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1.
PLoS Pathog ; 16(1): e1008153, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999804

RESUMO

Human space travel is on the verge of visiting Mars and, in the future, even more distant places in the solar system. These journeys will be also made by terrestrial microorganisms (hitchhiking on the bodies of astronauts or on scientific instruments) that, upon arrival, will come into contact with new planetary environments, despite the best measures to prevent contamination. These microorganisms could potentially adapt and grow in the new environments and subsequently recolonize and infect astronauts. An even more challenging situation would be if truly alien microorganisms will be present on these solar system bodies: What will be their pathogenic potential, and how would our immune host defenses react? It will be crucial to anticipate these situations and investigate how the immune system of humans might cope with modified terrestrial or alien microbes. We propose several scenarios that may be encountered and how to respond to these challenges.


Assuntos
Equipamentos e Provisões/microbiologia , Interações Hospedeiro-Patógeno , Sistema Imunitário/imunologia , Astronautas , Exobiologia , Meio Ambiente Extraterreno , Humanos , Voo Espacial , Astronave
2.
PLoS One ; 15(1): e0226434, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31967993

RESUMO

A round-trip human mission to Mars is anticipated to last roughly three years. Spaceflight conditions are known to cause loss of bone mineral density (BMD) in astronauts, increasing bone fracture risk. There is an urgent need to understand BMD progression as a function of spaceflight time to minimize associated health implications and ensure mission success. Here we introduce a nonlinear mathematical model of BMD loss for candidate human missions to Mars: (i) Opposition class trajectory (400-600 days), and (ii) Conjunction class trajectory (1000-1200 days). Using femoral neck BMD data (N = 69) from astronauts after 132-day and 228-day spaceflight and the World Health Organization's fracture risk recommendation, we predicted post-mission risk and associated osteopathology. Our model predicts 62% opposition class astronauts and 100% conjunction class astronauts will develop osteopenia, with 33% being at risk for osteoporosis. This model can help in implementing countermeasure strategies and inform space agencies' choice of crew candidates.


Assuntos
Astronautas/estatística & dados numéricos , Densidade Óssea , Marte , Osteoporose/etiologia , Voo Espacial , Ausência de Peso/efeitos adversos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/diagnóstico
3.
J Surg Res ; 246: 305-314, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31731248

RESUMO

BACKGROUND: Long-duration exploration missions (LDEMs), such as voyages to Mars, will present unique medical challenges for astronaut crews, including communication delays and the inability to return to Earth early. Medical events threaten crewmember lives and increase the risk of mission failure. Managing a range of potential medical events will require excellent technical and nontechnical skills (NTSs). We sought to identify medical events with potential for rescue, range them according to the potential impact on crew health and mission success during LDEMs, and develop a list of NTSs to train for management of in-flight medical events. MATERIALS AND METHODS: Twenty-eight subject matter experts with specializations in surgery, medicine, trauma, spaceflight operations, NTS training, simulation, human factors, and organizational psychology completed online surveys followed by a 2-d in-person workshop. They identified and rated medical events for survivability, mission impact, and impact of crewmember NTSs on outcomes in space. RESULTS: Sudden cardiac arrest, smoke inhalation, toxic exposure, seizure, and penetrating eye injury emerged as events with the highest potential mission impact, greatest potential for survival, and that required excellent NTS for successful management. Key NTS identified to target in training included information exchange, supporting behavior, communication delivery, and team leadership/followership. CONCLUSIONS: With a planned Mars mission on the horizon, training countermeasures need to be developed in the next 3-5 y. These results may inform policy, selection, medical system design, and training scenarios for astronauts to manage in-flight medical events on LDEMs. Findings may extend to surgical and medical care in any rural and remote location.


