Browsing by Author "Vijayakumar, Rajagopal"
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Item Filter efficiency and leak testing of returned ISS bacterial filter elements (BFEs) after 2.5 years of continuous operation(46th International Conference on Environmental Systems, 2016-07-10) Green, Robert; Agui, Juan; Berger, Gordon; Vijayakumar, Rajagopal; Perry, JayThe air quality control equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provide the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) filters deployed at multiple locations in each U.S. Segment module; these filters are referred to as Bacterial Filter Elements, or BFEs. As more experience has been gained with ISS operations, the BFE service life, which was initially one year, has been extended to 2-5 years, dependent on the location in the U.S. Segment. In our previous work, we developed a test facility and test protocol for leak testing the ISS BFEs. For this work, we will present results of leak testing of a sample set of returned BFEs with a service life of 2.5 years, along with efficiency and pressure drop measurements. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS beyond 2020. These results can provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.Item Proposed protocols for defining requirements and sizing of media-based filters for spacecraft and planetary lander applications(51st International Conference on Environmental Systems, 7/10/2022) Green, Robert; Vijayakumar, Rajagopal; Agui, Juan; Berger, Gordon; Johnson, MatthewThe air quality control equipment aboard future deep space exploration vehicles provide the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation in low gravity, and can experience short durations of peak dust loading from planetary surfaces for Lunar or Mars landers. The filter industry has established methods to properly size filters for a given particulate load, but requirements for the space or planetary application introduce additional considerations. In this work, a methodology for evaluating and sizing particulate filters for a Lunar surface pressurized environment will be presented, including estimating the loading and particle size distributions of the loading based on mission requirements. In addition, a scaling analysis from single filter media sheet to full-scale filters for this application, based on recent testing, will also be presented. The results of this study may provide meaningful guidance in early design phase for air revitalization systems utilizing media-based particulate filters for deep space exploration missions.