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Technical Paper

Anthropometric and Blood Flow Characteristics Leading to EVA Hand Injury

2009-07-12
2009-01-2471
The aim of this study was to explore if fingernail delamination injury following EMU glove use may be caused by compression-induced blood flow occlusion in the finger. During compression tests, finger blood flow decreased more than 60%, however this occurred more rapidly for finger pad compression (4 N) than for fingertips (10 N). A pressure bulb compression test resulted in 50% and 45% decreased blood flow at 100 mmHg and 200 mmHg, respectively. These results indicate that the finger pad pressure required to articulate stiff gloves is more likely to contribute to injury than the fingertip pressure associated with tight fitting gloves.
Technical Paper

Thermal Analysis of Lightweight Liquid Cooling Garments Using Highly Conductive Materials

2005-07-11
2005-01-2972
This paper presents the analysis findings of a study reducing the overall mass of the lightweight liquid cooling garment (LCG). The LCG is a garment worn by crew to actively cool the body, for spacesuits and launch/entry suits. A mass reduction of 66% was desired for advanced missions. A thermal math model of the LCG was developed to predict its performance when various mass-reducing changes were implemented. Changes included varying the thermal conductivity and thickness of the garment or of the coolant tubes servicing the garment. A second model was developed to predict behavior of the suit when the cooling tubes were to be removed, and replaced with a highly-conducting (waterless) material. Findings are presented that show significant reductions in weight are theoretically possible by improving conductivity in the garment material.
Technical Paper

Zero-Venting, Regenerable, Lightweight Heat Rejection for EVA Suits

2005-07-11
2005-01-2974
Future space exploration missions will require a lightweight spacesuit that expends no consumables. This paper describes the design and performance of a prototype heat rejection system that weighs less than current systems and vents zero water. The system uses regenerable LiCl/water absorption cooling. Absorption cooling boosts the heat absorbed from the crew member to a high temperature for rejection to space from a compact, non-venting radiator. The system is regenerated by heating to 100°C for two hours. The system provides refrigeration at 17°C and rejects heat at temperatures greater than 50°C. The overall cooling capacity is over 100 W-hr/kg.
Technical Paper

Using a Sweating Manikin, Controlled by a Human Physiological Model, to Evaluate Liquid Cooling Garments

2005-07-11
2005-01-2971
An Advanced Automotive Manikin (ADAM), is used to evaluate liquid cooling garments (LCG) for advanced space suits for extravehicular applications and launch and entry suits. The manikin is controlled by a finite-element physiological model of the human thermoregulatory system. ADAM's thermal response to a baseline LCG was measured.The local effectiveness of the LCG was determined. These new thermal comfort tools permit detailed, repeatable measurements and evaluation of LCGs. Results can extend to other personal protective clothing including HAZMAT suits, nuclear/biological/ chemical protective suits, fire protection suits, etc.
Technical Paper

Self Contained Atmospheric Protective Ensemble (SCAPE) Suits Redesign and Implementation at Kennedy Space Center

2005-07-11
2005-01-2959
The Self Contained Atmospheric Protective Ensemble (SCAPE) suits, worn at the Kennedy Space Center (KSC) have been updated from the original 1970's design. The suits were renamed Propellant Handlers Ensemble (PHE) but are still commonly referred to as SCAPE. Several modifications to the suit were done over the last 20 years to improve the design for operational use. However, anthropometric changes in the user population over time have not been addressed. The following study addressed anthropometric concerns in the current SCAPE population. It was found that all suits had at least one area in which the recommended upper limit was exceeded by technicians. The most common areas to exceed the upper limit were: waist circumference, chest circumference and upper thigh circumference. Forearm circumference posed the least concern unless using long gauntlet glove which cause the twist lock ring to be located at the forearm rather than the wrist.
Technical Paper

