Browsing by Author "Ross, Amy"
Now showing 1 - 9 of 9
- Results Per Page
- Sort Options
Item Advanced Extra-vehicular Activity Pressure Garment Requirements Development(45th International Conference on Environmental Systems, 2015-07-12) Ross, Amy; Aitchison, Lindsay; Rhodes, RichardThe NASA Johnson Space Center advanced pressure garment technology development team is addressing requirements development for exploration missions. Lessons learned from the Z-2 high fidelity prototype development have reiterated that clear low-level requirements and verification methods reduce risk to the government, improve efficiency in pressure garment design efforts, and enable the government to be a smart buyer. The expectation is to provide requirements at the specification level that are validated so that their impact on pressure garment design is understood. Additionally, the team will provide defined verification protocols for the requirements. However, in reviewing exploration space suit high level requirements there are several gaps in the team’s ability to define and verify related lower level requirements. This paper addresses the efforts in requirement areas such as mobility/fit/comfort and environmental protection (dust, radiation, plasma, secondary impacts) to determine the method by which the requirements can be defined and use of those methods for verification. Gaps exist at various stages. In some cases component level work is underway, but no system level effort has begun; in other cases no effort has been initiated to close the gap. Status of on-going efforts and potential approaches to open gaps are discussed.Item NASA Advanced Space Suit Pressure Garment System Status and Development Priorities 2019(49th International Conference on Environmental Systems, 2019-07-07) Ross, Amy; Rhodes, Richard; Mcfarland, ShaneThis paper discusses the current focus of NASA’s Advanced Space Suit Pressure Garment Technology Development team’s efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Unit (xEMU) project’s International Space Station Demonstration Suit (xEMU Demo) project continues to be the team’s primary customer and effort. In 2018 the team was engaged in addressing hardware design changes identified in the Z-2 pressure garment prototype Neutral Buoyancy Laboratory (NBL) test results. These changes will be discussed. Additionally components whose first iterations were produced in 2018 will be discussed. A full pressure garment prototype, termed Z-2.5, was assembled that is composed of updated and first prototype iteration hardware. Z-2.5 NBL testing, performed from October 2018 through April 2019 will inform final design iterations in preparation for the xEMU Demo preliminary design review planned to occur in the third quarter of government fiscal year 2019. A primary objective of the Z-2.5 NBL testing is to validate changes made to the hard upper torso geometry, which depart from the planetary walking suit upper torso geometry that has been used over the last 30 years. The team continues to work technology development, with GFY2018 work being used to supplement and feed the gaps left by the scope defined for the xEMU Demo. Specifically, a Phase IIx Small Business Innovative Research Grant to mature durable bearings that are compatible with a dust environment and a grant funded by the Science Technology Mission Directorate, Lightweight and Robust Space Suit (LARSS) project, to mature planetary impact requirements and hardware will be described. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team’s technology investment priorities and needs.Item NASA’s Advanced Extra-vehicular Activity Space Suit Pressure Garment 2018 Status and Development Plan(48th International Conference on Environmental Systems, 2018-07-08) Ross, Amy; Rhodes, Richard; McFarland, ShaneThis paper presents both near-term and long-term NASA Advanced Extravehicular Activity Pressure Garment development efforts. The near-term plan discusses the development of pressure garments components for the first design iteration of the International Space Station exploration space suit demonstration configuration, termed the xEMU Lite. The xEMU Lite effort is targeting a 2024/2025 flight demonstration timeframe. The FY18 tasks focuses on either the initiation or maturation of component design, depending on the state of development of the components, and the assembly of a suit configuration, termed Z-2.5, that will be used to evaluate changes to the upper torso geometry in a Neutral Buoyancy Laboratory (NBL) test series. The geometry changes, which are being driven by the need to reduce the front-to-back dimension of the advanced extravehicular mobility unit, diverge from a proven shape, such as that of the Mark III Space Suit Technology Demonstrator. The 2018 efforts culminate in the Z-2.5 NBL test. The lessons learned from the Z-2.5 NBL test will inform the xEMU Lite design as the effort moves toward 2020 design verification testing and a critical design review in 2021. The long-term development plan looks to