrated Overall Thermal Mathematical Model (IOTMM), representing the general thermal behaviour of the APM, including the THC system. Heat loads due to APM subsystem equipment and payloads, solar flux and the crew itself have been considered in the analyses.

Aim of the Closed Habitat Environmental Control Sensors (CHECS) project has been the setting up of a complete, lightweight sensing system for monitoring the ambient conditions of plant growth in space missions. A complete sensor system has been developed and tested, based on a deep knowledge of plant needs, and on the typical plant behaviour in stress conditions. The main characteristic of the system is its compatibility with Silicon technology. This means high integrability, reduced dimensions, low weight, redundancy, simplicity and high reliability. All the sensors composing the systems have been produced by means of well developed solid state technology, including the MicroSystem Technology (MST) and Porous Silicon Technology (PST). The latter has proved in the last year to have considerable advantages over other approaches.