Browsing by Author "Maryatt, Brandon"
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Item Improvements to On-Orbit Sleeping Accommodations(49th International Conference on Environmental Systems, 2019-07-07) Maryatt, BrandonUnited States On-Orbit Segment (USOS) crew members aboard the International Space Station (ISS) are each furnished with a Crew Quarters that serves as their personal private space for the duration of their expedition. Within these quarters, crew members use sleeping bags to provide a comfortable environment that is conducive to sleeping in microgravity. Microgravity presents unique challenges to obtaining good sleep. Sleep position preferences which are influenced by gravity are disturbed when the feeling is absent while other environmental factors prevent the familiar feeling of lying in bed. NASA developed a new US Sleeping Bag for USOS crew members launching aboard United States Crewed Vehicles (USCVs), using this opportunity to improve upon the current sleeping bag design based on lessons learned from years of living and working in space. The US Sleeping Bag design was based on the current sleeping bag’s design with enhancements to key features based on feedback from crew members and sleep study experts at the Johnson Space Center and the Ames Research Center. Key areas of improvement include facilitating thermal comfort in the warm Crew Quarters environment, ease of maintenance when replacing the inner lining, allowing for maximum versatility for adjustment to crew preference, and adding features for additional functionality such as accommodations for a pillow. Two US Sleeping Bags have flown aboard the ISS to date, utilized by veteran crew members who have experience with the existing sleeping bags and have provided feedback and comparisons for assessment. Enabling good sleep is essential for crew member health and productivity, especially in longer duration expeditions. This paper will detail the challenges with sleeping in microgravity and the enhancements made in development of the US Sleeping Bag to provide a better on-orbit sleep environment.Item Lessons Learned for the International Space Station Potable Water Dispenser(48th International Conference on Environmental Systems, 2018-07-08) Maryatt, BrandonThe International Space Station (ISS) Potable Water Dispenser (PWD) currently provides potable water for United States On-orbit Segment crew consumption in food and drink packages. The first PWD unit commenced on-orbit operation in early 2009 and is certified for 10 years of operation. A second PWD unit began development 3 years after the certification of the first PWD unit to extend support of the ISS beyond 2018. A number of design changes were incorporated into the second PWD unit based upon the on-orbit experience with the first PWD unit over those 3 years. Operational changes were developed in response to on-orbit issues, including the certification of a shock kit to address unacceptable microbial growth prior to PWD activation. A major redesign of the primary crew interface was developed to increase the ease of use and robustness of the system. This redesign was incorporated into the base design of the second PWD unit and also retrofitted into the first PWD unit on-orbit. Other observations over the years of sustaining the PWD have generated knowledge that can help direct the development of future potable water dispensers, such as updates to key design assumptions regarding crew and payloads usage of the PWD system. This paper will detail the lessons learned from the PWD systems to inform development of future potable water dispensing hardware for other vehicles.Item Microbial Growth Control in the International Space Station Potable Water Dispenser(47th International Conference on Environmental Systems, 2017-07-16) Maryatt, Brandon; Smith, MelanieThe International Space Station (ISS) United States On-orbit Segment currently provides potable water for crew consumption via the Potable Water Dispenser (PWD). The PWD receives iodinated water from the Potable Water Bus, removes the iodine biocide and filters the water for particulates and bacteria, and then dispenses the potable water into an attached food or drink package for consumption. The user can choose to dispense water at either ambient temperature (65°F-123°F [18°C-51°C]) or hot temperature (150°F-200°F [66°C-93°C]). The first PWD unit commenced on-orbit operation in 2009 and has been continually operated since. The second PWD unit completed certification in September 2015 and is to be launched on need when the first PWD unit requires replacement. Until then, the second PWD unit is undergoing periodic maintenance to prevent microbial growth during storage. Each