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A Novel Method for Characterizing Spacesuit Mobility through Metabolic Cost

Spacesuit mobility has historically been defined and characterized by a combination of range of motion and joint torque of the individual anatomical joints when performing isolated motions meant to drive that joint only in a given orthogonal plane. While this has been the standard approach for several decades, there are numerous shortcomings that suit designers and engineers would like to see rectified. First, the lack of a standardized method for collecting both range of motion and joint torque translates to many different test setups, procedures and methods of data analysis. Second, all of these previously used methods for data collection lack some degree of repeatability, even within the same test setup and the same conductor; in addition, attempts at higher fidelity data collection techniques require high overhead and cost with minimal improvement. Lastly, isolated motions in standard anatomical planes are not representative of real‐world tasks that a crewmember would be performing during an EVA, be it microgravity or surface exploration based. To address these shortcomings, options are being explored within the Space Suit and Crew Survival Systems Branch to ascertain the feasibility of an alternative approach to defining mobility - one that is more repeatable, lower overhead, and more tied to functional EVA tasks. This paper serves to document the first attempt at such an alternative option - one that looks at the metabolic energy‐cost of a spacesuit. In other words, can we objectively compare the mobility of a spacesuit by evaluating the metabolic cost of that suit to the wearer while performing a battery of functional EVA tasks?

McFarland, Shane

Non-Intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

Chemical sensors for monitoring gas composition, including oxygen, humidity, carbon dioxide, and trace contaminants are needed to characterize and validate spacesuit design and operating parameters. This paper reports on the first prototypes of a non-intrusive gas sensing technology based on flexible sensitive patches positioned inside spacesuit prototypes and interrogated by optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. The sensitive patches are based on luminescent materials whose emission parameters vary with the partial pressure of a specific gas. Patches sensitive to carbon dioxide, humidity, oxygen, and ammonia have been developed, and their preliminary characterization in the laboratory using Mark III-like helmet parts is described. The first prototype system consists of a four-channel fiber optic luminescent detector that can be used to monitor any of the selected target gases at four locations. To switch from one gas to another we replace the (disposable) sensor patches and adjust the system settings. Repeatability among sensitive patches and of sensor performance from location to location has been confirmed, assuring that suit engineers will have flexibility in selecting multiple sensing points, fitting the sensor elements into the spacesuit, and easily repositioning the sensor elements as desired. The evaluation of the first prototype for monitoring carbon dioxide during washout studies in a space suit prototype is presented.

Delgado, Jesus

Virtual Fit Assessment: Validation using Historical Spacesuit Fit Data

Virtual fit tests using 3D body scans have provided a cost-effective means to predictively assess spacesuit fit for the current and future astronaut population. However, fit is a complex issue influenced by physical interferences, subjective preference, and many other factors. Fit can substantially differ between the type of hardware, environmental conditions, and tasks being performed. Namely, fit changes across different contexts, such as 3D printed mockup evaluations, pressurized one-g suited test events, neutral buoyancy and other training events, and flight extravehicular activities (EVA). These challenges make it difficult to validate virtual fit frameworks to physical suit sizing. This study proposes a new method of validation using the wealth of historically archived suit fit data. Physically Assessed Fit (PAF) data was assessed from astronauts and test volunteers who wore the legacy Extravehicular Mobility Unit (EMU). The data was collected during the past decades at NASA and considered to be most reliable and dependable. Each participant was 3D scanned for body shape and spacesuit-critical dimensions were measured per NASA guidelines. The participants’ size preference for hard upper torso (HUT) assembly was retrieved from their pressurized suit fit check records. Fit assessments were also updated after one-g EVA training, neutral buoyancy training, and EVA flights. Virtually Assessed Fit (VAF) was done by overlaying the CAD model of a HUT with the 3D body scans of the PAF participants. Each body scan was iteratively adjusted for the position inside the HUT to minimize the suit-to-body contact interference while satisfying a set of prescribed requirements. Then the residual contact area, depth, and volume were quantified as VAF metrics. This process was repeated for the different HUT sizes, including medium, large, and extra-large. Statistical modeling is currently in progress and will be presented at the conference. A statistical classifier will be developed to predict a fit probability for different HUT sizes as a function of the corresponding person’s VAF metrics. The HUT size with the highest fit probability will constitute the most likely size selection for the person, and the prediction will be compared against the corresponding PAF data. The participant data will be randomly pre-grouped into either a model development or validation subset. While the model development subset will be used to build the probability model, the validation subset will be used to assess the model accuracy. Also, the locations and magnitudes of suit-body-contacts will be estimated from VAF. This information can identify the critical suit geometry and body shape features that influence suit fit. The variations found in PAF size selections by subjects with similar VAF metrics will allow for investigations into subjective preferences, for example, tight versus loose fit. Overall, this study is expected to provide a structured validation of a virtual suit fit framework, which has not been possible in the past. The outcome can also provide useful insights and potential limitations for interpreting virtual fit tests for future spacesuit designs and population accommodation.

