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1.
Aerosp Med Hum Perform ; 93(8): 643-648, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-36050859

RESUMO

INTRODUCTION: Heel-lift is a subjectively reported fit issue in planetary spacesuit boot prototypes that has not yet been quantified. Inertial measurement units (IMUs) could quantify heel-lift but are susceptible to integration drift. This work evaluates the use of IMUs and drift-correction algorithms, such as zero-velocity (ZVUs) and zero-position updates (ZPUs), to quantify heel-lift during spacesuited gait.METHODS: Data was originally collected by Fineman et al. in 2018 to assess lower body relative coordination in the spacesuit. IMUs were mounted on the spacesuit lower legs (SLLs) and spacesuit operator's shank as three operators walked on a level walkway in three spacesuit padding conditions. Discrete wavelet transforms were used to identify foot-flat phase and heel-off for each step. Differences in heel-off timepoints were calculated in each step as a potential indicator of heel-lift, with spacesuit-delayed heel-off suggesting heel-lift. Average drift rates were estimated prior to and after applying ZVUs and ZPUs.RESULTS: Heel-off timepoint differences showed instances of spacesuit-delayed heel-off and instances of operator-delayed heel-off. Drift rates after applying ZVUs and ZPUs suggested an upper time bound of 0.03 s past heel-off to measure heel-lift magnitude with an accuracy of 1 cm.DISCUSSION: Results suggest that IMUs may not be appropriate for quantifying the presence and magnitude of heel lift. Operator-delayed heel-off suggests that the SLL may be expanding prior to heel-off, creating a false vertical acceleration signal interpreted by this study to be spacesuit heel-off. Quantifying heel-off will therefore require improvements in IMU mounting to mitigate the effects of SLL, or alternative sensor technologies.Boppana A, Priddy ST, Stirling L, Anderson AP. Challenges in quantifying heel-lift during spacesuit gait. Aerosp Med Hum Perform. 2022; 93(8):643-648.


Assuntos
Calcanhar , Trajes Espaciais , Fenômenos Biomecânicos , , Marcha , Humanos , Caminhada
2.
Hum Factors ; 64(4): 649-661, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-33121286

RESUMO

OBJECTIVE: To better study human motion inside the space suit and suit-related contact, a multifactor statistical model was developed to predict torso body shape changes and lumbar motion during suited movement by using fabric strain sensors that are placed on the body. BACKGROUND: Physical interactions within pressurized space suits can pose an injury risk for astronauts during extravehicular activity (EVA). In particular, poor suit fit can result in an injury due to reduced performance capabilities and excessive body contact within the suit during movement. A wearable solution is needed to measure body motion inside the space suit. METHODS: An array of flexible strain sensors was attached to the body of 12 male study participants. The participants performed specific static lumbar postures while 3D body scans and sensor measurements were collected. A model was created to predict the body shape as a function of sensor signal and the accuracy was evaluated using holdout cross-validation. RESULTS: Predictions from the torso shape model had an average root mean square error (RMSE) of 2.02 cm. Subtle soft tissue deformations such as skin folding and bulges were accurately replicated in the shape prediction. Differences in posture type did not affect the prediction error. CONCLUSION: This method provides a useful tool for suited testing and the information gained will drive the development of injury countermeasures and improve suit fit assessments. APPLICATION: In addition to space suit design applications, this technique can provide a lightweight and wearable system to perform ergonomic evaluations in field assessments.


Assuntos
Trajes Espaciais , Astronautas , Desenho de Equipamento , Ergonomia , Atividade Extraespaçonave , Humanos , Região Lombossacral , Masculino
3.
Aerosp Med Hum Perform ; 92(4): 231-239, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33752786

RESUMO

INTRODUCTION: Research has shown that astronauts performing extravehicular activities may be exposed, under certain conditions, to undesired electrical hazards. This study used computer models to determine whether these undesired induced electrical currents could be responsible for involuntary neuromuscular activity caused by either large diameter peripheral nerve activation or reflex activity from cutaneous afferent stimulation.METHODS: A multiresolution variant of the admittance method along with a magnetic resonance image millimeter resolution model of a male human body were used to calculate the following: 1) induced electric fields; 2) resistance between contact areas in a Extravehicular Mobility Unit spacesuit; 3) currents induced in the human body; 4) the physiological effects of these electrical exposures; and 5) the risk to the crew during extravehicular activities.RESULTS: Using typical EMU shock exposure conditions, with a 15V source, the current density magnitudes and total current injected are well above previously reported startle reaction thresholds. This indicates that, under the considered conditions during a spacewalk in the charged ionospheric plasma of space, astronauts could experience possibly harmful involuntary motor response and sensory pain nerve activation.Hamilton DR. Electrical shock hazard severity estimation during extravehicular activity for the International Space Station. Aerosp Med Hum Perform. 2021; 92(4):231239.


