Browsing by Author "Gentry, Gregory"
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Item Beyond LEO: Life Support Requirements and Technology Development Strategy(44th International Conference on Environmental Systems, 2014-07-13) Guirgis, Peggy; West, William; Heldmann, Michael; Samplatsky, Darren; Gentry, Gregory; Duggan, MatthewThis paper reviews basic Life Support Systems requirements for a conceptual Earth- Moon Libration Point-2 (EML-2) orbiting facility and conceptual early stage Lunar and Mars bases, highlighting commonalities and unique challenges for each. Recommendations are made for both near-term and long-term key technology development investments in a progressive approach to technology development that supports needs of the above missions and aligns with the current fiscally constrained environment. This approach leverages available commercial-off-the-shelf (COTS) hardware and already developed space-flight hardware, while providing the rationale for a corresponding modestly elevated risk posture intended to bring down development costs, and to prioritize which technologies unavailable through COTS are in highest need of development. The recommendations provide guidance for Life Support Systems technology development planning activities.Item Design and Delivery of Filter for Removal of Siloxanes from ISS Atmosphere(46th International Conference on Environmental Systems, 2016-07-10) Carter, Donald; Kayatin, Matthew; Wilson, Mark; Perry, Jay; Rector, Tony; Agui, Juan; Gentry, Gregory; Bowman, Elizabeth; Greene, RobertDimethylsilanediol (DMSD) has been identified as a problematic organic on ISS. This contaminant was initially identified in the ISS condensate and in the Water Processor Assembly (WPA) product water in 2010 when the Total Organic Carbon Analyzer (TOCA) detected an increasing TOC trend in the water produced by the WPA. DMSD is not a crew health hazard at the levels observed in the product water, but it may degrade the performance of the Oxygen Generation System (OGS) which uses the WPA product water for electrolysis. In addition, it can prevent the effective operation of the WPA catalytic reactor, and necessitates early replacement of Multifiltration Beds in the WPA. An investigation into the source of DMSD has determined that polydimethylsiloxanes (PDMSs) are hydrolyzing in the Condensing Heat Exchanger (CHX) to form DMSD. PDMSs are prevalent on ISS from a variety of sources, including crew hygiene products, adhesives, caulks, lubricants, and various nonmetallics. These PDMSs are also known to contribute to degradation of the CHX hydrophilic coating, rendering it hydrophobic and therefore adversely affecting its ability to effectively transmit water to the condensate bus. Eventually this loss in performance results in water droplets in the air flow out of the Heat Exchanger, which can lead to microbial growth in the air ducts and can impact the performance of downstream systems. Design concepts have now been developed for removing PDMS in the air stream before it can reach the CHX coating, thus preventing degradation of the coating and decomposition of the PDMS to DMSD. This paper summarizes the current status of the effort to deliver filters to ISS for removing PDMSs from the atmosphere before they can adversely impact the performance of the CHX coating and the WPA.Item Exploring the Benefits of Evolving ISS ECLSS Hardware to 3-D Printed Hardware for Lunar/Mars Surface Habitats: Trace Contaminant Control Subassembly Case Study(51st International Conference on Environmental Systems, 7/10/2022) Gentry, GregoryAs humans return to the moon and venture on to Mars, subsystem hardware needs to be designed to be repairable, replaceable and duplicatable in-situ to the maximum extent possible. To ship all hardware and spares that would be needed for a lunar or Mars surface habitat, based on ISS designs, would debilitate any space program�s mass and volume numbers. Anticipating improvements in 3-D printing, surface habitat ECLSS hardware should be re-designed to utilize this new approach. Ultimately, every part that is possible to 3-D print (metal and plastic) should be made that way from the start and the files and printer capability included in the habitat to maximize the possibility of repairs, replacements or to make additional units as the facility grows. Similarly, a recycling capability for the broken/damaged/used parts (metal and plastic) should exist to avoid waste and minimize raw material resupply. As a case study for this effort, this paper will explore the potential benefits of evolving the ISS Trace Contaminant Control Subassembly to 3-D printed hardware. It will also propose incorporation of ISS lessons learned for sizing, maintenance and repair, and suggest changes to utilize surface gravity to reduce installed and spares hardware mass and volume.Item How Do Lessons Learned on the International Space Station (ISS) Help Plan Life Support for Mars?(46th International Conference on Environmental Systems, 2016-07-10) Jones, Harry; Hodgson, Edward; Kliss, Mark; Gentry, GregoryHow can our experience in developing and operating the International Space Station (ISS) guide the design, development, and operation of life support for the journey to Mars? The Mars deep space Environmental Control and Life Support System (ECLSS) must incorporate the knowledge and experience gained in developing ECLSS for low Earth orbit, but it must also meet the challenging new requirements of operation in deep space where there is no possibility of emergency resupply or quick crew return. The understanding gained by developing ISS flight hardware and successfully supporting a crew in orbit for many years is uniquely instructive. Different requirements for Mars life support suggest that different decisions may be made in design, testing, and operations planning, but the lessons learned developing the ECLSS for ISS provide valuable guidance.Item International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events 2016-2017(47th International Conference on Environmental Systems, 2017-07-16) Gentry, GregoryNov 2, 2016 marks the completion of the 16th year of continuous human presence in space on board the International Space Station (ISS). After 48 expedition crews, over 115 assembly & utilization flights, over 180 combined Shuttle/Station, US & Russian EVAs, the post-Assembly Complete ISS continues to fly and the engineering teams continue to learn from operating its systems, particularly the life support equipment. Major events and challenges for each U.S. ECLS subsystem occurring during the last year are summarily discussed in this paper, along with look ahead for the future