Han Kim

Machine-learning Solution for Automatic Spacesuit Motion Recognition and Measurement from Conventional Video

Extravehicular Activity (EVA) spacesuits exhibit unique movement patterns due to their design characteristics. Mobility assessments using traditional motion capture systems are cost prohibitive and not feasible for some training conditions (e.g., simulated lunar outdoor terrain). This paper aims to present the ongoing development of machine learning solutions to quantify suit motions from conventional videos without special sensors or hardware. Given the fast growth in deep/machine learning technologies, external expertise was sought from open-source communities. This was expected to accelerate development and provide more cost-effective, time-saving solutions. This work was selected for a NASA Crowdsourcing project through an agency-wide solicitation. Partnerships were formed with the NASA JSC Center of Excellence for Collaborative Innovation and an execution crowdsourcing platform partner to solicit framework developments from external contenders. NASA provided contenders with video clips of spacesuits and simultaneously measured motion capture data during EVA simulation tasks. The contenders used this data to train and develop generalized algorithms to predict motions. At the end of the crowdsourcing event, five solutions were selected from 250 submissions. Each submission was tested and scored using video clips not previously disclosed to the contenders. The scoring metrics measured how well the algorithm detected the suit shape, the 2D suit joint detection accuracy, and 3D joint detection accuracy. The winning solution was able to achieve roughly 85% prediction accuracy (weighted combination of scoring metrics). Overall, the algorithms could efficiently detect various types of spacesuits and motions across different EVA simulation environments such as the Neutral Buoyancy Lab (NBL). However, 3D joint identification is less reliable when parts of the suit were obstructed in the image. After continued improvements and validation, the fully developed system will enable EVA stakeholders to quantify suit kinematic patterns, which can help optimize suit, hardware, and task designs.

Linh Vu

Machine-learning Solution for Automatic Spacesuit Motion Recognition and Measurement from Conventional Video

Extravehicular Activity (EVA) spacesuits exhibit unique movement patterns due to their design characteristics. Mobility assessments using traditional motion capture systems are cost prohibitive and not feasible for some training conditions (e.g., simulated lunar outdoor terrain). This paper aims to present the ongoing development of machine learning solutions to quantify suit motions from conventional videos without special sensors or hardware. Preliminary work into this field was promising but given the fast growth in deep/machine learning technologies, external expertise was sought from open-source communities. Partnerships were formed with the NASA JSC Center of Excellence for Collaborative Innovation (CoCEI) and an execution crowdsourcing platform partner to solicit machine learning framework developments from external contenders. NASA provided contenders with images and video clips of spacesuits with simultaneously measured motion capture data during EVA simulation tasks. The contenders used this data to train and develop generalized algorithms to predict motions. At the end of the crowdsourcing event, the top five solutions were selected from 250 submissions. Each submission was tested and scored using video clips not previously disclosed to the contenders. The weighted scoring metrics measured how well the algorithm detected the suit shape, the 2D suit joint detection accuracy, and 3D joint detection accuracy. The winning solution was able to achieve roughly 85% prediction accuracy. Overall, the algorithms could efficiently detect various types of spacesuits and motions across different EVA environments such as the NASA Active Response Gravity Offload System (ARGOS). After continued improvements and validation, the fully developed system will enable EVA stakeholders to quantify suit kinematic patterns, which can help optimize suit, hardware, and task designs.