Assuntos
Voo Espacial , Trajes Espaciais , Astronautas , Simulação por Computador , Atividade Extraespaçonave/efeitos adversos , Humanos , Masculino , Trajes Espaciais/efeitos adversos
4.
J Hosp Infect ; 108: 55-63, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33122042

RESUMO

The coronavirus disease 2019 pandemic has meant that there is growing pressure on hospital resources, not least the availability of appropriate personal protective equipment (PPE), particularly face masks and respirator masks. Within the field of orthopaedic surgery, it is a common sight to see surgeons wearing 'space suits' (SSs) which comprise a helmet, hood and surgical gown. In this study, the authors made modifications to two different SS systems to incorporate a high-efficiency particulate air (HEPA) filter into the fan inlet to assess their potential as re-usable PPE systems for surgeons with regard to protection from a virus spread via respiratory droplets. The testing was carried out using particle counters upstream and downstream on a mannequin wearing two different SS systems with and without modifications to the fan inlet. The results show that using a layer of HEPA filter, cut to size and sealed to the fan inlet in the helmet, will reduce downstream particulates at the user's mouth by >99.5%; this is equivalent to a respirator mask. HEPA filter material is relatively cheap and can be used repeatedly, making this a viable alternative to disposable, and even resterilized, respirator masks in the setting of a respiratory-droplet-spread viral pandemic.


Assuntos
COVID-19/transmissão , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Procedimentos Ortopédicos/normas , Equipamento de Proteção Individual/provisão & distribuição , Filtros de Ar/estatística & dados numéricos , Filtros de Ar/tendências , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/virologia , Dispositivos de Proteção da Cabeça , Humanos , Manequins , Máscaras , Procedimentos Ortopédicos/estatística & dados numéricos , Material Particulado/análise , Projetos Piloto , Dispositivos de Proteção Respiratória/estatística & dados numéricos , Dispositivos de Proteção Respiratória/tendências , SARS-CoV-2/genética , Trajes Espaciais/tendências , Trajes Espaciais/virologia
5.
Comput Methods Biomech Biomed Engin ; 24(8): 831-843, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33337914

RESUMO

Advanced SSAs (e.g., the Mark III (MKIII)) were designed to increase mobility by eliminating the volume change associated with bending joints by using constant-volume rigid components with bearings connecting these components. Even with these changes, there are added torques required by the operator to drive the motion, which increases the energy expenditure with respect to unsuited motion. Part of the added effort stems from the mass and inertia of the suit, as well as frictional resistances to motion. This research considers the relationship between joint torques that an operator must generate and the resulting flexion/extension of the hip bearing assembly. A computational dynamics model of the MKIII inclusive of inertial and bearing friction properties was created and sensitivities of the model to input parameters (e.g., applied force, direction of gravity, bearing friction magnitude, knee angle) were investigated. The model was configured to match previously collected benchtop experimental suit data without a human that was externally forced. The model captured the hysteretic behaviour and estimated about 80% of the mean hip angle range as compared to the experimental data. Decreasing bearing resistance increased alignment with the experimental data. The torque due to inertia and friction each had periods where they dominated the total torque, supporting the importance of minimizing both mass and bearing friction. The present effort also highlighted how external forces and boundary conditions affected peak hip flexion/extension. Future efforts can use these types of dynamics models to examine motions driven internally by a person to achieve specific motions.


Assuntos
Articulação do Quadril/fisiologia , Quadril/fisiologia , Articulação do Joelho/fisiologia , Joelho/fisiologia , Trajes Espaciais , Torque , Fenômenos Biomecânicos , Simulação por Computador , Desenho de Equipamento , Fricção , Humanos , Teste de Materiais , Fenômenos Mecânicos , Movimento (Física) , Amplitude de Movimento Articular
6.
IISE Trans Occup Ergon Hum Factors ; 9(3-4): 134-142, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34605376

RESUMO

OCCUPATIONAL APPLICATIONSBiomechanical risk factors associated with spacesuit manual material handling tasks were evaluated using the singular value decomposition (SVD) technique. SVD analysis decomposed each lifting tasks into primitive motion patterns called eigenposture progression (EP) that contributed to the overall task. Biomechanical metrics, such as total joint displacement, were calculated for each EP. The first EP (a simultaneous knee, hip, and waist movement) had greater biomechanical demands than other EPs. Thus, tasks such as lifting from the floor were identified as "riskier" by having a greater composition of the first EP. The results of this work can be used to improve a task as well as spacesuit design by minimizing riskier movement patterns as shown in this case study. This methodology can be applied in civilian occupational settings to analyze open-ended tasks (e.g., complex product assembly and construction) for ergonomics assessments. Using this method, worker task strategies can be evaluated quantitatively, compared, and redesigned when necessary.