Assuntos
Astronautas/educação , Marte , Voo Espacial/métodos , Sobrevivência , Astronautas/psicologia , Consenso , Morte Súbita Cardíaca , Ferimentos Oculares Penetrantes/terapia , Humanos , Liderança , Convulsões/terapia , Lesão por Inalação de Fumaça/terapia , Fatores de Tempo
5.
Science ; 366(6465): 581, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31672886
6.
Pharm Res ; 36(10): 148, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31414302

RESUMO

Medications have been used during space missions for more than half a century, yet our understanding of the effects of spaceflight on drug pharmacokinetics and pharmacodynamics is poor. The space environment induces time-dependent alterations in human physiology that include fluid shifts, cardiovascular deconditioning, bone and muscle density loss, and impaired immunity. This review presents the current knowledge on the physiological effects of spaceflight that can translate into altered drug disposition and activity and eventually to inadequate treatment. It describes findings from studies in astronauts along with mechanistic studies in animal models and in vitro systems. Future missions into deeper space and the emergence of commercial spaceflight will require a more detailed understanding of space pharmacology to optimize treatment in astronauts and space travelers.


Assuntos
Preparações Farmacêuticas/administração & dosagem , Preparações Farmacêuticas/metabolismo , Medicina Aeroespacial , Animais , Astronautas , Gravitação , Humanos , Farmacocinética , Voo Espacial , Ausência de Peso/efeitos adversos
7.
Life Sci Space Res (Amst) ; 22: 76-88, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31421851

RESUMO

Galactic cosmic rays (GCR) are a constant source of radiation that constitutes one of the major hazards during deep space exploration missions for both astronauts and hardware. In this work, GCR models commonly used by the space radiation protection community are compared with recently published high-precision, high-resolution measurements of cosmic ray lithium, beryllium, boron, carbon, nitrogen, and oxygen fluxes along with their ratios (Li/B, Li/C, Li/O, Be/B, Be/C, Be/O, B/C, B/O, C/O, N/B, N/O) from the Alpha Magnetic Spectrometer (AMS). All of the models were developed and calibrated prior to the publication of this AMS data, therefore this is an opportunity to validate the models against an independent data set. This paper is a compliment to the previously published comparison of GCR models with AMS hydrogen, helium, and the boron-to-carbon ratio (Norbury et al., 2018).


Assuntos
Radiação Cósmica , Meio Ambiente Extraterreno , Modelos Teóricos , Astronautas , Humanos , Voo Espacial , Análise Espectral
8.
Life Sci Space Res (Amst) ; 22: 98-124, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31421854

RESUMO

The space radiation environment is a complex mixture of particle types and energies originating from sources inside and outside of the galaxy. These environments may be modified by the heliospheric and geomagnetic conditions as well as planetary bodies and vehicle or habitat mass shielding. In low Earth orbit (LEO), the geomagnetic field deflects a portion of the galactic cosmic rays (GCR) and all but the most intense solar particle events (SPE). There are also dynamic belts of trapped electrons and protons with low to medium energy and intense particle count rates. In deep space, the GCR exposure is more severe than in LEO and varies inversely with solar activity. Unpredictable solar storms also present an acute risk to astronauts if adequate shielding is not provided. Near planetary surfaces such as the Earth, moon or Mars, secondary particles are produced when the ambient deep space radiation environment interacts with these surfaces and/or atmospheres. These secondary particles further complicate the local radiation environment and modify the associated health risks. Characterizing the radiation fields in this vast array of scenarios and environments is a challenging task and is currently accomplished with a combination of computational models and dosimetry. The computational tools include models for the ambient space radiation environment, mass shielding geometry, and atomic and nuclear interaction parameters. These models are then coupled to a radiation transport code to describe the radiation field at the location of interest within a vehicle or habitat. Many new advances in these models have been made in the last decade, and the present review article focuses on the progress and contributions made by workers and collaborators at NASA Langley Research Center in the same time frame. Although great progress has been made, and models continue to improve, significant gaps remain and are discussed in the context of planned future missions. Of particular interest is the juxtaposition of various review committee findings regarding the accuracy and gaps of combined space radiation environment, physics, and transport models with the progress achieved over the past decade. While current models are now fully capable of characterizing radiation environments in the broad range of forecasted mission scenarios, it should be remembered that uncertainties still remain and need to be addressed.


