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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

Wissler Simulations of a Liquid Cooled and Ventilation Garment (LCVG) for Extravehicular Activity (EVA)

2006-07-17
2006-01-2238
In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series of tubes through which cooling water is circulated. To better predict the effectiveness of the LCVG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Thermal Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained.
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

Thermal Performance of Space Suit Elements with Aerogel Insulation for Moon and Mars Exploration

2006-07-17
2006-01-2235
Flexible fiber-reinforced aerogel composites were studied for use as insulation materials of a future space suit for Moon and Mars exploration. High flexibility and good thermal insulation properties of fiber-reinforced silica aerogel composites at both high and low vacuum conditions make it a promising insulation candidate for the space suit application. This paper first presents the results of a durability (mechanical cycling) study of these aerogels composites in the context of retaining their thermal performance. The study shows that some of these Aerogels materials retained most of their insulation performance after up to 250,000 cycles of mechanical flex cycling. This paper also examines the problem of integrating these flexible aerogel composites into the current space suit elements.
Technical Paper

Advanced Airlock Concept Studies for Exploration Surface Systems

2006-07-17
2006-01-2234
This paper presents results of advanced airlock concept studies conducted at the NASA Johnson Space Center in support of exploration surface systems, such as lunar lander airlocks and other advanced vehicle airlocks. The studies include preliminary requirements for advanced airlocks, and rationale for using the rear-entry space suit as the basic advanced suit design to be accommodated by the airlocks. The studies also present rationale for minimum volume airlocks and gas reclamation methods needed for long duration missions. Another study shows conceptual designs for single person airlocks, dual person airlocks, and multi-person airlocks, along with associated benefits and disadvantages of each. A test and selection methodology is also discussed for future airlock development.
Technical Paper

Performance Testing of an Advanced Lightweight Freezable Radiator

2006-07-17
2006-01-2232
During extravehicular activities (EVAs) it is crucial to keep the astronaut comfortable. Currently, a sublimator rejects to space both the astronaut's metabolic heat and that produced by the Portable Life Support System. In doing so, it consumes up to 3.6 kg (8 lbm) of water; the single largest expendable during an eight-hour EVA. While acceptable for low earth orbit, resupply for moon and interplanetary missions will be too costly. Fortunately, the amount of water consumed can be greatly reduced if most of the heat load is radiated to space. However, the radiator must reject heat at the same rate that it is generated to prevent heat stroke or frostbite. Herein, we report on a freezable radiator and heat exchanger to proportionally control the heat rejection rate.
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

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

Emergency Oxygen System Evaluation for Exploration PLSS Applications

2006-07-17
2006-01-2208
The Portable Life Support System (PLSS) emergency oxygen system is being reexamined for the next generation of suits. These suits will be used for transit to Low Earth Orbit, the Moon and to Mars as well as on the surface of the Moon and Mars. Currently, the plan is that there will be two different sets of suits, but there is a strong desire for commonality between them for construction purposes. The main purpose of this paper is to evaluate what the emergency PLSS requirements are and how they might best be implemented. Options under consideration are enlarging the tanks on the PLSS, finding an alternate method of storage/delivery, or providing additional O2 from an external source. The system that shows the most promise is the cryogenic oxygen system with a composite dewar which uses a buddy system to split the necessary oxygen between two astronauts.
Technical Paper

Advanced Space Suit Portable Life Support Subsystem Packaging Design

2006-07-17
2006-01-2202
This paper discusses the Portable Life Support Subsystem (PLSS) packaging design work done by the NASA and Hamilton Sundstrand in support of the 3 future space missions; Lunar, Mars and zero-g. The goal is to seek ways to reduce the weight of PLSS packaging, and at the same time, develop a packaging scheme that would make PLSS technology changes less costly than the current packaging methods. This study builds on the results of NASA's in-house 1998 study, which resulted in the “Flex PLSS” concept. For this study the present EMU schematic (low earth orbit) was used so that the work team could concentrate on the packaging. The Flex PLSS packaging is required to: protect, connect, and hold the PLSS and its components together internally and externally while providing access to PLSS components internally for maintenance and for technology change without extensive redesign impact. The goal of this study was two fold: 1.
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

Innovative Schematic Concept Analysis for a Space Suit Portable Life Support Subsystem

2006-07-17
2006-01-2201
Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power. The PLSS concepts were evaluated using the ExtraVehicular Activity System Sizing Analysis Tool, software created by NASA to analyze integrated system mass, volume, power and thermal loads.
Technical Paper

Nanoscale Materials for Human Spaceflight Applications: Regenerable Carbon Dioxide Removal Using Single-wall Carbon Nanotubes

2006-07-17
2006-01-2195
The challenges of missions to the Moon and Mars presents NASA with the need for more advanced life support systems, including better technologies for CO2 removal in spacecraft atmospheres and extravehicular mobility units (EMU). Amine-coated single wall carbon nanotubes (SWCNT) have been proposed as a potential solution because of their high surface area and thermal conductivity. Initial research demonstrated the need for functionalization of SWCNT to obtain optimal adherence of the amine to the SWCNT support phase [1]. Recent efforts focus on the development of new methods to chemically bond amines to SWCNT. Synthesis and characterization methods for these materials are discussed and some preliminary materials characterization data are presented. The CO2 adsorption capacity for several versions of SWCNT supported amine-based CO2 scrubber materials is also determined.
Technical Paper