TECHNICAL ABSTRACTBackground Astronauts will perform manual materials handling tasks during future Lunar and Martian exploration missions. Wearing a spacesuit will change lifting kinematics, which could lead to increased musculoskeletal stresses. Thus, it is important to understand how suited motion patterns affect injury risk.Purpose The objective of this study was to use the singular value decomposition (SVD) technique to assess movement differences between lifting techniques in a spacesuit with respect to biomechanical risk factors.Methods Joint angles were derived from motion capture data of lifting tasks performed in the MK-III spacesuit. SVD was performed on the joint angles, extracting the common patterns ("eigenposture progressions") across each task and their weightings as a function of time. Biomechanical risk factors such as total joint displacement, moments at the low back waist joint, and stability metrics were calculated for each eigenposture progression (EP). These metrics were related back to each task and compared.Results The resulting EPs represented characteristic motions that composed each task. For example, the first eigenposture progression (EP1) was identified as waist, hip, and knee motions and the second eigenposture progression (EP2) was described as arm motions. EPs were coupled with different levels of biomechanical stresses, such that EP1 resulted in the greatest amount of joint displacement and low back moment compared to the other EPs. Tasks such as lifting from the floor were identified as "riskier" due to a higher composition of EP1. Differences in EP weightings were also observed across subjects with varying levels of suited experience.Conclusions The linear factorial analysis, combined with biomechanical stress variables, demonstrated an easy and consistent approach to assess injury risk by relating risk to derived EPs and motions. As shown in the lifting analysis and case study example, suited movement strategies or interventions that minimize "riskier" EPs and reduce injury risk were identified. With further development, a future analysis of relevant suited actions can inform mission and suit design.


Assuntos
Remoção , Trajes Espaciais , Fenômenos Biomecânicos , Ergonomia , Humanos , Análise e Desempenho de Tarefas
7.
Aerosp Med Hum Perform ; 91(12): 923-931, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33243335

RESUMO

BACKGROUND: NASA has been making efforts to assess the carbon dioxide (CO2) washout capability of spacesuits using a standard CO2 sampling protocol. This study established the methodology for determining the partial pressure of inspired CO2 (PIco2) in a pressurized spacesuit. We applied the methodology to characterize PIco2 for the extravehicular mobility unit (EMU).METHODS: We suggested an automated and mathematical algorithm to find the end-tidal CO2 and the end of inspiration. We provided objective and standardized guidelines to identify acceptable breath traces, which are essential to accurate and reproducible calculation of the in-suit inhaled and exhaled partial pressure of CO2 (Pco2). The mouth guard-based method for measurement of inhaled and exhaled dry-gas Pco2 was described. We calculated all individual concentrations of PIco2 inhaled by 19 healthy subjects classified into 3 fitness groups. The transcutaneous Pco2 was monitored as a secondary measure to validate washout performance.RESULTS: Mean and standard deviation values for the data collection performance and the CO2 metrics were presented (e.g., minimum time weighted average Pco2 at suited workloads of resting, 1000, 2000, and 3000 (BTU h1) were 4.75 1.03, 8.09 1.39, 11.39 1.26, and 14.36 1.29 (mmHg s1). All CO2 metrics had a statistically significant association and all positive slopes with increasing metabolic rate. No significant differences in CO2 metrics were found between the three fitness groups.DISCUSSION: A standardized and automated methodology to calculate PIco2 exposure level is presented and applied to characterize CO2 washout in the EMU. The EMU has been operated successfully in over 400 extravehicular activities (EVAs) and is considered to provide acceptable CO2 washout performance. Results provide a basis for establishing verifiable Pco2 requirements for current and future EVA spacesuits.Kim KJ, Bekdash OS, Norcross JR, Conkin J, Garbino A, Fricker J, Young M, Abercromby AFJ. The partial pressure of inspired carbon dioxide exposure levels in the extravehicular mobility unit. Aerosp Med Hum Perform. 2020; 91(12):923931.


