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The Node 3 resource module plays a key role in the frame of the ISS in providing resources to the attached elements, berthing location to NSTS and crew habitable volume. The Internal Environmental Control System (IECS), TCS and ECLSS, has coolant loops and equipments flown at temperature below the maximum dew point (60 °F) allowed by requirements; as a consequence a proper insulation design is needed to avoid moisture condensate formation. Besides the respect of the basis requirement of preventing condensation, the insulation design shall meet several other requirements/design constraints like provide accessibility to items requiring inspection, robustness against incidental damages, good performances following exposure to vacuum conditions, axial continuity (absence of voids induced by displacement of adjacent mittens), easy reparability.

The Node 2 plays a key role in the frame of the ISS in providing resources to the attached elements (Columbus, JEM, CAM, MPLM), berthing location to NSTS and crew habitable volume. The Node 2 Environmental Control System (ECS) is therefore quite complex since it has to accomplish many functions in providing the required services. Purpose of this paper is to describe the Node 2 ECS as it has been designed, developed, qualified and built by Alenia Spazio and focus on particular issues encountered during the Node 2 design, indicating how they have been solved and outlining useful lesson learned.

A typical feature of an active loop thermal system is to guarantee a tight temperature range to the users through stable and fast control dynamics. In this framework, Alenia Spazio developed a dedicated Temperature Control Loop Analyzer (TeCLA) as a tool to assess the suitability of the software controlled algorithm for International Space Station (ISS) Nodes 2& 3 water loops. This tool defines the stability regions as a function of the control law gains and allows the screening of the operative scenarios to identify the worst cases, thus reducing costs by drastically limiting the candidates for a verification-development test campaign. This paper presents the TeCLA features and its application on the active thermal control loops of ISS Nodes 2& 3.

In the frame of a collaboration with ASI, NASA and ESA, Alenia Aerospazio is responsible for the design of several pressurized elements of the ISS: MPLM, COF, Cupola, Node 2 and Node 3. For Node 2 and Node 3 a “design synergy“ has therefore been pursued to exploit the gained experience as well as the day by day achieved know-how. Node 2 and Node 3 are pressurized elements of the ISS; they provide passageway among berthed habitable volumes, distribute electrical power and commands, collect and transport thermal energy by rejecting waste heat to ISS radiators. The Node 2 attached elements are the USL, the PMA2, the MPLM, the JEM, the COF, and the CAM. The Node 3 attached elements are the Node 1 (“Unity”), the CRV, the MPLM, the HAB and Cupola. Figure 1 shows the Nodes and the other Alenia developed elements integrated in the ISS.

The ISS resource Node 3 consists of a pressurized module, which provides passageway among habitable elements, distributes electrical energy and commands, collects and distributes thermal energy by rejecting waste heat to ISS radiators. This paper presents an overview of the Node 3 passive and active thermal control design and reports the most significant analysis results to evidence how the thermal and hydraulic requirements are satisfied. The Node 3 is being designed by Alenia Aerospazio following the know-how experienced on the Node 2, COF, MPLM and Cupolas Projects developed in the frame of a collaboration with ASI, NASA and ESA. Fig.1 shows a schematic representation of the ISS docked modules space configuration. The Node 3 TCS has two main sections, the PTCS and the ATCS.