Assuntos
Radiação Cósmica , Modelos Teóricos , Astronautas , Humanos , Física Nuclear , Atividade Solar , Voo Espacial , Astronave , Estados Unidos , United States National Aeronautics and Space Administration
9.
Aerosp Med Hum Perform ; 90(9): 782-787, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426893

RESUMO

INTRODUCTION: Critical mission tasks for Martian exploration have been identified and include specific duties that astronauts will have to perform despite any adverse effects of chronic microgravity. Specifically, astronauts may have to perform an emergency capsule egress upon return to Earth, which places specific demands on compromised cardiovascular and neuromuscular systems. Therefore, the purpose of this project was to determine the relationship between cardiorespiratory fitness and simulated capsule egress time.METHODS: There were 15 subjects who volunteered for this study. Vo2peak and peak power output (PPO) were determined on cycle and rowing ergometers. Critical power (CP) was determined by a 3-min all-out rowing test. Subjects then performed an emergency capsule egress on a mock-up of NASA's Orion space capsule. Peak metabolic data were compared between the cycling and rowing tests. Pearson's correlation was used to identify relationships between egress time and Vo2peak, PPO, and CP.RESULTS: Vo2peak, Vco2peak, and minute ventilation were not different between cycling and rowing tests. Cycling elicited a greater PPO than the rowing test. Egress time was negatively correlated to rowing PPO (r = -0.60), but not cycling or rowing Vo2peak, cycling PPO, or CP.CONCLUSIONS: Rowing PPO/kg correlates with egress time. Although individuals with higher PPO/kg were able to finish the task in less time, individuals with low fitness levels (Vo2peak ≤ 20 ml · kg-1 · min-1) could complete the egress within 2 mins. These results suggest that cardiorespiratory fitness should not limit emergency egress and that this can be assessed using rowing exercise.Alexander AM, Sutterfield SL, Kriss KN, Hammer SM, Didier KD, Cauldwell JT, Dzewaltowski AC, Barstow TJ, Ade CJ. Prediction of emergency capsule egress performance. Aerosp Med Hum Perform. 2019; 90(9):782-787.


Assuntos
Astronautas , Aptidão Cardiorrespiratória/fisiologia , Emergências , Voo Espacial/instrumentação , Adulto , Teste de Esforço , Feminino , Humanos , Masculino , Marte , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Fatores de Tempo
10.
Aerosp Med Hum Perform ; 90(9): 807-812, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426897

RESUMO

INTRODUCTION: The previous Spacecraft Maximal Allowable Concentrations (SMACs) for methanol were established by characterizing minor effects upon cognitive functions as a no-observable adverse effects level (NOAEL). However, an increasing awareness of the risk posed by Space-Associated Neuro-ocular Syndrome (SANS) has caused NASA Toxicology to reexamine SMACs for methanol because exposure to it can also adversely affect ocular health. An updated review of the literature indicates that no adjustments to the SMACs due to SANS complications were required, while confirming that effects upon the central nervous system remain the appropriate basis for the SMACs for methanol. Our review, however, identified several issues that provide justification for modest SMAC reductions. It has recently been recognized that inhaled methanol may reach the brain via the olfactory system and be absorbed there into the highly toxic metabolite formaldehyde. A benchmark dose (BMD) for an extra risk of 10%, derived from an analysis of the incidences of neurological lesions in monkeys chronically exposed to methanol, is an order of magnitude less than the Environmental Protection Agency's (EPA's) reference concentration for chronic inhalation of methanol. Reports calling attention to the relative insensitivity of traditional methods of assessing cognitive function erode confidence that adverse effects at the concentration reported as a NOAEL would have been recognizable. Therefore, an additional modest safety factor of three is applied to SMACs for methanol.Scully RR, Garcia H, McCoy JT, Ryder VE. Revisions to limits for methanol in the air of spacecraft. Aerosp Med Hum Perform. 2019; 90(9):807-812.