Assuntos
Dióxido de Carbono , Trajes Espaciais , Atividade Extraespaçonave , Humanos , Pressão Parcial
8.
Aerosp Med Hum Perform ; 91(12): 956-961, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33243339

RESUMO

INTRODUCTION: Hypergolic propellants can be released in large amounts during space launch contingencies. Whether propellant-contaminated suit fabric poses a significant risk to rescue crews, due to off-gassing, has not been explored in detail. In this study, we addressed this issue experimentally, exposing space suit fabric to propellants (dinitrogen tetroxide [N2O4] and monomethyl hydrazine [MMH]).METHODS: The NASA Space Shuttle Program Advanced Crew Escape System II (ACES II) is similar to the NASA Orion Crew Survival System (OCSS) and was utilized here. Suit fabric was placed and sealed into permeation cells. Fabric exterior surface was exposed to constant concentrated hypergolics, simulating permeation and leakage. Fabric was rinsed, and permeation and off-gassing kinetics were measured. Experimental parameters were selected, simulating suited flight crewmembers during an evacuation transport without cabin air flow.RESULTS: The fabric allows for immediate permeation of liquid or vaporized MMH and N2O4. NO2 off-gassing never exceeded the AEGL-1 8-h level (acute exposure guideline level). In contrast, MMH off-gassing levels culminated in peak levels, approaching AEGL-2 10-min levels, paralleling the drying process of the fabric layers. DISCUSSION: Our findings demonstrate that MMH off-gassing is promoted by the drying of suit material in a delayed fashion, resulting in MMH concentrations having the potential for adverse health effects for flight and rescue crews. This indicates that shorter decontamination times could be implemented, provided that suit material is either kept moist to prevent off-gassing or removed prior to medical evacuation. Additional studies using OCSS or commercial crew suits might be needed in the future.Schwertz H, Roth LA, Woodard D. Propellant off-gassing and implications for triage and rescue. Aerosp Med Hum Perform. 2020; 91(12):956961.


Assuntos
Voo Espacial , Trajes Espaciais , Gases , Astronave , Triagem
10.
Eur J Appl Physiol ; 119(7): 1633-1648, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31069517

RESUMO

PURPOSE: To identify strength and performance thresholds below which task performance is impaired. METHODS: A new weighted suit system was used to manipulate strength-to-body-weight ratio during the performance of simulated space explorations tasks. Statistical models were used to evaluate various measures of muscle strength and performance on their ability to predict the probability that subjects could complete the tasks in an acceptable amount of time. Thresholds were defined as the point of greatest change in probability per change in the predictor variable. For each task, median time was used to define the boundary between "acceptable" and "unacceptable" completion times. RESULTS: Fitness thresholds for four space explorations tasks were identified using 23 physiological input variables. Area under receiver operator characteristic curves varied from a low of 0.68 to a high of 0.92. CONCLUSION: An experimental analog for altering strength-to-body weight combined with a probability-based statistical model for success was suitable for identifying thresholds for task performance below which tasks could either not be completed or time to completion was unacceptably high. These results provide data for strength recommendations for exploration mission ambulatory task performance. Furthermore, the approach can be used to identify thresholds for other areas where occupationally relevant tasks vary considerably.


Assuntos
Força Muscular , Desempenho Físico Funcional , Trajes Espaciais/normas , Desempenho Profissional/normas , Adulto , Feminino , Humanos , Masculino , Resistência Física , Trajes Espaciais/efeitos adversos
11.
Aerosp Med Hum Perform ; 90(6): 553-565, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31101141

RESUMO

INTRODUCTION: Although a space suit is a technological feat sustaining human life outside the spacecraft, working in the space suit environment can lead to musculotendon and soft tissue injuries in astronauts. In this literature review, we consider the injury risk mechanisms for human-space suit interactions. We first present a review of space suit injury risk founded in empirical, statistical, and experimental studies. We then review efforts in computational modeling of a human and space suit. As the interpretation of models for injury risk has not previously been defined, a review is presented of biomechanical considerations of injury risk to the tissue and joints based on previously observed space suit injuries. A review of risk assessment in occupational health in the workplace is then presented, an adjacent area that informs relevant measures of consideration for human-space suit applications. Finally, we discuss how the work-to-date can inform continued efforts in minimizing risk of musculoskeletal injury to the human when using a space suit. From the literature, this review concludes space suits cause biomechanical alterations, inducing musculoskeletal injury. Combining occupational health kinematic constraints with computational models could enable a trade space evaluation on space suited biomechanics to reduce risk mechanisms. Future work, though, is required to enable computational models to be predictive of individual injury risk. Our findings show there are significant gaps in our current knowledge on tissue injuries that preclude biomechanical models from being used directly as an injury risk assessment model. This review identifies how risk factor monitoring and modeling will enable improved space suit design and evaluation.Stirling L, Arezes P, Anderson A. Implications of space suit injury risk for developing computational performance models. Aerosp Med Hum Perform. 2019; 90(6):553-565.


