Browsing by Author "Anderson, Molly S."
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Item Exploring Life Support Architectures for Evolution of Deep Space Human Exploration(45th International Conference on Environmental Systems, 2015-07-12) Anderson, Molly S.; Stambaugh, Imelda C.Life support system architectures for long-duration space missions are often explored analytically in the human spaceflight community to find optimum solutions for mass, performance, and reliability. But in reality, many other constraints can guide the design when the life support system is examined within the context of an overall vehicle, as well as specific programmatic goals and needs. Between the end of the Constellation Program and the development of the “Evolvable Mars Campaign,” NASA explored a broad range of mission possibilities. Most of these missions will never be implemented, but the lessons learned during these concept development phases may color and guide future analytical studies and eventual life support system architectures. This paper discusses several iterations of design studies from the life support system perspective to examine which requirements and assumptions, programmatic needs, or interfaces drive design. When doing early concept studies, many assumptions have to be made about technology and operations. Data can be pulled from a variety of sources depending on the study needs, including parametric models, historical data, new technologies, and even predictive analysis. In the end, assumptions must be made in the face of uncertainty. Some of these may introduce more risk as to whether the solution for the conceptual design study will still work when designs mature and data become available.Item Improved Dynamic Modeling of the Cascade Distillation Subsystem and Analysis of Factors Affecting Its Performance(45th International Conference on Environmental Systems, 2015-07-12) Perry, Bruce A.; Anderson, Molly S.The Cascade Distillation Subsystem (CDS) is a rotary multistage distiller being developed to serve as the primary processor for wastewater recovery during long-duration space missions. The CDS could be integrated with a system similar to the International Space Station Water Processor Assembly to form a complete water recovery system for future missions. A preliminary chemical process simulation was previously developed using Aspen Custom Modeler® (ACM), but it could not simulate thermal startup and lacked detailed analysis of several key internal processes, including heat transfer between stages. This paper describes modifications to the ACM simulation of the CDS that improve its capabilities and the accuracy of its predictions. Notably, the modified version can be used to model thermal startup and predicts the total energy consumption of the CDS. The simulation has been validated for both sodium chloride solution and pretreated urine feeds and no longer requires retuning when operating parameters change. The simulation was also used to predict how internal processes and operating conditions of the CDS affect its performance. In particular, it is shown that the coefficient of performance of the thermoelectric heat pump used to provide heating and cooling for the CDS is the largest factor in determining CDS efficiency. Intrastage heat transfer affects CDS performance indirectly through effects on the coefficient of performance.Item National Aeronautics and Space Administration Environmental Control and Life Support Technology Development and Maturation for Exploration: 2014 to 2015 Overview(45th International Conference on Environmental Systems, 2015-07-12) Gatens, Robyn L.; Anderson, Molly S.; Broyan, James L.; Macatangay, Ariel V.; Shull, Sarah A.; Perry, Jay L.; Schneider, Walter F.; Toomarian, Nikzad B.Over the last year, NASA has continued to refine the understanding and prioritization of technology gaps that must be closed in order to achieve Evolvable Mars Campaign objectives. These efforts are reflected in updates to the technical area roadmaps released by NASA in 2015 and have guided technology development and maturation tasks that have been sponsored by various programs. This paper provides an overview of the refined Environmental Control and Life Support (ECLS) strategic planning, as well as a synopsis of key technology and maturation project tasks that occurred in 2014 and early 2015 to support the strategic needs. Plans for the remainder of 2015 and subsequent years are also described.Item Water Recovery from Brines to Further Close the Water Recovery Loop in Human Spaceflight(44th International Conference on Environmental Systems, 2014-07-13) Jackson, W. Andrew; Barta, Daniel J.; Anderson, Molly S.; Lange, Kevin E.; Hanford, Anthony J.; Shull, Sarah A.; Carter, D. LayneFurther closure of water recovery systems will be necessary for future long duration human exploration missions. NASA’s Space Technology Roadmap for Human Health, Life Support and Habitation Systems specified a milestone to advance water management technologies during the 2015 to 2019 timeframe to achieve 98% H2O recovery from a mixed wastewater stream containing condensate, urine, hygiene, laundry, and water derived from waste. This goal can only be achieved by either reducing the amount of brines produced by a water recovery system or by recovering water from wastewater brines. NASA convened a Technical Interchange Meeting (TIM) on the topic of Water Recovery from Brines (WRB) that was held on January14-15th, 2014 at Johnson Space Center. Objectives of the TIM were to review systems and architectures that are sources of brines and the composition of brines they produce, review the state of the art in NASA technology development and perspectives from other industries, capture the challenges and difficulties in developing brine processing hardware, identify key figures of merit and requirements to focus technology development and evaluate candidate technologies, and identify other critical issues including microgravity sensitivity, concepts of operation, and safety. This paper represents an initial summary of findings from the workshop.