Linh Vu

Advanced Technology Infusion into Spacesuit Systems

Advancement in technology drives our future. The successful implementation of a technology drives its possibilities. The National Aeronautics and Space Administration (NASA) has invested in numerous technologies that have proved to be successful. The desire is to learn from those successes. For a technology to evolve, become a reality, and infuse into NASA’s missions, a compilation of success-oriented factors must exist for the technology to reach fruition. Understanding these factors could help decrease the complexity of technology infusion and bridge the gap between technology developers and system integrators. The knowledge gained could facilitate the design, development, test, and infusion of a technology to be more effective and efficient. Successful technology infusion is complex and can be even more daunting when advanced technologies are infused into complicated systems. NASA, industry, and academia desire to understand the infusion process, along with measuring the success of infusing an advanced technology into a complex system. This paper focuses on complicated systems that necessitate successful infusion of technologies. These systems include NASA’s spacesuits used for extravehicular activity, including the Apollo Extravehicular Mobility Unit (EMU), the Shuttle/International Space Station EMU, and the Exploration EMU (xEMU) architectures. Several life support technologies will be addressed in the xEMU. Those technologies will be discussed, along with a methodology for assessing infusion pathways. The infusion pathways of these life support technologies into spacesuit architectures can form the benchmark for technology infusion into other architectures for lunar and Martian surfaces. The spacesuit system architectures as case studies can provide the foundation of technical knowledge to help NASA and industry’s project managers and system managers integrate advanced technologies more effectively and efficiently.

Cinda Chullen

Investigating Abrasion Effects of Lunar Simulant Grain Sizes on Candidate Spacesuit Fabric

Lunar dust is identified as one of the most significant challenges during the Apollo exploration missions due to its extremely abrasive and electrostatic characteristics. As NASA and the space industry prepare for the upcoming Artemis missions, researching and testing with lunar simulant is quintessential to understanding the effects of lunar dust on the systems and equipment that will be deployed on the lunar surface. Testing will also provide paths that lead to developing technologies and cleaning tools that could be used for dust mitigation. Additionally, it is expected that any hardware that will be exposed to the dusty environment should undergo rigorous testing to ensure it will maintain long-term performance and operate on the lunar surface. For this study, exterior spacesuit fabric was observed. Abrasion is one of the main concerns of lunar dust exposure for spacesuit fabric. Three different abrasion methods were chosen: a rotary tumbler, the Martindale method, and Accelerotor. These abrasion methods were tested on coated and uncoated spacesuit material, Orthofabric, to understand the abrasion rates of sieved lunar simulant and investigate if the addition of ceramic coating mitigated dust abrasion. To summarize, the testing results provided that larger grains are more abrasive than smaller grains, and the selected ceramic coatings did not minimize abrasion during the controlled abrasion tests. It is important to note that the selected ceramic coatings were not designed or intended to provide protection from the abrasive lunar environment. It is recommended to select additional ceramic coatings with an elevated TRL of 5 or greater for testing with Orthofabric and lunar simulant. As an additional note, contact angle measurements were not accounted for in coating selection and should be a factor when selecting adhesion resistant coatings for lunar dust.