Assuntos
Simulação por Computador , Desenho de Equipamento/métodos , Atividade Extraespaçonave/efeitos adversos , Trajes Espaciais/efeitos adversos , Ferimentos e Lesões/prevenção & controle , Astronautas , Fenômenos Biomecânicos , Humanos , Sistema Musculoesquelético/lesões , Ferimentos e Lesões/etiologia
12.
Radiat Prot Dosimetry ; 183(1-2): 228-232, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30521032

RESUMO

Personal radiation shielding is likely to play an important role in the strategy for radiation protection of future manned interplanetary missions. There is potential for the successful adoption of wearable shielding devices, readily available in case of accidental exposures or used for emergency operations in low-shielded areas of the habitat, particularly in case of solar particle events (SPEs). Based on optimization of available resources, conceptual models for radiation protection spacesuits have been proposed, with elements made of different materials, and the first prototype of a water-fillable garment was designed and manufactured in the framework of the PERSEO project, funded by the Italian Space Agency, leading to the successful test of such prototype for ease of use and wearability on-board the International Space Station. We present results of Monte Carlo calculations offering a proof-of-principle validation of the shielding efficacy of such prototype in different SPE environments and shielding conditions.


Assuntos
Astronautas , Radiação Cósmica/efeitos adversos , Lesões por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Voo Espacial , Trajes Espaciais/normas , Relação Dose-Resposta à Radiação , Humanos , Itália , Modelos Teóricos , Método de Monte Carlo , Estudo de Prova de Conceito , Doses de Radiação , Atividade Solar
13.
Soft Robot ; 6(1): 21-37, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30457930

RESUMO

Human exploration of the Solar System is one of the most challenging objectives included in the space programs of the most important space agencies in the world. Since the Apollo program, and especially with the construction and operation of the International Space Station, extravehicular activities (EVA) have become an important part of space exploration. This article presents a soft hand exoskeleton designed to address one of the problems that astronauts face during spacewalks: hand fatigue caused by the pressurized EVA gloves. This device will reduce the stiffness of the spacesuit glove by counteracting the force exerted by the pressurized glove. To this end, the system makes use of a set of six flexible actuators, which use a shape memory alloy (SMA) wire as the actuating element. SMAs have been chosen because some of their features, such as low volume and high force-to-weight ratio, make them a suitable choice taking into account the constraints imposed by the use of the device in a spacesuit. Besides describing the different mechanical and electronic subsystems that compose the exoskeleton, this article presents a preliminary assessment of the device; several tests to characterize its nominal operation have been carried out, as well as position and force control tests to study its controllability and evaluate its suitability as a force assistive device.


Assuntos
Atividade Extraespaçonave/fisiologia , Mãos/fisiologia , Sistema Musculoesquelético/fisiopatologia , Robótica/instrumentação , Voo Espacial/instrumentação , Astronautas , Luvas Protetoras , Força da Mão/fisiologia , Humanos , Fenômenos Mecânicos , Tecnologia Assistiva , Trajes Espaciais
14.
Aerosp Med Hum Perform ; 89(11): 985-995, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30352651

RESUMO

INTRODUCTION: Human-spacesuit fit is not well understood, especially in relation to operational performance and injury risk. Current fit decisions use subjective feedback. This work developed and evaluated new metrics for quantifying fit and assessed metric sensitivity to changes in padding between the human and hip brief assembly (HBA).METHODS: Three subjects donned the Mark III (MKIII) spacesuit with three padding thicknesses between the lower body and HBA. Subjects performed a walking task with inertial measurement units on the thigh and shin of both the human and suit. For each step, cadence, human knee task range of motion (tRoM), difference in human and suit tROM (ΔtRoM), and the relative coordination metric (ρ) between the human-suit femur and tibia were computed.RESULTS: The MKIII significantly reduced user cadence by 20.4% and reduced tRoM by 16.5% during walking with subject-dependent changes due to added padding. In general, the addition of padding significantly altered ΔtRoM; however, variability did exist between subjects. Mixed-effect regressions of dynamic fit (ρ) reflect distinct positive spikes in ρ around heel strike (human-dominated motion) and negative dips following toe off (suit-dominated motion).DISCUSSION: There were mixed effects of padding on gait performance and dynamic fit measures. Differences in dynamic fit between subjects may be more reliant on alternate aspects of fit, such as suit component sizes and designs, than padding level. Subjective feedback supported quantitative observations, highlighting metric utility. Future work will explore the effects of suit sizing components on measures of fit and performance.Fineman RA, McGrath TM, Kelty-Stephen DG, Abercromby AFJ, Stirling LA. Objective metrics quantifying fit and performance in spacesuit assemblies. Aerosp Med Hum Perform. 2018; 89(11):985-995.