PWD unit poses unique challenges in reducing microbial counts to acceptable levels. The first PWD unit’s effluent is currently sampled on-orbit monthly for coliform bacteria and quarterly for total number of bacterial colony forming units to validate that the system is providing potable water within the limits defined by the NASA ISS Medical Operations Requirements Document. This PWD unit also utilizes operational constraints in the form of Flight Rules to manage off-nominal scenarios (such as prolonged stagnation) requiring the use of high biocide concentrations to “shock” the system to return the unit to its fully serviceable state. The second PWD unit is currently disinfected every 6 months using an iodinated water solution to maintain the bacterial counts within acceptable levels. The disinfection process and timeline has been chosen to reduce the likelihood of unacceptable levels of bacterial growth, minimize the potential for biofilm formation, decrease the potential for corrosion caused by repeated disinfections, and lessen the overall cycling of the PWD unit to preserve hardware life.Item Processing of Packing Foams Using Heat Melt Compaction(44th International Conference on Environmental Systems, 2014-07-13) Harris, Linden; Alba, Richard; Wignarajah, Kanapathipillai; Fisher, John; Monje, Oscar; Maryatt, Brandon; Broyan, James; Pace, GregoryFoam is used extensively as packing material for items sent to the International Space Station (ISS). Although lightweight, foam is bulky and can occupy a large fraction of the limited ISS volume. Four chemically distinct foams have been used on the ISS. In descending order of current usage, these are Plastazote > Zotek > Minicel > Pyrell. Processing foam with the Heat Melt Compactor (HMC), a solid waste treatment system, has been proposed to reduce the volume of foams stored on spacecraft. Prior to HMC testing, Thermogravimetric Analyses were conducted on the four foams as a precaution to ensure that the thermal decomposition temperatures were not within range of HMC operation (≤180°C). Pyrell was not tested with the HMC because it is known to release toxic compounds and comprises less than 1.5% of total foam usage on ISS resupply flights. Zotek, Minicel, Plastazote LD24FR (low density), and Plastazote LD45FR (high density) were processed with the HMC at 130, 150 and 170°C. Volume was reduced by 82.6% on average (n=19; std dev=4.88). Hydrocarbons and several other compounds emitted during foam processing were measured using a Total Hydrocarbon Analyzer and FTIR. Effects of process temperature and foam type on exhaust composition are discussed. Feeding of foams into the limited size opening of the HMC compaction chamber is likely to be a challenge, particularly in microgravity. Some suggestions are proposed to facilitate feeding foam into the HMC. Processing packing foam with the HMC has been shown to substantially reduce foam volume, and also has the potential benefit of producing radiation-shielding foam tiles.Item Recommendations for Next Generation Crew Quarters(48th International Conference on Environmental Systems, 2018-07-08) Maryatt, Brandon; van Wie, Michael; Clark, ToniFour Crew Quarters (CQs) are currently operating aboard the International Space Station (ISS) to support United States On-orbit Segment (USOS) crew members. These CQs serve as each crew member’s personal, private space for activities such as sleeping, working, holding private medical or family conferences, changing clothes, and personal downtime. The CQs have supported the ISS continuously since 2008. Since then, crew members have generated ample feedback based on their experience with the CQ. A new, modified crew quarters concept was investigated to augment the existing CQs and support the future increased USOS contingent. This new design is based on the CQ while incorporating crew member feedback as well as new commercial technology. Key areas of improvement are carbon dioxide mixing and washout, general illumination technology and layout, reduced acoustic emissions at higher ventilation flow to allow for improved thermal management, and more versatile sleeping accommodations. The new crew quarters design is also constrained by present-day launch vehicles, which are not capable of launching full integrated racks. These limitations may also extend to exploration missions in which a deep space transportation vehicle is outfitted over the course of several missions. Private spaces are essential to ensuring the productivity and alertness of the crew working extended periods in space. This paper will detail experience with the CQs and provide recommendations for modifications that will better facilitate crew health during long-duration missions.