Browsing by Author "Chai, Patrick"
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Item A mission concept to study multigenerational mammalian reproduction(46th International Conference on Environmental Systems, 2016-07-10) Rodgers, Erica; Simon, Matt; Chai, Patrick; Lewis, Weston; Neilan, Jim; Stillwagen, Fred; Williams, PhillipA team at NASA Langley Research Center conducted a study during which a conceptual space mission was designed. In this study, rodents are used as human analogs to gather biological and systems data in a relevant environment applicable to future settlements on Mars. The mission concept uniquely addresses the combined effects of long-durations (one-year or greater), autonomous and robotic operations, and biological responses to partial gravity with an emphasis on reproduction. The objectives of this study were to 1) understand challenges associated with designing an artificial gravity habitat that supports the reproduction and maturation of a large animal colony, 2) identify mission architectures and operational concepts to transport and maintain such a facility, and 3) identify fundamental science considerations for mammalian reproduction studies to inform vehicle design. A model demonstration unit was developed to visualize and test certain design concepts that resulted from these considerations. Three versions of this demonstration unit were built over the course of the study, each taking into account lessons learned from the previous version. This paper presents the updated baseline mission and spacecraft design concepts to achieve these objectives, with a specific emphasis on updates since publication in previous works. Analyses of the integrated system trades among the elements which make up the conceptual vehicle are described to address overall feasibility and identify potential integrated design opportunities. The latest iteration of the habitat robotics design and a conceptual design example for autonomous care of crew and systems are also presented. Finally, the conclusion of this conceptual design study, necessary future analyses to enable such a facility, and comments upon other applications of a similar exploration-focused research facilities are addressed.Item Comparing Trash Disposal to Use as Radiation Shielding for a Mars Transit Vehicle(47th International Conference on Environmental Systems, 2017-07-16) Ewert, Michael; Broyan, James; Semones, Edward; Goodliff, Kandyce; Chai, Patrick; Singleterry, Robert; Abston, Lee; Clowdsley, Martha; Wittkopp, Charles; Vitullo, NicholasA round trip to Mars will require lots of supplies and will generate lots of trash. Mission studies and technology development are underway for this and other human space exploration missions, and what to do with the trash is more than a casual question. Supplies regularly come to the International Space Station in a variety of visiting vehicles, and trash leaves in the same way. Separate disposable logistics module(s) could also be used with a Mars transit vehicle, but there may be better options. The benefits of using logistics items such as food and other supplies have been recognized for solar radiation event shielding. To maintain this benefit throughout the mission, used logistics that become trash must also be used for shielding. This paper explores the competing benefits of trash disposal during the journey versus keeping the trash on board to maintain radiation shielding for the crew. Periodic disposal options include bulk jettison via an airlock and gas venting after a trash-to-gas process. If the trash is kept on board, it could simply be stored with considerations for control of odor and gas production. Alternatively, trash could be processed with heat melt compactor technology to create radiation shielding tiles from all eligible waste material. In addition to listing qualitative benefits for various options, such as reduced smell or littering, quantitative mission benefits are calculated. Disposal of trash prior to key points in the mission such as Mars orbit insertion and trans-Earth injection can save significant propellant. Alternatively, use of trash as radiation shielding could reduce the need to launch dedicated shielding materials and allow recovery of additional resources such as water. All options explored, except for storage of raw trash in the vehicle, also free up habitable volume.