of each U.S. ECLS subsystem.Item International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events: 2014 - 2015(46th International Conference on Environmental Systems, 2016-07-10) Gentry, GregoryNov 2, 2015 marked the completion of the 15th year of continuous human presence in space on board the International Space Station (ISS). After 42 expedition crews, over 115 assembly & utilization flights, over 180 combined Shuttle/Station, US & Russian EVAs, the post-Assembly Complete ISS continues to fly and the engineering teams continue to learn from operating its systems, particularly the life support equipment. Problems with initial launch, assembly and activation of ISS elements have given way to more long term system operating trends. New issues continue to emerge. Major events and challenges for each U.S. ECLS subsystem occurring during the last year are summarily discussed in this paper, along with look aheads for what might be coming in the future for each U.S. ECLS subsystem.Item International Space Station Environmental Control and Life Support System Mass and Crewtime Utilization In Comparison to a Long Duration Human Space Exploration Mission(45th International Conference on Environmental Systems, 2015-07-12) Bagdigian, Robert M.; Dake, Jason; Gentry, Gregory; Gault, MattOver the last two-and-a-half decades, the International Space Station’s (ISS) Environmental Control and Life Support System (ECLSS) has grown and evolved in size, complexity, and capability. The functions that it performs today are many of those that will need to be performed in the future aboard spacecraft and habitats that will enable long duration human exploration missions to destinations beyond low earth orbit. Regardless of the particular deep space destination, it is widely accepted that highly reliable ECLS systems that depend minimally on expendable equipment will be required. An important question, particularly in today’s fiscally- constrained environment, is how well suited is the ISS ECLSS suite of technologies to meeting the needs of future missions? To help begin answering this question, the maintenance history of the ISS Water Recovery and Oxygen Generation Systems has been surveyed. Equipment mass utilization rates, achieved hardware operating lifetimes, and crewtime spent on maintenance tasks have been tallied to provide a surrogate measure of reliability. These data are also compared to notional targets for a hypothetical three-year Mars mission.Item ISS as a Test Bed for Exploration ECLS Technology Development and Demonstration(47th International Conference on Environmental Systems, 2017-07-16) Gentry, Gregory; Duggan, Matt; West, William; Samplatsky, DarrenThis paper will discuss opportunities for advancing the Environmental Control and Life Support (ECLS) requirements and technologies needed for space exploration beyond low earth orbit, including some lessons learned, items already planned for use on the International Space Station (ISS), along with what should be/might be added. Also discussed will be possible crew training deltas (e.g. time delays) to demonstrate and experience anticipated operational differences (e.g. deep i-level repairs, crew managed local ppO2, ppCO2 and water management).Item Lunar Surface Habitats as a Development Opportunity for Mars Surface Life Support Systems(46th International Conference on Environmental Systems, 2016-07-10) Gentry, Gregory; Duggan, Matt; West, William; Samplatsky, DarrenThe development of Mars surface systems will require extensive development testing to make a first-time human mission to Mars successful and cost-effective. As our nearest surface destination, the Moon provides excellent surface systems analogs and learning opportunities to develop Mars mission equipment, systems, processes and procedures. Among other systems and technologies capable of being tested on the Moon, a lunar habitat is ideal to test many ECLSS technologies and development sensitive architectural features. This paper will outline the path Mars ECLSS surface systems development must take to successfully establish and utilize a lunar habitat test bed by identifying the major steps and capabilities required, when these capabilities must be implemented to meet an achievable timeline for a mission to Mars and what other development must happen in parallel. Any long-term-stay surface habitat ECLSS will have many commonalities but also many major differences with the International Space Station and the Apollo Program ECLSS. These commonalities and differences will be discussed. The benefits of this approach to achieving a successful Mars mission will be summarized.Item Proposed International Space Station Life Support Hardware Changes for a Lunar/Mars Surface Human Habitat � Common Cabin Air Assembly Case Study(50th International Conference on Environmental Systems, 7/12/2021) Gentry, GregoryThe International Space Station (ISS) was designed to be a microgravity space station in Earth orbit. As such, many design features of the ISS Environmental Controls and Life Support Systems (ECLSS) were included specifically to facilitate microgravity operation of the many fluid systems. These features were usually complicated, costly and/or inconvenient in ways that made operation, maintenance and/or in-situ repair more difficult than for Earth-based systems. As a reference point for future lunar/Mars surface habitat ECLSS system designers, changes to the ISS ECLSS can be envisioned to take advantage of lunar/Mars gravity environments while also reducing complexity, mass, volume and cost. This paper will review the ISS Temperature and Humidity Control (THC) system Common Cabin Air Assembly (CCAA) as a case study and provide the author�s proposed changes to facilitate more optimized gravity designs and system operation. Where appropriate, reliability and maintainability improvements based on ISS operational experience and possible 3D printing options will be included.Item Spacecraft Human Rating / Human Safe Requirements Impacts on Life Support Systems Design(48th International Conference on Environmental Systems, 2018-07-08) Gentry, Gregory; Duggan, Matt; Samplatsky, Darren; West, WilliamThis paper will discuss concepts of human safety for spacecraft design and operation and how those concepts might be applied for deep space exploration at the moon and beyond. After discussing the history of the human rating of spacecraft and introducing a new definition of human safe, this paper will examine deep space Environmental Control and Life Support Systems (ECLSS) in this context and discuss the changes from a traditional human rating that would be introduced by the human safe approach.