A New Method for Breath Capture Inside a Space Suit Helmet

2007-07-09
2007-01-3248
This project investigates methods to capture an astronaut's exhaled carbon dioxide (CO2) before it becomes diluted with the high volumetric oxygen flow present within a space suit. Typical expired breath contains CO2 partial pressures (pCO2) in the range of 20-35 mm Hg (.0226-.046 atm). This research investigates methods to capture the concentrated CO2 gas stream prior to its dilution with the low pCO2 ventilation flow. Specifically this research is looking at potential designs for a collection cup for use inside the space suit helmet. The collection cup concept is not the same as a breathing mask typical of that worn by firefighters and pilots. It is well known that most members of the astronaut corps view a mask as a serious deficiency in any space suit helmet design. Instead, the collection cup is a non-contact device that will be designed using a detailed Computational Fluid Dynamic (CFD) analysis of the ventilation flow environment within the helmet.
Technical Paper

A Test Plan for Sensitivity of Hollow Fiber Spacesuit Water Membrane Evaporator Systems to Potable Water Constituents, Contaminants and Air Bubbles

2008-06-29
2008-01-2113
The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning to compare the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source.
Technical Paper

Comparison of Equivalent System Mass (ESM) of Yeast and Flat Bread Systems

2003-07-07
2003-01-2618
The Equivalent System Mass (ESM) metric developed by NASA describes and compares individual system impact on a closed system in terms of a single parameter, mass. The food system of a Mars mission may encompass a large percentage of total mission ESM, and decreasing this ESM would be beneficial. Yeast breads were made using three methods (hand & oven, bread machine, mixer with dough hook attachment & oven). Flat breads were made using four methods (hand & oven, hand & griddle, mixer with dough hook attachment & oven, mixer with dough hook attachment & griddle). Two formulations were used for each bread system (scratch ingredients, commercial mix). ESM was calculated for each of these scenarios. The objective of this study was to compare the ESM of yeast and flat bread production for a Martian surface outpost. Method (equipment) for both types of bread production was demonstrated to be the most significant influence of ESM when one equipment use was assumed.
Technical Paper

Early Results of an Integrated Water Recovery System Test

2001-07-09
2001-01-2210
The work presented in this paper summarizes the early results of an integrated advanced water recovery system test conducted by the Crew and Thermal Systems Division (CTSD) at NASA-Johnson Space Center (JSC). The system design and the results of the first two months of operation are presented. The overall objective of this test is to demonstrate the capability of an integrated advanced water recovery system to produce potable quality water for at least six months. Each subsystem is designed for operation in microgravity. The primary treatment system consists of a biological system for organic carbon and ammonia removal. Dissolved solids are removed by reverse osmosis and air evaporation systems. Finally, ion exchange technology in combination with photolysis or photocatalysis is used for polishing of the effluent water stream. The wastewater stream consists of urine and urine flush water, hygiene wastewater and a simulated humidity condensate.
Technical Paper

Assessing Biofidelity of the Test Device for Human Occupant Restraint (THOR) Against Historic Human Volunteer Data

2013-11-11
2013-22-0018
The National Aeronautics and Space Administration (NASA) is interested in characterizing the responses of THOR (test device for human occupant restraint) anthropometric test device (ATD) to representative loading acceleration pulse s. Test conditions were selected both for their applicability to anticipated NASA landing scenarios, and for comparison to human volunteer data previously collected by the United States Air Force (USAF). THOR impact testing was conducted in the fore-to-aft frontal (-x) and in the upward spinal (-z) directions with peak sled accelerations ranging from 8 to 12 G and rise times of 40, 70, and 100ms. Each test condition was paired with historical huma n data sets under similar test conditions that were also conducted on the Horizontal Impulse Accelerator (HIA). A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software.
Technical Paper

International Space Station Waste Collector Subsystem Risk Mitigation Experiment Design Improvements

