Dry Ice - Solid Carbon Dioxide

We have all seen the remarkable footage of astronauts performing extra-vehicular activity (EVA, or a "spacewalk"). The ability of an astronaut to survive outside his or her spacecraft depends on a highly engineered spacesuit that provides suitable life support functions and an appropriate environment. One of the challenges in suit design is maintaining an even temperature inside the suit. When the astronaut is in direct sunlight, the radiation from the sun heats the suit rapidly. When the astronaut moves into shadow, the temperature plunges precipitously. The suit must therefore have climate control functions including a cooling system.

Ingenious minds at NASA and Hamilton Standard developed a cooling system that depends on the process of sublimation. Sublimation is the direct conversion of solids into a gaseous form, typically by an evaporative process. The liquid phase is "skipped over" in this process. Sublimation is an endothermic process. In the "sublimator" system found in spacesuits, a block of frozen material (such as alcohol, glycol, water, etc) is separated from the vacuum of outer space by a thin porous metal plate. Molecules of the frozen material evaporate through the pores of the plate and escape to outer space. The plate is thereby cooled. Small capillaries carry water or other fluids across the surface of the cooled plate, which also functions as a heat exchanger. These circulating fluids become cooled, and they then flow throughout the suit to provide a cooled environment.

The porous plate is a crucial component of this process. The precisely defined and controlled pore distribution of a particular Dynapore® sintered wire mesh structure was found suitable for this demanding mission-critical application. MKI has been the sole source for this component for over thirty years, and has received citations from NASA for its role in the space program. Contact MKI today and see how we can custom design a laminate to suit your sublimation needs.