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A European Extra-Vehicular Activity (EVA) System is being developed by the European Space Agency (ESA) as part of its Hermes Programme, with the primary objective of providing a manned intervention capability for external servicing of the Columbus Free Flying Laboratory. The development phase started in 1988. A major design driver for the EVA system is the required level of failure tolerance, to ensure the achievement of sortie objectives and crew safety. The failure tolerance requirements placed on the EVA system may be summarised as follows: no single failure should result in sortie abort, and a safe return to the Hermes “safe-haven” should be possible following a second failure. This paper presents possible design solutions to this requirement, in particular for life support and associated functions. The failure tolerance characteristics of existing American and Russian EVA systems are also examined for comparison.

Gas-water separation is a fundamental requirement during long term operation of manned and man-tended space systems. Two areas of specific concern are in cabin humidity and temperature control and in gas removal from cooling water loops. This paper addresses design and testing of breadboard models for a condensate separator and a gas trap. Both models are based on semi-permeable membranes as main functional elements. The breadboard designs are driven by the requirements of the COLUMBUS space station. The condensate separator shall remove heat as well as water vapour from a humid air flow. Water shall permeate through the membranes, that are separating the air from the cooling water. The gas trap shall filter gas bubbles in a water loop and release the gas from the loop. In addition it shall maintain dissolved gas levels well below saturation.