Sleep-Monitoring Technology Progress and Its Application in Space.

INTRODUCTION: Sleep is an indispensable physiological phenomenon. The complexity of sleep and the time it occupies in human life determine that its quality is positively correlated with human health. Since polysomnography was used in spaceflight in 1967, the sleep problem during astronaut flight has been studied in depth for more than 50 yr, and many solutions have been proposed, but astronauts have always had sleep problems during orbital flight. Insufficient sleep and changes in the rhythm of human sleep-wake activity will lead to disturbance of the human body's internal rhythm indicators, which will lead to psychological and emotional fluctuations and reduced cognitive ability, decision-making ability, teamwork, and work performance. NASA has identified operational errors due to sleep deprivation and altered circadian rhythms as an important risk factor in the key biomedical roadmap for long-term flight, so the importance of sleep monitoring in spaceflight is self-evident. On-orbit sleep-monitoring methods include both subjective and objective aspects. We review objective sleep-monitoring technology based on its application, main monitoring physiological indicators, intrusive advantages, and limitations. This paper reviews the subjective and objective sleep evaluation methods for on-orbit applications, summarizes the progress, advantages, and disadvantages of current ground sleep-monitoring technologies and equipment, and looks forward to the application prospects of new sleep-monitoring technologies in spaceflight.Zhang C, Chen Y, Fan Z, Xin B, Wu B, Lv K. Sleep-monitoring technology progress and its application in space. Aerosp Med Hum Perform. 2024; 95(1):37-44.

Cognition in zero gravity: Effects of non-terrestrial gravity on human behaviour.

As humanity prepares for deep space exploration, understanding the impact of spaceflight on bodily physiology is critical. While the effects of non-terrestrial gravity on the body are well established, little is known about its impact on human behaviour and cognition. Astronauts often describe dramatic alterations in sensorimotor functioning, including orientation, postural control, and balance. Changes in cognitive functioning as well as in socio-affective processing have also been observed. Strikingly, no comprehensive theoretical model exists to outline the impact of non-terrestrial gravity on behaviour. Here, we have reviewed the key literature across the last 10 years and explored the impact of non-terrestrial gravity across three key functional domains: sensorimotor functioning, cognition, and socio-affective processing. We have proposed and preliminary validated a neurocognitive model to account for the effects of non-terrestrial gravity in these domains. Understanding the impact of non-terrestrial gravity on human behaviour has never been timelier and it will help mitigate against risks in both commercial and non-commercial spaceflight.

Crew Autonomy During Simulated Medical Event Management on Long Duration Space Exploration Missions.

OBJECTIVE: Our primary aim was to investigate crew performance during medical emergencies with and without ground-support from a flight surgeon located at mission control. BACKGROUND: There are gaps in knowledge regarding the potential for unanticipated in-flight medical events to affect crew health and capacity, and potentially compromise mission success. Additionally, ground support may be impaired or periodically absent during long duration missions. METHOD: We reviewed video recordings of 16 three-person flight crews each managing four unique medical events in a fully immersive spacecraft simulator. Crews were randomized to two conditions: with and without telemedical flight surgeon (FS) support. We assessed differences in technical performance, behavioral skills, and cognitive load between groups. RESULTS: Crews with FS support performed better clinically, were rated higher on technical skills, and completed more clinical tasks from the medical checklists than crews without FS support. Crews with FS support also had better behavioral/non-technical skills (information exchange) and reported significantly lower cognitive demand during the medical event scenarios on the NASA-TLX scale, particularly in mental demand and temporal demand. There was no significant difference between groups in time to treat or in objective measures of cognitive demand derived from heart rate variability and electroencephalography. CONCLUSION: Medical checklists are necessary but not sufficient to support high levels of autonomous crew performance in the absence of real-time flight surgeon support. APPLICATION: Potential applications of this research include developing ground-based and in-flight training countermeasures; informing policy regarding autonomous spaceflight, and design of autonomous clinical decision support systems.

Astronaut Candidate, Candidate-Like, and Undergraduate Subjects Compared on Retention and Transfer.

