Browsing by Author "MacKnight, Allen"
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Item Carbon Dioxide Removal Technologies for Space Vehicles - Past, Present, and Future(46th International Conference on Environmental Systems, 2016-07-10) Winton, Dale; Isobe, Jun; Henson, Phoebe; MacKnight, Allen; Yates, Stephen; Schuck, DarylAs NASA looks forward to human missions to long term deep space missions and the technologies required for them, it is essential to look back at the technologies that have been used to date in Low Earth Orbit and short term lunar missions in order to derive insights and lessons learned. This paper will provide a history of CO2 removal systems and components used throughout the history of U.S. human space missions, including Mercury, Gemini, Apollo, Shuttle, and international Space Station (ISS) programs. A parametric comparison of the systems utilized will be included, along with on orbit maintenance requirements, failure mechanisms, and contamination sensitivity. Advantages and disadvantages as well as lessoned learned are identified. Special emphasis is given to the Carbon Dioxide Removal Assembly (CDRA), which with over 15 years of operation on ISS continues to provide valuable insights and lessons learned that can and must be applied to future systems in order to ensure success of the missions they will support. With this history and lessons learned established, candidate technologies for CO2 removal on future deep space missions are introduced.Item Unit Operation Performance Testing of Cascade Distillation Subsystem(44th International Conference on Environmental Systems, 2014-07-13) Loeffelholz, David; Baginski, Ben; Patel, Vipul; MacKnight, Allen; Schull, Sarah; Sargusingh, Miriam; Callahan, MichaelThe Cascade Distillation System (CDS) is a waste water recovery technology being developed under NASA’s Advanced Exploration System (AES) water recovery project. The Cascade Distiller (CD) is the principal component of the CDS. The CDS prototype unit was extensively tested at NASA Johnson Space Center (JSC) during 2008 and 2009. In 2012 the need for additional CD testing was identified to determine thermodynamic, hydraulic, and distillation performance through experiment at operating conditions of interest. This paper discusses this operational testing performed at Honeywell in 2012 on the prototype Cascade Distiller. The thermodynamic performance demonstrated an average specific energy for recovered water of 92 watt-hr/kg. The limiting process recovery of distilled water was 95% of the feed on a weight basis. The distillation performance was tested using a chemical analysis method that used a water soluble red dye. This new method allows qualitative and quantitative measures of the concentrations of salt in the CD and the distillation efficiency.