The Influence of Microbiology on Spacecraft Design and Controls: A Historical Perspective of the Shuttle and International Space Station Programs

2006-07-17
2006-01-2156
For over 40 years, NASA has been putting humans safely into space in part by minimizing microbial risks to crew members. Success of the program to minimize such risks has resulted from a combination of engineering and design controls as well as active monitoring of the crew, food, water, hardware, and spacecraft interior. The evolution of engineering and design controls is exemplified by the implementation of HEPA filters for air treatment, antimicrobial surface materials, and the disinfection regimen currently used on board the International Space Station. Data from spaceflight missions confirm the effectiveness of current measures; however, fluctuations in microbial concentrations and trends in contamination events suggest the need for continued diligence in monitoring and evaluation as well as further improvements in engineering systems. The knowledge of microbial controls and monitoring from assessments of past missions will be critical in driving the design of future spacecraft.
Technical Paper

System Engineering and Integration of Controls for Advanced Life Support

2006-07-17
2006-01-2121
The Advanced Integration Matrix (AIM) project at the Johnson Space Center (JSC) was chartered to study and solve systems-level integration issues for exploration missions. One of the first issues identified was an inability to conduct trade studies on control system architectures due to the absence of mature evaluation criteria. Such architectures are necessary to enable integration of regenerative life support systems. A team was formed to address issues concerning software and hardware architectures and system controls.. The team has investigated what is required to integrate controls for the types of non-linear dynamic systems encountered in advanced life support. To this end, a water processing bioreactor testbed is being developed which will enable prototyping and testing of integration strategies and technologies.
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

Standardized Radiation Shield Design Method: 2005 HZETRN

2006-07-17
2006-01-2109
Research committed by the Langley Research Center through 1995 resulting in the HZETRN code provides the current basis for shield design methods according to NASA STD-3000 (2005). With this new prominence, the database, basic numerical procedures, and algorithms are being re-examined with new methods of verification and validation being implemented to capture a well defined algorithm for engineering design processes to be used in this early development phase of the Bush initiative. This process provides the methodology to transform the 1995 HZETRN research code into the 2005 HZETRN engineering code to be available for these early design processes. In this paper, we will review the basic derivations including new corrections to the codes to insure improved numerical stability and provide benchmarks for code verification.
Technical Paper

Micrometeoroid and Orbital Debris Enhancements of Shuttle Extravehicular Mobility Unit Thermal Micrometeoroid Garment

2006-07-17
2006-01-2285
As NASA is preparing to extend man's reach into space, it is expected that astronauts will be required to spend more and more time exposed to the hazards of performing Extra-Vehicular Activity (EVA). One of these hazards includes the risk of the space suit bladder being penetrated by hypervelocity micrometeoroid and orbital debris (MMOD) particles. Therefore, it has become increasingly important to investigate new ways to improve the protectiveness of the current Extravehicular Mobility Unit (EMU) against MMOD penetration. ILC Dover conducted a NASA funded study into identifying methods of improving the current EMU protection. The first part of this evaluation focused on identifying how to increase the EMU shielding, selecting materials to accomplish this, and testing these materials to determine the best lay-up combinations to integrate into the current thermal micrometeoroid garment (TMG) design.
Technical Paper

Analysis of the Effect of Age on Shuttle Orbiter Lithium Hydroxide Canister Performance

2005-07-11
2005-01-2768
Recent efforts have been pursued to establish the usefulness of Space Shuttle Orbiter lithium hydroxide (LiOH) canisters beyond their certified two-year shelf life, at which time they are currently considered “expired.” A stockpile of Orbiter LiOH canisters are stowed on the International Space Station (ISS) as a backup system for maintaining ISS carbon dioxide Canisters with older (CO2) control. Canister with older pack dates must routinely be replaced with newly packed canisters off-loaded from the Orbiter Middeck. Since conservation of upmass is critical for every mission, the minimization of canister swap-out rate is paramount. LiOH samples from canisters with expired dates that had been returned from the ISS were tested for CO2 removal performance at the NASA Johnson Space Center (JSC) Crew and Thermal Systems Division (CTSD). Through this test series and subsequent analysis, performance degradation was established.
Technical Paper

Advanced Extravehicular Activity Education Outreach in Support of the Vision for Space Exploration

2005-07-11
2005-01-3100
The Vision for Space Exploration outlines NASA's goals to return to the Moon, and travel on to Mars. The exploration activities associated with these endeavors will include both space and surface extravehicular activities (EVAs). This paper describes the plans for education outreach activities and products related to the technological developments and challenges similar to those being addressed by the Advanced EVA (AEVA) team. Efforts to involve and coordinate educational research projects with the AEVA team will also be discussed. The proposed activities and products will provide hands-on, interactive exercises through workshops, presentations, and demonstrations to allow students of all levels to learn about and experience the design challenges similar to what NASA deals with everyday in developing EVA systems.
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