Browsing by Author "Boyle, Robert"
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Item Metal Oxide Sorbent Deactivation Study(49th International Conference on Environmental Systems, 2019-07-07) Guerrero, Sandra; Auman, James; Boyle, Robert; Chase, Thomas; Goberman, Daniel; Macias, Brian; Nalette, TimothyThe metal oxide (METOX) CO2 scrubber technology was developed by UTAS in the early 1990s as a replacement for non-regenerable LiOH canisters used in NASA’s Extravehicular Mobility Unit (EMU) system or space suit. METOX has been the main CO2 scrubber since 1998, utilizing a silver oxide sorbent and alkali metal salts to capture metabolically produced CO2 in the form of silver carbonate which is thermally regenerated to silver oxide after each use. In 2015 a performance reduction in one of the Metox canisters was observed and while the system still met the established CO2 removal requirements, the causes leading to the performance reduction have not been clearly justified. However, one of the most likely reasons is suspected to be the deactivation or degradation of the sorbent material within the system. Therefore, United Technologies Aerospace Systems, (UTAS) in collaboration with United Technologies Research Center (UTRC), is conducting a study to investigate the potential sorbent degradation mechanisms. The preliminary testing will focus on the identification of potential contaminants in addition to any changes in crystalline structure, morphology and surface area of sorbent samples extracted from the “as returned from orbit” METOX canisters and comparing the results to a prepared baseline Metox sorbent sample. Additionally, the effect of thermal desorption at a temperature above the nominal regeneration temperature will be evaluated on these sorbent samples while collecting the desorbed gases for further trace contaminant analysis. Potential oxidation of gas phase contaminants and implication on reaction kinetics will also be addressed. Some of the analytical techniques used in the study will include: X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Electron Dispersive Spectroscopy (EDS), Thermal Desorption with Gas Chromatograph Mass Spectroscopy (GC/MS), and Brunauer-Emmett-Teller (BET) for surface area determination. This paper summarizes the preliminary test results, and discusses potential mechanisms of sorbent degradation.Item Spacesuit Water Membrane Evaporator Integration with the ISS Extravehicular Mobility Unit(44th International Conference on Environmental Systems, 2014-07-13) Margiott, Victoria; Boyle, RobertNASA has developed a Spacesuit Water Membrane Evaporation (SWME) to provide cooling for the next generation spacesuit. The current spacesuit team has looked at this technology from the standpoint of using the ISS EMU to demonstrate the SWME technology while EVA, and from the standpoint of augmenting EMU cooling in the case of a fouled EMU cooling system. One approach to increasing the TRL of the system is to incorporate this hardware with the existing EMU. Several integration issues were addressed to support a potential demonstration of the SWME with the existing EMU. Systems analysis was performed to assess the capability of the SWME to maintain crewmember cooling and comfort as a replacement for sublimation. The materials of the SWME were reviewed to address compatibility with the EMU. Conceptual system placement and integration with the EMU via an EVA umbilical system to ensure crew mobility and Airlock egress were performed. A concept of operation for EVA use was identified that is compatible with the existing system. This concept is extensible as a means to provide cooling for the existing EMU. The cooling system of one of the EMUs on orbit has degraded, with the root cause undetermined. Should there be a common cause resident on ISS, this integration could provide a means to recover cooling capability for EMUs on orbit.