Assuntos
Amplitude de Movimento Articular , Trajes Espaciais , Caminhada , Adulto , Desenho de Equipamento , Humanos , Masculino , Análise e Desempenho de Tarefas
15.
Undersea Hyperb Med ; 45(4): 427-436, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30241122

RESUMO

Astronauts training for extravehicular activity (EVA) operations can spend many hours submerged underwater in a pressurized suit, called an extravehicular mobility unit (EMU), exposed to pressures exceeding 2 atmospheres absolute (ATA). To minimize the risk of decompression sickness (DCS) a 46% nitrox mixture is used. This limits the nitrogen partial pressure, decreasing the risk of DCS. The trade-off with using a 46% nitrox mixture is the increased potential for oxygen toxicity, which can lead to severe neurologic symptoms including seizures. Suited runs, which typically expose astronauts of 0.9-1.1 ATA for longer than six hours, routinely exceed the recommendation for central nervous system oxygen toxicity limits (CNSOTL) published by the National Oceanic and Atmospheric Administration (NOAA). Fortunately, in over 50,000 hours of suited training dives spanning 20 years of EVA training operations at NASA's Neutral Buoyancy Laboratory (NBL) there has never been an occurrence of oxygen toxicity. This lends support to anecdotal sentiment among certain members of the hyperbaric community that the NOAA CNSOTL recommendations might be overly conservative, at least for the oxygen pressure and time regime in which NBL operates. The NOAA CNSOTL recommendations are the result of expert consensus with a focus on safety and do not necessarily reflect rigorous experimental evidence. The data from the NBL suited dive operations provide a foundation of evidence that can help inform the expert discussion on dive-related neurologic oxygen toxicity performance and overnight recovery in young, healthy males.


Assuntos
Doenças do Sistema Nervoso Central/prevenção & controle , Imersão , Doenças Profissionais/prevenção & controle , Exposição Ocupacional/normas , Oxigênio/envenenamento , Trajes Espaciais , United States National Aeronautics and Space Administration , Adulto , Pressão Atmosférica , Doenças do Sistema Nervoso Central/etiologia , Doença da Descompressão/prevenção & controle , Mergulho/fisiologia , Feminino , Guias como Assunto/normas , Humanos , Masculino , Exame Neurológico , Nitrogênio/administração & dosagem , Oxigênio/administração & dosagem , Pressão Parcial , Padrões de Referência , Treinamento por Simulação/métodos , Voo Espacial , Fatores de Tempo , Estados Unidos , United States Government Agencies/normas , Simulação de Ausência de Peso/métodos
16.
Life Sci Space Res (Amst) ; 18: 1-11, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30100142

RESUMO

As manned spaceflights beyond low Earth orbit are in the agenda of Space Agencies, the concerns related to space radiation exposure of the crew are still without conclusive solutions. The risk of long-term detrimental health effects needs to be kept below acceptable limits, and emergency countermeasures must be planned to avoid the short-term consequences of exposure to high particle fluxes during hardly predictable solar events. Space habitat shielding cannot be the ultimate solution: the increasing complexity of future missions will require astronauts to protect themselves in low-shielded areas, e.g. during emergency operations. Personal radiation shielding is promising, particularly if using available resources for multi-functional shielding devices. In this work we report on all steps from the conception, design, manufacturing, to the final test on board the International Space Station (ISS) of the first prototype of a water-filled garment for emergency radiation shielding against solar particle events. The garment has a good shielding potential and comfort level. On-board water is used for filling and then recycled without waste. The successful outcome of this experiment represents an important breakthrough in space radiation shielding, opening to the development of similarly conceived devices and their use in interplanetary missions as the one to Mars.