Assuntos
Cognição/efeitos dos fármacos , Metanol/toxicidade , Síndromes Neurotóxicas/prevenção & controle , Astronave/normas , Níveis Máximos Permitidos , Animais , Astronautas , Modelos Animais de Doenças , Haplorrinos , Humanos , Incidência , Concentração Máxima Permitida , Síndromes Neurotóxicas/epidemiologia , Síndromes Neurotóxicas/etiologia , Nível de Efeito Adverso não Observado , Exposição Ocupacional/normas , Testes de Toxicidade Crônica
11.
Aerosp Med Hum Perform ; 90(9): 819-825, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426899

RESUMO

INTRODUCTION: Spaceflight can strain astronaut physical, physiological, and mental well-being, whereas maintaining astronaut operational performance remains an essential goal. Although various cognitive tests have been used for spaceflight assessment, these have been challenged on their lack of operational relevance.METHODS: To address this gap, we developed and characterized the Robotic On-Board Trainer for Research (ROBoT-r) system, based on the Robotic On-Board Trainer (ROBoT) currently used for astronaut training on Canadarm2 track-and-capture activities. The task requires use of dual hand-controllers (6 degrees of freedom) to grapple an incoming vehicle in free-drift in a time-limited setting. After developing a platform for conducting research studies, characterization testing of ROBoT-r was completed by 14 astronaut-like volunteers (35 ± 11 yr; N = 5 women) over 16 sessions each.RESULTS: We describe the design and capabilities of the ROBoT-r system for conducting operationally relevant research on human performance. Version 6.2 of the system supports H-II Transfer Vehicle track-and-capture operations within a multimillion component, physics-enabled 3D model using NASA's DOUG graphics platform. It has configurable task initialization and auto-run capabilities, saves 38 variables continuously at 20 Hz throughout each run, provides the user quantitative feedback after each run, and provides summaries after each session. Detailed performance characterization data is reported for future experimental planning purposes.DISCUSSION: ROBoT-r's range of performance variables enables detailed and quantitative performance assessment. Its use in spaceflight will help provide insight into operational performance, as well as allowing investigators to compare these results with more traditional cognitive tests to help better understand the interaction between individual cognitive abilities and operational performance.Ivkovic V, Sommers B, Cefaratti DA, Newman G, Thomas DW, Alexander DG, Strangman GE. Operationally relevant behavior assessment using the Robotic On-Board Trainer for Research (ROBoT-r). Aerosp Med Hum Perform. 2019; 90(9):819-825.


Assuntos
Astronautas/psicologia , Técnicas de Observação do Comportamento/instrumentação , Treinamento com Simulação de Alta Fidelidade/métodos , Voo Espacial , Análise e Desempenho de Tarefas , Adulto , Técnicas de Observação do Comportamento/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Competência Profissional , Robótica , Adulto Jovem
16.
Soins ; 64(836): 18-23, 2019 Jun.
Artigo em Francês | MEDLINE | ID: mdl-31208576

RESUMO

Today, sending people into space has become almost routine. However, it is a potentially dangerous environment for humans. Astronauts' health is closely monitored to ensure they are fit to continue their mission. The conquest of space has also resulted in the development of numerous tools and medicines beneficial for all living beings on Earth.


Assuntos
Astronautas , Assistência à Saúde/organização & administração , Difusão de Inovações , Voo Espacial , Humanos
17.
Lancet Psychiatry ; 6(7): 570-572, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31230682
18.
Aerosp Med Hum Perform ; 90(7): 624-631, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31227036

RESUMO

BACKGROUND: Voice analysis offers an unobtrusive approach for psychological monitoring. We demonstrate the relationship between voice parameters and cognitive performance in: 1) a task with psychological test character, and 2) performance in an operational, mission-relevant task. The central methodological aim was to verify the usefulness of voice commands and counting in providing anchor values for the step-function model of voice pitch.METHODS: During a 22-yr period, 42 cosmonauts participated in the Russian space experiment "Pilot", which was a hand-controlled docking maneuver. As reference the experiment included the cognitive task "Manometer." This task was controlled through voice commands. These voice commands were stored and are the basis for the present analysis.RESULTS: Cosmonauts differed in their working style and respective performance during the Manometer task. Clustered groups can be assumed to represent different effort. Importantly, these groups differed in the changes of voice pitch among mission phases and among task repetitions. However, there were no differences between these motivation groups and performance in the professional task.DISCUSSION: The differing effort is the effect of different motivation of cosmonauts for experimental test tasks vs. mission-relevant professional tasks. Latter ones provide a more reliable chance to assess the real actual state and skills of a cosmonaut. Voice pitch measurement seems to be reliable and useful under space conditions for monitoring this volitional effort.Johannes B, Bronnikov SV, Bubeev JA, Kotrovskaya TI, Shastlivtseva DV, Piechowski S, Hoermann H-J, Rittweger J, Jordan J. Operational and experimental tasks, performance, and voice in space. Aerosp Med Hum Perform. 2019; 90(7):624-631.