surface exploration and operations. Technology and knowledge gaps exist between the xEMU Lite configuration; a lunar surface capability, xEMU; and Mars surface suit, mEMU. The development plan takes into account both the priority and the anticipated development duration. The long-term development plan will be updated as risks are mitigated and gaps are closed, but its overarching structure will remain intact.Item Shock Hazard Prevention through Self-Healing Insulative Coating on SSA Metallic Bearings(47th International Conference on Environmental Systems, 2017-07-16) Ou, Runqing; Eberts, Kenneth; Skandan, Ganesh; Sivaguru, Shobana; Gleeson, Daniel; Hewes, Linda; Ferl, Janet; Scarborough, Stephen; Ross, AmyThe space suit contains metallic bearings at the wrist, neck, and waist, which are exposed to the space environment but are also able to contact the skin of the astronaut inside the suit. Currently, several methods are employed that help protect against electrical hazards, which include keep out zones, de-energizing power lines, plasma mitigation systems (plasma contactor unit), anodizing exposed metallic parts, and adhesively applied Kapton® film to cover exposed metallic parts. The present paper describes the development of a more permanent insulation method that is also easy to maintain. Shock hazard prevention has been addressed by developing an insulative multi-layer polymer coating on metallic bearings. The coating is less than 25 microns thick. The relatively thin multi-layer polymer coating stack is comprised of an epoxy-based primer layer, with an overlay of a self-healing coating. Not only does the top layer heal itself when the surface is damaged, but it does so at room temperature without manual intervention and the healing process can be repeated multiple times. Under normal wear and tear usage conditions, any minor damage to the surface can be healed autonomously. Deeper damages that penetrate through the coating can be healed by a heat stimulus above 60C, which can be achieved during routine maintenance. To date, the applicability of the Self-Healing Coating (SHC) system on 17-4 PH stainless steel, titanium and anodized aluminum, has been demonstrated. Both flat and curved surfaces, resembling that of a wrist bearing, have been coated and tested for electrical insulation, as well as mechanical properties, such as impact damage at ambient and cryogenic temperatures. The self-healing response of the SHC system under use conditions, will be described.Item The “Space Activity Suit” – A Historical Perspective and A Primer On The Physiology of Mechanical Counter-Pressure(49th International Conference on Environmental Systems, 2019-07-07) Mcfarland, Shane; Ross, Amy; Sanders, RobertSince the 1950s, mechanical counter-pressure [MCP] has been investigated as a possible alternative design concept to traditional extra-vehicular activity [EVA] space suits. While traditional gas-pressurized EVA suits provide physiological protection against the ambient vacuum by means of pressurized oxygen to at least 3.1 psia (160 mmHg), MCP provides protection by direct application of pressure on the skin by a fabric. In reviewing the concept, MCP offers distinct potential advantages to traditional EVA suits: lower mass, reduced consumables, increased mobility, increased comfort, less complexity, and improved failure modes. In the mid 1960s to early 1970s, Dr. Paul Webb of Webb Associates developed and tested such a suit under funding from NASA Langley Research Center. This “Space Activity Suit” [SAS] was improved many times while testing in the laboratory and an altitude chamber to as low as 0.3 psia (15 mmHg). This testing, and the reports by Webb documenting it, are often presented as evidence of the feasibility of MCP. In addition, the SAS reports contain a wealth of information regarding the physiological requirements to make MCP work at the time, which is still accurate today. This paper serves to document the Space Activity Suit effort and analyze it in today’s context.Item Testing of the Z-2 Space Suit at the Neutral Buoyancy Laboratory(47th International Conference on Environmental Systems, 2017-07-16) Meginnis, Ian; Rhodes, Richard; Larson, Kristine; Ross, AmyThe Z-2 space suit is the product of the last fifty years of NASA’s space suit research and testing experience. The Z-2 suit was originally developed as an exploration space suit for use on a planetary surface, such as the moon or Mars. However, Z-2 could also be used in microgravity at the International Space Station (ISS) to supplement or replace the existing Extravehicular Mobility Unit (EMU). To evaluate the microgravity performance of Z-2 for compatibility at the ISS, the suit was tested in NASA’s Neutral Buoyancy Laboratory, which is the primary microgravity testing environment for space suits. Seven test subjects, including five astronauts, performed various tasks that are representative of the tasks performed at the ISS. Test subjects performed tasks in the Z-2 suit and the EMU so that relative comparisons could