Assuntos
Astronautas , Radiação Cósmica/efeitos adversos , Proteção Radiológica/instrumentação , Trajes Espaciais/normas , Vestuário , Humanos , Modelos Teóricos , Imagens de Fantasmas , Doses de Radiação , Lesões por Radiação/etiologia , Lesões por Radiação/prevenção & controle , Voo Espacial
17.
J Arthroplasty ; 33(5): 1524-1529, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29317156

RESUMO

BACKGROUND: The role of space suits in the prevention of orthopedic prosthetic joint infection remains unclear. Recent evidence suggests that space suits may in fact contribute to increased infection rates, with bioaerosol emissions from space suits identified as a potential cause. This study aimed to compare the particle and microbiological emission rates (PER and MER) of space suits and standard surgical clothing. METHODS: A comparison of emission rates between space suits and standard surgical clothing was performed in a simulated surgical environment during 5 separate experiments. Particle counts were analyzed with 2 separate particle counters capable of detecting particles between 0.1 and 20 µm. An Andersen impactor was used to sample bacteria, with culture counts performed at 24 and 48 hours. RESULTS: Four experiments consistently showed statistically significant increases in both PER and MER when space suits are used compared with standard surgical clothing. One experiment showed inconsistent results, with a trend toward increases in both PER and MER when space suits are used compared with standard surgical clothing. CONCLUSION: Space suits cause increased PER and MER compared with standard surgical clothing. This finding provides mechanistic evidence to support the increased prosthetic joint infection rates observed in clinical studies.


Assuntos
Artroplastia de Substituição/instrumentação , Infecção Hospitalar/microbiologia , Complicações Intraoperatórias/microbiologia , Salas Cirúrgicas , Infecções Relacionadas à Prótese/prevenção & controle , Roupa de Proteção , Infecção da Ferida Cirúrgica/microbiologia , Movimentos do Ar , Poluentes Atmosféricos/efeitos adversos , Artroplastia de Substituição/efeitos adversos , Desenho de Equipamento , Humanos , Transmissão de Doença Infecciosa do Profissional para o Paciente/prevenção & controle , Ortopedia/métodos , Material Particulado/efeitos adversos , Trajes Espaciais
18.
Aerosp Med Hum Perform ; 89(1): 58-62, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29233245

RESUMO

BACKGROUND: Future space missions beyond low Earth orbit will require deconditioned astronauts to perform occupationally relevant tasks within a planetary spacesuit. The prediction of time-to-completion (TTC) of astronaut tasks will be critical for crew safety, autonomous operations, and mission success. This exploratory study determined if the addition of task-specific strength testing to current standard lower body testing would enhance the prediction of TTC in a 1-G test battery. METHODS: Eight healthy participants completed NASA lower body strength tests, occupationally specific strength tests, and performed six task simulations (hand drilling, construction wrenching, incline walking, collecting weighted samples, and dragging an unresponsive crewmember to safety) in a 48-kg weighted suit. The TTC for each task was recorded and summed to obtain a total TTC for the test battery. Linear regression was used to predict total TTC with two models: 1) NASA lower body strength tests; and 2) NASA lower body strength tests + occupationally specific strength tests. RESULTS: Total TTC of the test battery ranged from 20.2-44.5 min. The lower body strength test alone accounted for 61% of the variability in total TTC. The addition of hand drilling and wrenching strength tests accounted for 99% of the variability in total TTC. DISCUSSION: Adding occupationally specific strength tests (hand drilling and wrenching) to standard lower body strength tests successfully predicted total TTC in a performance test battery within a weighted suit. Future research should couple these strength tests with higher fidelity task simulations to determine the utility and efficacy of task performance prediction.Taylor A, Kotarsky CJ, Bond CW, Hackney KJ. Occupational-specific strength predicts astronaut-related task performance in a weighted suit. Aerosp Med Hum Perform. 2018; 89(1):58-62.


Assuntos
Astronautas/estatística & dados numéricos , Trajes Espaciais , Análise e Desempenho de Tarefas , Adulto , Peso Corporal , Feminino , Humanos , Masculino , Voo Espacial
19.
Life Sci Space Res (Amst) ; 15: 69-78, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29198316

