Search Results

Three commercial off-the-shelf hollow fiber membrane evaporators, which were modified for low pressure, were tested as potential spacesuit water membrane evaporator (SWME) heat rejection technologies at pressures below 33 pascals in a vacuum chamber. Water quality was controlled in a series of 25 tests, first by simulating potable water that was reclaimed from wastewater and then by changing periodically to simulate the ever-concentrating make-up of the circulating coolant over that which is predicted over the course of 100 extravehicular activities. Two of the systems, which are comprised of nonporous tubes with hydrophilic molecular channels as the water vapor transport mechanism, were severely impacted by increasing concentrations of cations in the water. One of the systems, which was based on hydrophobic porous polypropylene tubes, was not affected by the degrading water quality or the presence of microbes. The polypropylene system, the SWME 1, was selected for further testing.

Performing extravehicular activity at various locations on the lunar surface presents thermal challenges that exceed those that have been experienced in space flight to date. The lunar Portable Life Support System (PLSS) cooling unit must maintain thermal conditions within the spacesuit (SS) and reject heat loads that are generated by both the crew member and the PLSS equipment. The amount of cooling that will be required varies based on lunar location and terrain due to the heat that is transferred between the suit and its surroundings, A study, which assumes three different thermal technology categories, has been completed that studied the resources that are required to provide cooling under various lunar conditions as follows: 1. SS water membrane evaporator 2. Sub-cooled phase change material (SPCM) 3.

A compact, low-power, electrochemically driven fluid cooling pump is currently being developed by Lynntech. With no electric motor and lightweight components, the pump is significantly lighter than conventional rotodynamic and displacement pumps. Reliability and robustness are achieved with the absence of rotating or moving components (apart from the bellows). By employing sulfonated polystyrene-based proton exchange membranes rather than conventional Nafion® membranes, a significant reduction in the actuator power consumption was demonstrated. Lynntech designers also demonstrated that these membranes possess the mechanical strength, durability, and temperature range that are necessary for long-life space operation. The preliminary design for a prototype pump compares very favorably to the design targets of the next generation spacesuit Portable Life Support Systems cooling pump.