INTRODUCTION: The present study examined long-term retention and transfer of knowledge and skills, as well as the effect of cognitive load on retention and transfer, using a sample of astronaut candidates and two comparison groups. The first comparison group, recruited from Johnson Space Center, was similar in age, education, and general health to the astronaut candidate group; the second comparison group included university undergraduate students.METHODS:This study employed two different tasks-a simple perceptual-motor task involving data entry and a complex memory updating task requiring both prospective and retrospective memory. Subjects completed multiple sessions involving both tasks over a 500-d period, with test sessions involving transfer and/or a cognitive load manipulation. For the perceptual-motor task, transfer involved changes to the stimuli that increased intrinsic cognitive load or changes to the required motoric procedures. For the memory updating task, extraneous cognitive load was increased by the addition of a concurrent secondary task.RESULTS:For both the perceptual-motor and memory updating tasks, astronaut candidates and candidate-like subjects performed more accurately, with greater speed, and were less impacted by increased cognitive load than undergraduate students. Despite the generally superior performance of astronaut candidates and candidate-like subjects, they were more likely to experience negative transfer on the perceptual-motor task, whereas undergraduate students demonstrated positive transfer.DISCUSSION:Candidate-like subjects provided a more accurate approximation of astronaut candidate performance than did undergraduate students, especially with regard to negative transfer effects and cognitive load.Kole JA, Barshi I, Healy AF, Schneider VI. Astronaut candidate, candidate-like, and undergraduate subjects compared on retention and transfer. Aerosp Med Hum Perform. 2023; 94(12):902-910.

Space missions: psychological and psychopathological issues.

Exploring space is one of the most attractive goals that humanity ever set, notwithstanding, there are some psychological and psychopathological risks that should be considered. Several studies identified some possible hazards of space travels and related physical and psychological consequences on astronauts. If some psychological reactions are obviously inherent to the characteristics of the spaceships (habitability, confinement, psychological, and interpersonal relationships), other (disturbances of sleep-wake cycle, personality changes, depression, anxiety, apathy, psychosomatic symptoms, neurovestibular problems, alterations in cognitive function, and sensory perception) represent a clear warning of possible central nervous system (CNS) alterations, possibly due to microgravity and cosmic radiation. Such conditions and eventual CNS changes might compromise the success of missions and the ability to cope with unexpected events and may lead to individual and long-term impairments. Therefore, further studies are needed, perhaps, requiring the birth of a novel branch of psychology/psychiatry that should not only consider the risks related to space exploration, but the implementation of targeted strategies to prevent them.

Neuro-consequences of the spaceflight environment.

As human space exploration advances to establish a permanent presence beyond the Low Earth Orbit (LEO) with NASA's Artemis mission, researchers are striving to understand and address the health challenges of living and working in the spaceflight environment. Exposure to ionizing radiation, microgravity, isolation and other spaceflight hazards pose significant risks to astronauts. Determining neurobiological and neurobehavioral responses, understanding physiological responses under Central Nervous System (CNS) control, and identifying putative mechanisms to inform countermeasure development are critically important to ensuring brain and behavioral health of crew on long duration missions. Here we provide a detailed and comprehensive review of the effects of spaceflight and of ground-based spaceflight analogs, including simulated weightlessness, social isolation, and ionizing radiation on humans and animals. Further, we discuss dietary and non-dietary countermeasures including artificial gravity and antioxidants, among others. Significant future work is needed to ensure that neural, sensorimotor, cognitive and other physiological functions are maintained during extended deep space missions to avoid potentially catastrophic health and safety outcomes.

Neurokinin-1 Receptor Antagonist Reverses Functional CNS Alteration Caused by Combined γ-rays and Carbon Nuclei Irradiation.

BACKGROUND: Ionizing Radiation (IR) is one of the major limiting factors for human deep-space missions. Preventing IR-induced cognitive alterations in astronauts is a critical success factor. It has been shown that cognitive alterations in rodents can be inferred by alterations of a psycho- emotional balance, primarily an anxiogenic effect of IR. In our recent work, we hypothesized that the neurokinin-1 (NK1) receptor might be instrumental for such alterations. OBJECTIVE: The NK1 receptor antagonist rolapitant and the classic anxiolytic diazepam (as a comparison drug) were selected to test this hypothesis on Wistar rats. METHODS: Pharmacological substances were administered through intragastric probes. We used a battery of tests for a comprehensive ethological analysis. High-performance liquid chromatography was applied to quantify monoamines content. An analysis of mRNA expression was performed by real-time PCR. Protein content was studied by the Western blotting technique. RESULTS: Our salient finding includes no substantial changes in anxiety, locomotor activity and cognitive abilities of treated rats under irradiation. No differences were found in the content of monoamines. We discovered a synchronous effect on mRNA expression and protein content of 5- HT2a and 5-HT4 receptors in the prefrontal cortex, as well as decreased content of serotonin transporter and increased content of tryptophan hydroxylase in the hypothalamus of irradiated rats. Rolapitant affected the protein amount of a number of serotonin receptors in the amygdala of irradiated rats. CONCLUSION: Rolapitant may be the first atypical radioprotector, providing symptomatic treatment of CNS functional disorders in astronauts caused by IR.