grain size

EVA SPACESUIT INCIDENCE TRACKING

INTRODUCTION: Extravehicular Activity (EVA)suit-related injuries to crew during training and inflight operations are not uncommon. Systematic tracking of these issues has waxed and waned throughout NASA’s history. Given two new EVA suits in development and an increase in EVA training, the need for dutiful recording of this data is critical. The Suited User Incident Tracking System (SUITS) was developed in the last decade to track all suited exposures, recording exposure details and any related issues, pains, or injuries that arise. METHODS: SUITS data collected from 2017 to 2022 was analyzed for issue frequency and severity for each body location and plotted to visualize where issues were occurring. Clustering techniques using a k-modes approach were also applied to the data set to generate profiles of populations that experienced issues in the suit, and populations that did not. RESULTS:A key finding from SUITS is that discomfort and pain observed in the new planetary spacesuits are occurring in new body locations than those experienced in the microgravity space suit (Extravehicular Mobility Unit (EMU)).To date, the lower body and torso regions account for most pain reports in planetary spacesuits whereas most reports in EMU were shoulders and hands. DISCUSSION:SUITS will continue to be used to capture exposures for all suit types. As training suit availability improves and training cadence increases in preparation for planetary missions, it is critical to capture and assess all suit incidences. Further, a Suited Anomaly Assessment Team (SAAT) consisting of a broad range of EVA stakeholders was formed to share and act on SUITS data with the goal of developing robust solutions to issues/injuries as they arise. Understanding the types and locations of injuries that occur during suited operations will help inform future work related to EVA fitness training requirements, suit design, and modeling efforts to avoid injury. LEARNING OBJECTIVES: 1. Systematic tracking of suited exposures and issues is critical for understanding the complex interaction between the human and the EVA spacesuit. 2. As EVA suit issues/injuries arise it is important to share that data with a broad group to ensure robust strategies are developed.

N Newby

Exploring the Moon: Preserving the Legacy Through Spacesuit Knowledge Capture and Strategic Communication

NASA is returning to the Moon to stay. To establish a sustained lunar presence, astronauts will pack spacesuits, surface-mobility tools, rovers, and decades’ worth of knowledge. The U.S. Spacesuit Knowledge Capture (SKC) and Strategic Communications (Strat Comm) team is specialized in capturing, preserving, and sharing space-related knowledge with NASA scientists, technicians, engineers, vendors, and the public to support space exploration. Since the SKC Program’s 2007 inception, its focus has been to capture and share valuable spacesuit-related knowledge with the NASA community. As the program evolved, its notoriety, funding, scope, and staffing expanded from a one-person, part-time, unfunded operation to a small-team, funded entity. Currently, this team has been formulated with a diverse skillset to meet the requirements of its stakeholders. The SKC and Strat Comm team has used its skills to produce over 260 recorded knowledge captures of subject-matter experts (SMEs) and photoshoots. These knowledge captures are in the form of photographs, lectures, workshops, vignettes, videos, and interviews containing essential space-related knowledge. To help educate the space community and public, this trove of information (e.g., videos of world-class facilities, photographs, and SME lectures), produced inside NASA Johnson Space Center, can be obtained through various sources. During Fiscal Year 2024, the SKC and Strat Comm team will focus on several initiatives. Examples of initiatives include the following: 1) share lessons learned during NASA’s internal venues such as Safety & Health Day and Day of Remembrance; 2) share knowledge with the public, educators, and students through a media production titled Exploring the Moon; and 3) highlight NASA’s unique capabilities and expertise in a video series titled What’s Behind This Door? This paper discusses the team's approach, unique capture capability, initiatives, and much more.

