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Current NASA space suits use porous metal plate sublimators to reject the metabolic heat generated by the astronaut into space vacuum during EVA. Relying on tubular membranes instead of the flat plate of the sublimator, a proposed alternate unit has the potential to be smaller and lighter. This work outlines the operation of the proposed tubular membrane evaporator and the evaluation of possible membrane materials for the unit.

Fusible heat sinks are a possible source for thermal regulation of space suited astronauts. Historically, water has been the material of choice. Identification of alternative materials with greater thermal storage capability could enable both an extension of time between recharging, as well as a reduction in size. An extensive database search was undertaken to identify candidate materials with liquid solid transformations over the temperature range of -18°C (0°F) to 5°C (40°F); and 1215 candidates were identified. Based on available data, 59 candidate materials with thermal storage capability, ΔH values higher than that of water were identified. This paper presents the methodology utilized in the study, including the decision process used for materials selection. Future work will concentrate on measurement of thermodynamic data of the most promising materials so that the reliability of the data can be improved.

Astronaut cooling during extravehicular activity is a critical design issue in developing a portable life support system that meets the requirements of a space station mission. Some of the requirements are that the cooling device be easily regenerable and nonventing during operation. In response to this, a direct-interface, fusible heat sink prototype with freezable quick-disconnects has been developed. A proof-of-concept prototype has been constructed and tested that consists of an elastic container filled with normal tap water and having two quick-disconnects embedded in a wall. These quick-disconnects are designed so that they may be frozen with the ice and yet still be joined to the cooling system, allowing an immediate flow path. The inherent difficulties in a direct-interface heat sink have been overcome, i.e., (1) establishing an initial flow path, (2) avoiding low-flow freeze-up, and (3) achieving adequate heat-transfer rates at the end of the melting process.

An astronaut performing an extravehicular activity (EVA) exposes him/herself to many risks from which his colleagues inside the space vehicle are shielded. Among these are suit depressurization as a result of micrometeoroid impact and portable life support system (PLSS) failure. In addition, there is a risk of prolonged separation from the vehicle should a tether break or a manned maneuvering unit (MMU) run out of fuel. While it may be possible for the shuttle to retrieve and rescue a stranded crew member if necessary, the space station will not possess the required mobility to do so. In order to simplify contingency operations and to prepare for the situation when no other means is available, a self-rescue capability must be determined. A crew member working. on a remote area of the space station may become separated from his work site.