be drawn between the two suits. Two configurations of the Z-2 space suit were evaluated during this test series: the ELTA configuration and the ZLTA configuration. The ELTA configuration, which was the primary test configuration, is comprised of the Z-2 upper torso and the EMU lower torso. The ZLTA configuration is comprised of the Z-2 upper torso with the Z-2 lower torso, which contains additional mobility elements. This paper discusses the test methodology and preliminary test results from the Z-2 NBL test series.Item Z-2 Architecture Description and Requirements Verification Results(46th International Conference on Environmental Systems, 2016-07-10) Graziosi, David; Jones, Robert; Ferl, Jinny; Scarborough, Steve; Hewes, Linda; Ross, Amy; Rhodes, RichardThe Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA’s Z series of spacesuits. The Z-2 is another step in NASA’s technology development roadmap leading to human exploration of the Martian surface. The suit was designed for maximum mobility at 8.3 psid, reduced mass, and to have high fidelity life support interfaces. The Z-2 suit architecture is an evolution of previous EVA suits, namely the ISS EMU, Mark III, Rear Entry I-Suit and Z-1 spacesuits. The suit is a hybrid hard and soft multi-bearing, rear entry spacesuit. The hard upper torso (HUT) is an all-composite structure and includes a 2-bearing rolling convolute shoulder with Z-1 Style lower arms and an elliptical hemispherical helmet. The lower torso includes a telescopic waist sizing system, waist bearing, rolling convolute waist joint, hard brief, 2 bearing soft hip thigh, Z-1 style legs, and walking boots with ankle bearings. The Z-2 Requirements Verification Plan includes the verification of more than 200 individual requirements. The verification methods include test, analysis, inspection, demonstration or a combination of methods. Examples of unmanned requirements include suit leakage, proof pressure testing, mass, man-loads, sizing adjustment ranges, internal and external interfaces such as in-suit drink bag, purge valve, and donning stand. Examples of manned requirements include verification of anthropometric range, suit self-don/doff, secondary suit exit method, donning stand self-ingress/egress and manned mobility covering eight functional tasks. The eight functional tasks include kneeling with object pick-up, standing toe touch, cross-body reach, walking, reach to the SIP and helmet visor. This paper will provide an overview of the Z-2 design. Z-2 requirements verification testing was performed with NASA at the ILC Houston test facility. This paper will also discuss pre-delivery manned and unmanned test results as well as analysis performed in support of requirements verification.Item Z-2 Prototype Space Suit Development(44th International Conference on Environmental Systems, 2014-07-13) Ross, Amy; Rhodes, Richard; Graziosi, David; Jones, Bobby; Lee, Ryan; Haque, Bazle Z. (Gama); Gillespie, John W.NASA’s Z-2 prototype space suit is the highest fidelity pressure garment from both hardware and systems design perspectives since the Space Shuttle Extravehicular Mobility Unit (EMU) was developed in the late 1970’s. Upon completion the Z-2 will be tested in the 11 foot human-rated vacuum chamber and the Neutral Buoyancy Laboratory (NBL) at the NASA Johnson Space Center to assess the design and to determine applicability of the configuration to micro-, low- (asteroid), and planetary- (surface) gravity missions. This paper discusses the ‘firsts’ that the Z-2 represents. For example, the Z-2 sizes to the smallest suit scye bearing plane distance for at least the last 25 years and is being designed with the most intensive use of human models with the suit model.Item Z-2 Threaded Insert Design and Testing(46th International Conference on Environmental Systems, 2016-07-10) Jones, Robert; Graziosi, David; Ferl, Jinny; Sweeney, Mitch; Rhodes, Richard; Ross, Amy; Scarborough, StephenNASA’s Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement was to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. The design of the interface flanges of the composites allowed some of the inserts to be a “T” style insert that was installed through the entire thickness of the laminate. The flange portion of the insert provides a mechanical lock as a redundancy to the adhesive aiding in the pullout load that the insert can withstand. In some locations it was not possible to utilize at “T” style insert and a blind insert was used instead. These inserts rely completely on the bond strength of the adhesive to resist pullout. It was determined during the design of the suit that the inserts did not need to withstand loads induced from pressure cycling but instead tension induced from torquing the screws to bolt on hardware which creates a much higher stress on them. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes testing that was performed to determine a k value for helicoil inserts in the Z2 suit and how the insert design was modified to resist a higher pull out tension.