Respuesta inmune y vírica en el espacio exterior / Immune and viral response in outer space

Este documento tiene como objetivo principal exponer los riesgos que pueden presentar los astronautas en el sistema inmunitario durante un viaje espacial. Mediante la revisión de la base de datos de la National Aeronautics and Space Administration(NASA), se han elucidado estudios que demuestran que, durante la estancia en la estación espacial, se disminuye la respuesta celular inmune del organismo para responder ante los virus latentes de cada cuerpo humano. Cuando se relaciona este sistema con los vuelos espaciales de larga duración, (1,2,3) se evidencia como la concentración de ciertas citoquinas en el plasma de un astronauta puede ser considerado un indicador de cambios fisiológicos en vivo del sistema inmunológico.(4) Los efectos de la microgravedad en el cuerpo se han transformado en un tema clave de investigación enfocado en el sistema inmunitario. La salud y el bienestar de los viajeros espaciales es estimado como prioridad para las organizaciones encargadas, el Laboratorio de Inmunología del Centro Espacial Johnson de la NASA investiga los efectos del vuelo espacial.(5,6) El Laboratorio de Inmunología del Centro Espacial Johnson tiene datos que sugieren que la supresión del sistema inmunitario que se produce durant e los vuelos espaciales es causada por la radiación y el estrés.(5,6) Se han observado muestras de plasma sanguíneo de las astronautas tomadas antes, durante y después de realizar sus vuelos espaciales. Se reporta que la distribución de células inmunitarias en la sangre se mantiene, cuantitativamente, sin cambios durante misiones cortas, a diferencia de las misiones de periodos prolongados en donde se evidencia una depresión celular y del sistema inmunitario que impide la producción de respuestas adecuadas contra amenazas externas similares a las cuantificadas en el retorno a la tierra(AU)

Immunological Aspects of Isolation and Confinement.

Beyond all doubts, the exploration of outer space is a strategically important and priority sector of the national economy, scientific and technological development of every and particular country, and of all human civilization in general. A number of stress factors, including a prolonged confinement in a limited hermetically sealed space, influence the human body in space on board the spaceship and during the orbital flight. All these factors predominantly negatively affect various functional systems of the organism, in particular, the astronaut's immunity. These ground-based experiments allow to elucidate the effect of confinement in a limited space on both the activation of the immunity and the changes of the immune status in dynamics. Also, due to simulation of one or another emergency situation, such an approach allows the estimation of the influence of an additional psychological stress on the immunity, particularly, in the context of the reserve capacity of the immune system. A sealed chamber seems a convenient site for working out the additional techniques for crew members selection, as well as the countermeasures for negative changes in the astronauts' immune status. In this review we attempted to collect information describing changes in human immunity during isolation experiments with different conditions including short- and long-term experiments in hermetically closed chambers with artificial environment and during Antarctic winter-over.

A review of astronaut mental health in manned missions: Potential interventions for cognitive and mental health challenges.

Space is an isolated, confined environment for humans. These conditions can have numerous effects on astronaut mental health and safety. Psychological and social issues affect space crew due to the isolation, confinement, and prolonged separation from family and friends. This area of research is particularly crucial given the space sector's plans for Martian colonies and space tourism, as well as to aid astronauts when under high stress. Therefore, this paper reviews the effects of isolation/confinement on psychological and cognitive health; impact of radiation and microgravity on cognitive health; and implications of disturbances to the circadian rhythm and sleep in space. Possible solutions to relevant mentioned cognitive and mental health challenges are also discussed.

Factors affecting flavor perception in space: Does the spacecraft environment influence food intake by astronauts?

The intention to send a crewed mission to Mars involves a huge amount of planning to ensure a safe and successful mission. Providing adequate amounts of food for the crew is a major task, but 20 years of feeding astronauts on the International Space Station (ISS) have resulted in a good knowledge base. A crucial observation from the ISS is that astronauts typically consume only 80% of their daily calorie requirements when in space. This is despite daily exercise regimes that keep energy usage at very similar levels to those found on Earth. This calorie deficit seems to have little effect on astronauts who spend up to 12 months on the ISS, but given that a mission to Mars would take 30 to 36 months to complete, there is concern that a calorie deficit over this period may lead to adverse effects in crew members. The key question is why astronauts undereat when they have a supply of food designed to fully deliver their nutritional needs. This review focuses on evidence from astronauts that foods taste different in space, compared to on Earth. The underlying hypothesis is that conditions in space may change the perceived flavor of the food, and this flavor change may, in turn, lead to underconsumption by astronauts. The key areas investigated in this review for their potential impact on food intake are the effects of food shelf life, physiological changes, noise, air and water quality on the perception of food flavor, as well as the link between food flavor and food intake.