Cinda Chullen

Wire-break Ignition Testing of Materials for Spacesuit Fire Hazard Control

The input design constraints applied to the extravehicular activity (EVA) spacesuit pose a significant challenge for mitigation of fire hazards. To minimize fatigue and increase comfort of the crewmember operating the suit, the suit pressure is lowered below sea level conditions with typical EVA suit designs operating with 4.3 psia (29.7 kPa). With the lowered operating pressures and the use of closed-loop life support, the suit requires elevated concentrations of oxygen, typically >95%. At these oxygen concentrations, nearly the entirety of the suit internal materials are flammable. This leaves one remaining possible control leg of the fire triangle: ignition sources. Since the Gemini and Apollo programs, this has been a risk that has undergone constant reassessment, with a focus on improved mitigation. After the Apollo I fire, an arc ignition method was developed and used to quantify ignition thresholds for in-suit materials resulting in a current limit for powered in-suit devices applied to all subsequent suit designs. After the discovery of a frayed spacesuit biomed cable on STS-113 during the Shuttle Program, the previous arcing method was repeated with additional methods developed to extend the testing further. One of those methods was wire-break ignition testing, in which the current in a single strand of wire was progressively increased, preheating the material in proximity with a resultant break and the application of a reasonably repeatable arc to ignite the material, all while exposed in the selected environment. This method was used to test a suite of spacesuit materials providing relative performance with respect to ignition with this configuration for application of energy. This paper discusses extension of the current data set to address recent material additions, lowering of energy test levels for quantification of materials too low to measure in previous testing, as well as future plans to improve this method.

Colin Campbell

Exploring the Moon: Preserving the Legacy Through Spacesuit Knowledge Capture and Strategic Communication

NASA is returning to the Moon to stay. To establish a sustained lunar presence, astronauts will pack spacesuits, surface-mobility tools, rovers, and decades’ worth of knowledge. The U.S. Spacesuit Knowledge Capture (SKC) and Strategic Communications (Strat Comm) team is specialized in capturing, preserving, and sharing space-related knowledge with NASA scientists, technicians, engineers, vendors, and the public to support space exploration. Since the SKC Program’s 2007 inception, its focus has been to capture and share valuable spacesuit-related knowledge with the NASA community. As the program evolved, its notoriety, funding, scope, and staffing expanded from a one-person, part-time, unfunded operation to a small-team, funded entity. Currently, this team has been formulated with a diverse skillset to meet the requirements of its stakeholders. The SKC and Strat Comm team has used its skills to produce over 260 recorded knowledge captures of subject-matter experts (SMEs) and photoshoots. These knowledge captures are in the form of photographs, lectures, workshops, vignettes, videos, and interviews containing essential space-related knowledge. To help educate the space community and public, this trove of information (e.g., videos of world-class facilities, photographs, and SME lectures), produced inside NASA Johnson Space Center, can be obtained through various sources. During Fiscal Year 2024, the SKC and Strat Comm team will focus on several initiatives. Examples of initiatives include the following: 1) share lessons learned during NASA’s internal venues such as Safety & Health Day and Day of Remembrance; 2) share knowledge with the public, educators, and students through a media production titled Exploring the Moon; and 3) highlight NASA’s unique capabilities and expertise in a video series titled What’s Behind This Door? This paper discusses the team's approach, unique capture capability, initiatives, and much more.

Cinda Chullen

Spacesuit Sizing by Multivariate Simulation: Case Study for Liquid Cooling and Ventilation Garment

A technique was developed to assess the fit of spacesuit garment liquid cooling and ventilation garment (LCVG). A fit scoring scheme was built from the spacesuit sizing requirements and guidelines, and the accommodated proportion of the wearer population was estimated from statistically synthesized pseudo population data. The method evaluated different scenarios of LCVG sizing systems including 1) baseline 7-size system, 2) 7-sizes with target body dimensions iteratively adjusted for maximum fit, and 3) 9-sizes with iterative adjustments. Overall, the baseline sizing system showed 81% accommodation rate, while the hypothetical new systems in-tegrating iterative adjustments for 7- and 9-sizes predictively indicated that accommodation could improve up to 92 and 97%. The proposed method provided a structured metric to quantify fit performance of a garment sizing system, which can be further applied to different spacesuit component, PPE and garment designs.

