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The Sentinel-1 Mission is part of the Global Monitoring for Environment and Security (GMES) initiative whose overall objective is to support Europe's goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. The Sentinel-1 satellite is commissioned by ESA with Thales Alenia Space Italy as prime contractor and Astrium Germany as subcontractor for the Sentinel-1 SAR instrument. Sentinel-1 is an imaging radar mission at C-band aimed at providing continuity of data for user services. In particular, Sentinel-1 is aimed at providing data to the sea ice zones and the arctic environment, to surveillance of marine environment (wind speed, oil spill and ship detection) to monitoring and mapping land surfaces, and mapping in support of humanitarian aid in crisis situations.

With the introduction of it's FlexBUS concept, Dornier Satellitensysteme GmbH has successfully entered the stage for small satellite development and manufacturing. Especially with its significant involvement in the engineering activities of the GFZ/DLR small satellite project CHAMP and the responsibility to lead the NASA/DLR GRACE project, a major step forward has been achieved in establishing Dornier as a major small satellite contractor. The CHAMP satellite (Challenging Mini-Satellite Payload for Geophysical Research and Application) of the GFZ (GeoForschungsZentrum Potsdam) is the first realized FlexBUS satellite. During its 5 year mission in a polar orbit, CHAMP will measure the magnetic field and the gravity field of the Earth as well as the state parameters of the atmosphere and the ionosphere. For this purpose CHAMP is equipped with various sensors such as a high resolution accelerometer, fluxgate and Overhauser magnetometers and a Digital Ion Drift Meter.

Electro emissive (Esther) devices are thin sheets, whose infrared emissivity can be varied reversibly by electrical charging. Bonded to external surfaces of spacecraft radiators, they allow active control of the heat radiated to space while consuming negligible electrical energy. Due to the very low mass and power consumption of that novel component for space craft thermal control, considerable cost savings in development and operation can be achieved. In the current phase of the development the performance of the Esther devices, achieved in the laboratory, is optimised (where necessary) and consolidated. The applied processes of the thin film technology and the internal structure and materials of the different layers have been optimised w.r.t. reproducibility and stable performance. The manufacturing and the functional test of the Esther devices has been standardised and a number of prototypes were produced (about 200).

The redesign of the international Space Station Freedom (SSF) and funding constraints in the ESA member states caused a redirection of the development effort for the Attached Pressurised Module (APM). For the ECLSS the most important changes are the reduction in length of the module in order to make it compatible with the ARIANE V capabilities and the more severe cost constraints. As a result new concepts for the cabin loop were investigated leading to a decrease in cabin loop power consumption, mass and volume and a reduced development effort due to a lower number of items. In the previous concept a module internal loop with a flow rate of 864m3/hr and an Intermodule Ventilation (IMV) flow rate for air revitalisation to the station with 240m3/hr were installed. The revised boundary conditions with a reduced overall massflow rate of 540m3/hr allows the combination of the cabin loop and the IMV with limited impact on the total power consumption.

Manned space laboratories like the US Space Station Freedom or the european COLUMBUS APM are equipped with so-called racks for subsystem and payload accommodation. An important resource is air for cooling the unit internal heat sources, the avionics air. Each unit inside the rack must be supplied with sufficient amount of air to cool down the unit to the allowable maximum temperature. In the course of the COLUMBUS ECLSS project, a thermohydraulic mathematical model (THMM) of a representative COLUMBUS rack was developed to analyse and optimise the distribution of avionics air inside this rack. A sensitivity and accuracy study was performed to determine the accuracy range of the calculated avionics air flow rate distribution to the units. These calculations were then compared to measurement results gained in a rack airflow distribution test, which was performed with an equipped COLUMBUS subsystem rack to show the pressure distribution inside the rack.

The pressurized modules use water and air coolant circuits to remove the dissipated heat from the sources and to transport it to the heat sink. The advantage of the water loops is to provide a high heat removal capability at low power consumption well suited for high specific heat loads i.e. assemblies with high dissipation and small volume. Air coolant circuits offer a higher flexibility to account for different shapes of the equipments and for changes in the configuration of the loop. Thus they are better suited for assemblies with lower dissipation and do not impose as much design restrictions on assemblies as water loops. But they have a higher specific power demand compared to water loops. In the Columbus pressurized modules avionics air loops and cabin air loops are installed. Both of them belong to the Environmental and Life Support Subsystem (ECLSS).

Potential fires in the COLUMBUS Attached Pressurized Module (APM) shall be extinguished by reducing the O2 concentration in the atmosphere below 15 %. For this purpose a CO2-distribution system is foreseen. It injects CO2 stored in a tank into the volume where fire is to be extinguished. Due to its dimensions the most critical of these volumes is the subfloor with the stand-off areas. To investigate the fire suppression process a detailed three dimensional computational fluid dynamic analysis (CFD-analysis) was performed. The transient CO2-distribution mechanisms, forced convection and diffusion, were analyzed to examine the feasibility of the foreseen system and to optimize it. In this paper the governing physical processes and their implementation in the mathematical model of the problem are described. The very complex inlet conditions - speed of sound, tiny nozzles - are examined in detail to investigate a proper method for implementation in the mathematical model.

In the course of establishing a thermal mathematical model of the pressurized volumes of the HERMES Spaceplane, it was found that the flow field in these volume strongly influences the overall thermal behaviour of the ACS (Atmosphere Control Section). The analysis of the flow field was carried out to get more detailed information about the heat transfer between the walls and the air inside the Spaceplane. Furthermore, the effects of gravity and mixing of return air from other volumes were studied. The analysis was carried out with the PHOENICS Software Package, specially developed for fluiddynamic simulations. The results gained by use of a two dimensional flow field indicate that gravity effects are neglectible due to the relatively high air velocities of the forced convection prevailing during all mission phases. Free convection does not contribute to the air movement. With a three dimensional flow field model the mixing effects were studied.