Assuntos
Astronautas/psicologia , Voo Espacial , Acústica da Fala , Voz/fisiologia , Adulto , Cognição/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Federação Russa , Volição/fisiologia
19.
Aerosp Med Hum Perform ; 90(7): 647-651, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31227040

RESUMO

INTRODUCTION: Research on the mortality of space explorers has focused exclusively on U.S. astronauts and Soviet and Russian cosmonauts. However, other nations have organized space programs over the last 40 yr and the European Space Agency, the Canadian Space Agency, the China National Space Administration, and the Japan Aerospace Exploration Agency all offer an opportunity for further study of the mortality of space explorers.METHODS: We used biographical and vital data abstracted from public sources for European, Canadian, Chinese, and Japanese astronauts. Using general population mortality rates from the Human Mortality Database and mortality rates derived from the cohort of U.S. astronauts, we computed standardized mortality ratios.RESULTS: The groups displayed different preferences in selection of astronauts. As there were no deaths in any of the four groups, the point estimates for standardized mortality ratios were all 0. However, the European cohort experienced a statistically significant reduction in all-cause mortality risk in comparison to the European general population as well as in comparison to U.S. astronauts.DISCUSSION: The healthy worker effect predicts that all study cohorts should have lower all-cause mortality risk in comparison to their general populations. The general population of Japan has mortality rates low enough that any reduction in mortality risk may remain undetectable in the Japanese cohort. Continued surveillance of these populations in the coming decades will make them a useful addition to the evidence base for astronaut mortality.Reynolds RJ, Day SM. Mortality among international astronauts. Aerosp Med Hum Perform. 2019; 90(7):647-651.


Assuntos
Astronautas/estatística & dados numéricos , Mortalidade/tendências , Adulto , Canadá/epidemiologia , China/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Seguimentos , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Estados Unidos/epidemiologia
20.
Med Hypotheses ; 127: 63-65, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31088650

RESUMO

Dream periods during sleep have been observed in most mammals as early in history as antiquity. Sleep researchers at the University of Chicago, discovered the phase of rapid eye movement (REM) during sleep and connected it to the dream period. During this period, called the REM phase (after the American terminology), although the brain shows electrical activity, it is insensitive to external stimulations, including light, sound, contact and, a little unexpectedly, gravity. However, since this discovery was mаde there has been no definitive explanation of the rapid eye movements Many possible explanations have been offered, and yet, the causes and contributing factors of the REM sleep phase are inadequately understood. It has often been proposed that the eyes observe the images produced during dreams, but researchers are not convinced. It is proposed here that the movements of the eyes during REM sleep are due to a feeling of disorientation and a subjective loss of landmarks. During the REM sleep phase, the brain has a reduced sensation of gravity, and the sleeper is in a state similar to weightlessness. The instinctive search for the vertical or horizontal direction triggers movements of the eyes, looking for usual points of reference. This hypothesis is reinforced by an original experiment that was conducted in space. The frequency of the eye movements of astronauts during their first night in space is 10 times more than what is experienced on the ground, and that moment in time is when the feeling or the sensation of weightlessness is certainly the most disturbing. Upon the return to Earth, the frequency of the eye movements increases again the first night after landing. These two moments are when the effects of gravity are felt most drastically. The present assumption needs to be validated experimentally and may necessitate further research.


Assuntos
Encéfalo/fisiologia , Gravitação , Sono REM , Sono/fisiologia , Ausência de Peso , Astronautas , Sonhos , Humanos , Modelos Biológicos , Voo Espacial
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