Han Kim

Advanced Technology Infusion into a Spacesuit System

Advancement in technology drives our future. Moreover, the successful implementation of a technology drives its possibilities. The National Aeronautics and Space Administration (NASA) has invested in numerous technologies over the decades. A quote from NASA’s Space Technology Mission Directorates indicates the importance of technology: “Historically, technology has driven humanity’s progress and will continue to define our future. Our nation chooses to invest in new technology not only to maintain our edge in the global economy but also because technology helps us: Redefine the possible; Create a technologically advanced future; and Drive economic growth.” It is difficult for a technology to satisfy these goals unless it can be successfully infused into a system. For a technology to continue to evolve, become a reality, and infuse into NASA’s missions, there must exist a compilation of success-oriented factors for the technology to reach fruition. Understanding these factors could help decrease the complexity of technology infusion and bridge the gap between technology developers and system integrators. Ultimately, the knowledge gained could facilitate the design, development, and infusion of a technology to be more effective and efficient. Successful technology infusion is complex. Even complexity at the interfaces can be daunting when advanced technology’s infuse into complex systems such as a spacesuit. Additionally, unforeseen emergent behavior and challenges can surface upon integration. Overall, there is a need to understand and measure the success of infusing an advanced technology into a complex system. Industry and academia desire to quantify performance benefits of technologies integrated into complex systems. This paper will focus advanced technology infusion into a spacesuit system. This research could help NASA and industry’s project managers and system mangers integrate advanced technologies more effectively and efficiently.

Advanced Technology

Development of a zero-prebreathe spacesuit

This paper presents the results of a program to develop an improved high pressure (zero-prebreathe) spacesuit utilizing the latest joint technology as well as materials and processes which are consistent with the space environment and suit production techniques. Other development objectives include: longer life, lower joint torques with increased ranges, improved reproducibility and reliability, facilitated resizing ability and increased overall performance capability when compared to the present Shuttle Orbiter Spacesuit at the higher pressures.

Flugel, C. W.

Development of a zero-prebreathe spacesuit

This paper presents the results of a program to develop an improved high pressure (zero-pre-breathe) spacesuit utilizing the latest joint technology as well as materials and processes which are consistent with the space environment and suit production techniques. Other development objectives include: longer life, lower joint torques with increased ranges, improved reproducibility and reliability, facilitated resizing ability and increased overall performance capability when compared to the present Shuttle Orbiter Spacesuit at the higher pressures.

Rayfield, J. F.

Astronaut Exposures to Ionizing Radiation in a Lightly-Shielded Spacesuit

The normal working and living areas of the astronauts are designed to provide an acceptable level of protection against the hazards of ionizing radiation of the space environment. Still there are occasions when they must don a spacesuit designed mainly for environmental control and mobility and leave the confines of their better-protected domain. This is especially true for deep space exploration. The impact of spacesuit construction on the exposure of critical astronaut organs will be examined in the ionizing radiation environments of free space, the lunar surface and the Martian surface. The computerized anatomical male model is used to evaluate astronaut self-shielding factors and to determine space radiation exposures to critical radiosensitive human organs.

Wilson, J. W.

Shuttle Spacesuit (Radiation) Model Development

A detailed spacesuit computational model is being developed at the Langley Research Center for exposure evaluation studies. The details of the construction of the spacesuit are critical to an estimate of exposures and for assessing the health risk to the astronaut during extravehicular activity (EVA). Fine detail of the basic fabric structure, helmet, and backpack is required to assure a valid evaluation. The exposure fields within the Computerized Anatomical Male (CAM) and Female (CAF) are evaluated at 148 and 156 points, respectively, to determine the dose fluctuations within critical organs. Exposure evaluations for ambient environments will be given and potential implications for geomagnetic storm conditions discussed.

Anderson, Brooke M.

Design and Testing of Improved Spacesuit Shielding Components

In prior studies of the current Shuttle Spacesuit (SSA), where basic fabric lay-ups were tested for shielding capabilities, it was found that the fabric portions of the suit give far less protection than previously estimated due to porosity and non-uniformity of fabric and LCVG components. In addition, overall material transmission properties were less than optimum. A number of alternate approaches are being tested to provide more uniform coverage and to use more efficient materials. We will discuss in this paper, recent testing of new material layups/configurations for possible use in future spacesuit designs.

Ware, J.