2002-07-15
2002-01-2304
The International Space Station Waste Collector Subsystem Risk Mitigation Experiment (ISS WCS RME) was flown as the primary (Shuttle) WCS on Space Shuttle flight STS-104 (ISS-7A) in July 2001, to validate new design enhancements. In general, the WCS is utilized for collecting, storing, and compacting fecal & associated personal hygiene waste, in a zero gravity environment. In addition, the WCS collects and transfers urine to the Shuttle waste storage tank. All functions are executed while controlling odors and providing crew comfort. The ISS WCS previously flew on three Shuttle flights as the Extended Duration Orbiter (EDO) WCS, as it was originally designed to support extended duration Space Shuttle flights up to 30 days in length. Soon after its third flight, the Space Shuttle Program decided to no longer require 30 day extended mission duration capability and provided the EDO WCS to the ISS Program.
Technical Paper

Aerogel-Based Insulation for Advanced Space Suit

2002-07-15
2002-01-2316
Future spacesuits will require thermal insulation protection in low-earth orbit (LEO), in the near-earth neighborhood and in planetary environments. In order to satisfy all future exploration needs and lower production and maintenance costs, a common thermal insulation is desirable that will perform well in all these environments. A highly promising material is a fiber-reinforced aerogel composite insulation currently being developed at the Johnson Space Center. This paper presents an overview of aerogels and their manufacture, a summary of the development of a flexible fiber-based aerogel for NASA by Aspen Aerogels, Inc., and performance data of aerogels relative to flexible commercial insulation. Finally, future plans are presented of how an aerogel-based insulation may be integrated into a spacesuit for ground testing as well as for a flight configuration.
Technical Paper

Spacesuit Radiation Shield Design Methods

2006-07-17
2006-01-2110
Meeting radiation protection requirements during EVA is predominantly an operational issue with some potential considerations for temporary shelter. The issue of spacesuit shielding is mainly guided by the potential of accidental exposure when operational and temporary shelter considerations fail to maintain exposures within operational limits. In this case, very high exposure levels are possible which could result in observable health effects and even be life threatening. Under these assumptions, potential spacesuit radiation exposures have been studied using known historical solar particle events to gain insight on the usefulness of modification of spacesuit design in which the control of skin exposure is a critical design issue and reduction of blood forming organ exposure is desirable.
Technical Paper

Development of Pressure Swing Adsorption Technology for Spacesuit Carbon Dioxide and Humidity Removal

2006-07-17
2006-01-2203
Metabolically produced carbon dioxide (CO2) removal in spacesuit applications has traditionally been accomplished utilizing non-regenerative Lithium Hydroxide (LiOH) canisters. In recent years, regenerative Metal Oxide (MetOx) has been developed to replace the Extravehicular Mobility Unity (EMU) LiOH canister for extravehicular activity (EVA) missions in micro-gravity, however, MetOx may carry a significant weight burden for potential use in future Lunar or planetary EVA exploration missions. Additionally, both of these methods of CO2 removal have a finite capacity sized for the particular mission profile. Metabolically produced water vapor removal in spacesuits has historically been accomplished by a condensing heat exchanger within the ventilation process loop of the suit life support system.
Technical Paper

Development of a Contaminant Insensitive Sublimator

2006-07-17
2006-01-2217
Sublimators have been used for heat rejection for a variety of space applications including the Apollo Lunar Module and the Extravehicular Mobility Unit (EMU). Sublimators are excellent candidates for heat rejection devices on future vehicles like the Crew Exploration Vehicle (CEV), the Lunar Surface Access Module (LSAM), and future spacesuits. One of the drawbacks of previous designs was sensitivity to contamination in the feedwater. Undissolved contaminants can be removed with filters, but dissolved contaminants would be left in the pores of the porous plates in which the feedwater freezes and sublimates. These contaminants build up and clog the relatively small pores (~3–6 μm), thereby blocking the flow of the feedwater, reducing the available area for freezing and sublimation, and degrading the performance of the sublimator. For the X-38 program, a new sublimator design was developed by NASA-JSC that is less sensitive to contaminants.
Technical Paper