Health care for deep space explorers.

[Formula: see text]There is a growing desire amongst space-faring nations to venture beyond the Van Allen radiation belts to a variety of intriguing locations in our inner solar system. Mars is the ultimate destination. In two decades, we hope to vicariously share in the adventure of an intrepid crew of international astronauts on the first voyage to the red planet.This will be a daunting mission with an operational profile unlike anything astronauts have flown before. A flight to Mars will be a 50-million-kilometre journey. Interplanetary distances are so great that voice and data communications between mission control on Earth and a base on Mars will feature latencies up to 20 min. Consequently, the ground support team will not have real-time control of the systems aboard the transit spacecraft nor the surface habitat. As cargo resupply from Earth will be impossible, the onboard inventory of equipment and supplies must be planned strategically in advance. Furthermore, the size, amount, and function of onboard equipment will be constrained by limited volume, mass, and power allowances.With less oversight from the ground, all vehicle systems will need to be reliable and robust. They must function autonomously. Astronauts will rely on their own abilities and onboard resources to deal with urgent situations that will inevitably arise.The deep space environment is hazardous. Zero- and reduced-gravity effects will trigger deconditioning of the cardiovascular, musculoskeletal, and other physiological systems. While living for 2.5 years in extreme isolation, Mars crews will experience psychological stressors such as loss of privacy, reduced comforts of living, and distant relationships with family members and friends.Beyond Earth's protective magnetosphere, the fluence of ionising radiation will be higher. Longer exposure of astronauts to galactic cosmic radiation could result in the formation of cataracts, impaired wound healing, and degenerative tissue diseases. Genetic mutations and the onset of cancer later in life are also possible. Acute radiation sickness and even death could ensue from a large and unpredictable solar particle event.There are many technological barriers that prevent us from carrying out a mission to Mars today. Before launching the first crew, we will need to develop processes for in-situ resource utilisation. Rather than bringing along large quantities of oxygen, water, and propellant from Earth, future astronauts will need to produce some of these consumables from local space-based resources.Ion propulsion systems will be needed to reduce travel times to interplanetary destinations, and we will need systems to land larger payloads (up to 40 tonnes of equipment and supplies for a human mission) on planetary surfaces. These and other innovations will be needed before humans venture into deep space.However, it is the delivery of health care that is regarded as one of the most important obstacles to be overcome. Physicians, biomedical engineers, human factors specialists, and radiation experts are re-thinking operational concepts of health care, crew performance, and life support. Traditional oversight of astronaut health by ground-based medical teams will no longer be possible, particularly in urgent situations. Aborting a deep space mission to medically evacuate an ill or injured crew member to Earth will not be an option. Future crews must have all of the capability and responsibility to monitor and manage their own health. Onboard medical resources must include imaging, surgery, and emergency care, as well as laboratory analysis of blood, urine, and other biospecimens.At least one member of the crew should be a broadly trained physician with experience in remote medicine. She/he will be supported by an onboard health informatics network that is artificial intelligence enabled to assist with monitoring, diagnosis, and treatment. In other words, health care in deep space will become more autonomous, intelligent, and point of care.The International Commission on Radiological Protection (ICRP) has dedicated a day of its 5th International Symposium in Adelaide to the theme of Mars exploration. ICRP has brought global experts together today to consider the pressing issues of radiation protection. There are many issues to be addressed: Can the radiation countermeasures currently used in low Earth orbit be adapted for deep space?Can materials of low atomic weight be integrated into the structure of deep space vehicles to shield the crew?In the event of a major solar particle event, could a safe haven shelter the crew adequately from high doses of radiation?Could Martian regolith be used as shielding material for subterranean habitats?Will shielding alone be sufficient to minimise exposure, or will biological and pharmacological countermeasures also be needed?Beyond this symposium, I will value the continued involvement of ICRP in space exploration. ICRP has recently established Task Group 115 to examine radiation effects on the health of astronaut crew and to recommend exposure limits. This work will be vital. Biological effects of radiation could not only impact the health, well-being, and performance of future explorers, but also the length and quality of their lives.While humanity has dreamed of travel to the red planet for decades, an actual mission is finally starting to feel like a possibility. How exciting! I thank ICRP for its ongoing work to protect radiation workers on Earth. In the future, we will depend on counsel from ICRP to protect extraterrestrial workers and to enable the exploration of deep space.

Medical Event Management for Future Deep Space Exploration Missions to Mars.

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.

Operationally Relevant Behavior Assessment Using the Robotic On-Board Trainer for Research (ROBoT-r).

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.

Operational and Experimental Tasks, Performance, and Voice in Space.

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.