RESUMO

We present a design study for a wearable radiation-shielding spacesuit, designed to protect astronauts' most radiosensitive organs. The suit could be used in an emergency, to perform necessary interventions outside a radiation shelter in the space habitat in case of a Solar Proton Event (SPE). A wearable shielding system of the kind we propose has the potential to prevent the onset of acute radiation effects in this scenario. In this work, selection of materials for the spacesuit elements is performed based on the results of dedicated GRAS/Geant4 1-dimensional Monte Carlo simulations, and after a trade-off analysis between shielding performance and availability of resources in the space habitat. Water is the first choice material, but also organic compounds compatible with a human space habitat are considered (such as fatty acids, gels and liquid organic wastes). Different designs and material combinations are proposed for the spacesuits. To quantify shielding performance we use GRAS/Geant4 simulations of an anthropomorphic phantom in an average SPE environment, with and without the spacesuit, and we compare results for the dose to Blood Forming Organs (BFO) in Gy-Eq, i.e. physical absorbed dose multiplied by the proton Relative Biological Effectiveness (RBE) for non-cancer effects. In case of SPE occurrence for Intra-Vehicular Activities (IVA) outside a radiation shelter, dose reductions to BFO in the range of 44-57% are demonstrated to be achievable with the spacesuit designs made only of water elements, or of multi-layer protection elements (with a thin layer of a high density material covering the water filled volume). Suit elements have a thickness in the range 2-6 cm and the total mass for the garment sums up to 35-43 kg depending on model and material combination. Dose reduction is converted into time gain, i.e. the increase of time interval between the occurrence of a SPE and the moment the dose limit to the BFO for acute effects is reached. Wearing a radiation shielding spacesuit of the kind we propose, the astronaut could have up to more than the double the time (e.g. almost 6 instead of 2.5 h) to perform necessary interventions outside a radiation shelter during a SPE, his/her exposure remaining within dose limits. An indicative mass saving thanks to the shielding provided by the suits is also derived, calculating the amount of mass needed in addition to the 1.5 cm thick Al module considered for the IVA scenario to provide the same additional shielding given by the spacesuit. For an average 50% dose reduction to BFO this is equal to about 2.5 tons of Al. Overall, our results offer a proof-of-principle validation of a complementary personal shielding strategy in emergency situations in case of a SPE event. Such results pave the way for the design and realization of a prototype of a water-filled garment to be tested on board the International Space Station for wearability. A successful outcome will possibly lead to the further refining of the design of radiation protection spacesuits and their possible adoption in future long-duration manned missions in deep space.


Assuntos
Astronautas , Radiação Cósmica/efeitos adversos , Imagens de Fantasmas , Lesões por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Trajes Espaciais/normas , Simulação por Computador , Relação Dose-Resposta à Radiação , Humanos , Modelos Teóricos , Doses de Radiação , Lesões por Radiação/etiologia , Eficiência Biológica Relativa
20.
Aerosp Med Hum Perform ; 88(6): 589-596, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28539149

RESUMO

INTRODUCTION: The Mark III (MIII) space suit assembly (SSAs) implements a multibearing, hard-material hip brief assembly (HBA). We hypothesize that: 1) the MIII HBA restricts operator mobility and agility which manifests in effects to gait parameters; 2) the waist bearing provides rotational motion, partially alleviating the restrictions; and 3) there are resistive, speed-dependent torques associated with the spinning bearings which further diminish mobility and agility. METHODS: A subject (Suited and Unsuited) performed two planetary tasks-walking forward (WF) and backward (WB). An analysis of variance (ANOVA) and post hoc comparisons were performed to determine interaction effects. Motion capture data was processed to obtain gait parameters: static base (m), dynamic base (m), step length (m), stride length (m), cadence (steps/min), center of mass speed (m · s-1), foot clearance (toe and heel) (m), and bearing angular velocities (° · s-1). RESULTS: The static base when Suited (0.355 m) was larger than Unsuited (0.263 m). The Suited dynamic base (pooled, 0.200 m) was larger than both Unsuited WF (0.081 m) and WB (0.107 m). When Suited, the operator had lower clearance heights. The waist bearings provided about 7.2° of rotation when WB and WF. The maximum torque, while WF, in the right upper and mid bearings was 15.6 ± 1.35 Nm and 16.3 ± 1.28 Nm. DISCUSSION: This study integrated suit component properties and the emergent biomechanics of the operator to investigate how biomechanics are affected. The human hip has three collocated degrees of freedom (DOFs), whereas the HBA has a single DOF per bearing. The results can inform requirements for future SSA and other wearable system designs and evaluations.Cullinane CR, Rhodes RA, Stirling LA. Mobility and agility during locomotion in the Mark III space suit. Aerosp Med Hum Perform. 2017; 88(6):589-596.


Assuntos
Marcha , Locomoção , Trajes Espaciais , Adulto , Fenômenos Biomecânicos , Humanos , Masculino
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