Search Results

One of the key challenges facing NASA engineers is the development of systems for separating liquids and gases in microgravity environments. In this paper, a novel membrane-based phase separator is described. This device, known as a water recovery heat exchanger (WRHEX), overcomes the inherent deficiencies of current phase-separation technology. Specifically, the WRHEX cools and removes water vapor or water droplets from feed-air streams without the use of a vacuum or centrifugal force. As is shown in this paper, only a low-power air blower and a small stream of recirculated cool water is required for WRHEX operation. This paper presents the results of tests using this novel membrane device over a wide range of operating conditions. The data show that the WRHEX produces a dry air stream containing no entrained or liquid water--even when the feed air contains water droplets or mist. An analysis of the operation of the WRHEX is presented.

Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid- sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid- water stream.

Processes to remove and/or recover C02 from air are essential to the long-term success of the U.S. space program. In this paper, the results of a preliminary investigation of the use of a novel membrane-based system for removal of C02 from air are presented. Features of this technology that make it attractive include the following: 1) it is lightweight, 2) it requires no consumables or expendables, 3) it is relatively simple, and 4) it does not rely directly on other subsystems. Preliminary designs of systems for removing C02 from spacecraft cabin atmospheres and from the extravehicular mobility unit (EMU) are presented.