Flexible Fabrics with High Thermal Conductivity for Advanced Spacesuits

2006-07-17
2006-01-2236
This paper describes the effort and accomplishments for developing flexible fabrics with high thermal conductivity (FFHTC) for spacesuits to improve thermal performance, lower weight and reduce complexity. Commercial and additional space exploration applications that require substantial performance enhancements in removal and transport of heat away from equipment as well as from the human body can benefit from this technology. Improvements in thermal conductivity were achieved through the use of modified polymers containing thermally conductive additives. The objective of the FFHTC effort is to significantly improve the thermal conductivity of the liquid cooled ventilation garment by improving the thermal conductivity of the subcomponents (i.e., fabric and plastic tubes).
Technical Paper

Phase II Testing of Liquid Cooling Garments Using a Sweating Manikin, Controlled by a Human Physiological Model

2006-07-17
2006-01-2239
An ADvanced Automotive Manikin (ADAM) developed at the National Renewable Energy Laboratory (NREL) is used to evaluate NASA’s liquid cooling garments (LCGs) used in advanced spacesuits. The manikin has 120 separate heated/sweating zones and is controlled by a finite-element physiological model of the human thermo-regulatory system. Previous testing showed the thermal sensation and comfort followed expected trends as the LCG inlet fluid temperature was changed. The Phase II test data demonstrates the repeatability of ADAM by retesting the baseline LCG. Skin and core temperature predictions using ADAM in an LCG/arctic suit combination are compared to NASA physiological data to validate the manikin/model. An additional Orlan LCG configuration is assessed using the manikin and compared to the baseline LCG.
Technical Paper

Rapid Microbial Analysis during Simulated Surface EVA at Meteor Crater: Implications for Human Exploration of the Moon and Mars

2006-07-17
2006-01-2006
Procedures for rapid microbiological analysis were performed during simulated surface extra-vehicular activity (EVA) at Meteor Crater, Arizona. The fully suited operator swabbed rock (‘unknown’ sample), spacesuit glove (contamination control) and air (negative control). Each swab sample was analyzed for lipopolysaccharide (LPS) and β-1, 3-glucan within 10 minutes by the handheld LOCAD PTS instrument, scheduled for flight to ISS on space shuttle STS-116. This simulated a rapid and preliminary ‘life detection’ test (with contamination control) that a human could perform on Mars. Eight techniques were also evaluated for their ability to clean and remove LPS and β-1, 3-glucan from five surface materials of the EVA Mobility Unit (EMU). While chemical/mechanical techniques were effective at cleaning smooth surfaces (e.g. RTV silicon), they were less so with porous fabrics (e.g. TMG gauntlet).
Journal Article

Common Helmet Design for Launch, Entry, & Abort and EVA Activities – A Discussion on the Design and Selection Process of Helmets for Future Manned Flight

2008-06-29
2008-01-1991
Effective helmet performance is a critical component to achieving safe and efficient missions along the entire timeline; from launch and entry events to operations in a micro-gravity environment to exploration of a planetary surface, the helmet system is the capstone of the pressurized space suit assembly. Each phase of a mission requires uncompromising protection in the form of a robust pressure vessel and adequate protection from impact, both interior and exterior, all while remaining relatively comfortable and providing excellent visual interaction with the environment. Historically there have been large voids between these critical characteristics with the primary focus concerning the pressure vessel first and impact protection and crew comfort second. ILC Dover, NASA-JSC, Gentex Corporation, and Hamilton Sundstrand formed an Integrated Product Team (IPT) and conducted a NASA funded study to research and evaluate new concepts in helmet design.
Technical Paper

Pilot Investigation: Nominal Crew Induced Forces in Zero-G

1992-07-01
921155
Vibrational disturbance magnitude and frequency on space-flight missions is often a critical factor regarding mission success. Both materials processing experiments and astronomical investigations have specific microgravity environmental requirements. Recent efforts have been made to quantify the microgravity environment on the Space Shuttle Columbia by measuring gravity levels produced by specific mission events such as Orbiter engine burns, treadmill and ergometer activities, crew sleep periods, rotating chair operations, and body mass measurement operations. However, no measurements have been made of specific, nominal crewmember activities such as translating about the middeck, flight-deck, or in the Spacelab. This report presents pilot-study data of test subject forces induced by intravehicular activities such as push-offs and landings with both hands and feet. Five subjects participated in this investigation.
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