Extended Space Missions Research Articles

Aeronautics in dentistry: Navigating oral health challenges in zero gravity

Space, an expansive environment beyond Earth’s atmosphere, poses challenges for astronauts and spacecraft due to microgravity and radiation. These conditions disrupt saliva production, alter oral microbial composition, and challenge hygiene practices, leading to oral health concerns such as dental caries, periodontal diseases, and discomfort. Astronauts also face risks such as masticatory muscle atrophy and oral cancer during extended space missions. Thus, comprehensive dental care in space is crucial for astronaut well-being and overall health as humanity explores farther into space. This review delves into these challenges, exploring strategies to maintain optimal oral health during space travel and advancements in dental practices for astronauts on prolonged missions.

The human body in different spaces

Space Medicine has revolutionized the way of understanding human physiology in extra-terrestrial environments, such as microgravity. Research in this field attempts to maintain synchrony between scientific and medical development, with the goal of improving the overall health and performance of astronauts. Engineering also plays a crucial role in the design of spacecraft and spacesuits to ensure the safety and health of astronauts on extended missions to the Moon and Mars. Radiation exposure in space poses health concerns, but strategies such as radiation control and shielding are being implemented to mitigate these risks. NASA is actively investigating how the human body reacts to long-duration spaceflight, with the goal of preparing for future extended space missions.

Effects of simulated space conditions on CD4+ T cells: a multi modal analysis.

The immune system is an intricate network of cellular components that safeguards against pathogens and aberrant cells, with CD4+ T cells playing a central role in this process. Human space travel presents unique health challenges, such as heavy ion ionizing radiation, microgravity, and psychological stress, which can collectively impede immune function. The aim of this research was to examine the consequences of simulated space stressors on CD4+ T cell activation, cytokine production, and gene expression. CD4+ T cells were obtained from healthy individuals and subjected to Fe ion particle radiation, Photon irradiation, simulated microgravity, and hydrocortisone, either individually or in different combinations. Cytokine levels for Th1 and Th2 cells were determined using multiplex Luminex assays, and RNA sequencing was used to investigate gene expression patterns and identify essential genes and pathways impacted by these stressors. Simulated microgravity exposure resulted in an apparent Th1 to Th2 shift, evidenced on the level of cytokine secretion as well as altered gene expression. RNA sequencing analysis showed that several gene pathways were altered, particularly in response to Fe ions irradiation and simulated microgravity exposures. Individually, each space stressor caused differential gene expression, while the combination of stressors revealed complex interactions. The research findings underscore the substantial influence of the space exposome on immune function, particularly in the regulation of T cell responses. Future work should focus expanding the limited knowledge in this field. Comprehending these modifications will be essential for devising effective strategies to safeguard the health of astronauts during extended space missions. The effects of simulated space stressors on CD4+ T cell function are substantial, implying that space travel poses a potential threat to immune health. Additional research is necessary to investigate the intricate relationship between space stressors and to develop effective countermeasures to mitigate these consequences.

Assessing black soldier fly pupation and survival in lunar regolith simulant: Implications for sustainable controlled habitats on the Moon

Bioregenerative life-support systems (BLSSs) will be crucial for extended space missions and extraterrestrial habitats. The black soldier fly, Hermetia illucens, is recognized for its efficient organic waste consumption, making it well-suited for closed environments like spacecraft. Our study assessed H. illucens adaptability to different substrates, including a lunar regolith simulant, pertinent to future lunar colonization. Remarkably resilient, H. illucens prepupal larvae successfully pupated in all tested substrates, but pupation timing varied, with no-substrate larvae pupating later. Pupal stage duration also differed, particularly with lunar regolith simulant and sand treatments resulting in longer durations. Substrate treatments significantly influenced the number of emerged adults, with lunar regolith simulant yielding more adults than the no-substrate treatment. Additionally, sand and wood shavings treatments produced more adults, highlighting H. illucens adaptability to various substrates, including lunar regolith. These findings are crucial for future BLSSs design. Additionally, H. illucens adaptability to lunar regolith provides insights into life's adaptability in space environments, guiding future experiments on celestial bodies. This study provides critical data on how different substrates, including lunar regolith simulants, influence H. illucens development and survival, advancing BLSSs and ecological science in both space and terrestrial contexts.

Understanding the complexities of space anaemia in extended space missions: revelations from microgravitational odyssey.

Space travel exposes astronauts to several environmental challenges, including microgravity and radiation exposure. To overcome these stressors, the body undergoes various adaptations such as cardiovascular deconditioning, fluid shifts, metabolic changes, and alterations in the state of the bone marrow. Another area of concern is the potential impact of these adaptations on erythrocyte and haemoglobin concentrations, which can lead to what is commonly referred to as space anaemia or microgravity-induced anaemia. It is known that anaemia may result in impaired physical and cognitive performance, making early detection and management crucial for the health and wellbeing of astronauts during extended space missions. However, the effects and mechanisms of space anaemia are not fully understood, and research is underway to determine the extent to which it poses a challenge to astronauts. Further research is needed to clarify the long-term effects of microgravity on the circulatory system and to investigate possible solutions to address spaceflight-induced anaemia. This article reviews the potential link between spaceflight and anaemia, based on existing evidence from simulated studies (e.g., microgravity and radiation studies) and findings from spaceflight studies (e.g., International Space Station and space shuttle missions).

Microbial products for space nutrition

Sustainably producing nutrients beyond Earth is one of the biggest technical challenges for future extended human space missions. Microorganisms such as microalgae and cyanobacteria can provide astronauts with nutrients, pharmaceuticals, pure oxygen, and bio-based polymers, making them an interesting resource for constructing a circular bioregenerative life support system in space.

Oral Health in Zero Gravity: A Comprehensive Review of Orofacial Effects and Countermeasures in Spaceflights.

Space is a complex and challenging setting encompassing the region beyond Earth's atmosphere where astronauts and spacecraft operate. The unique conditions of spaceflights, particularly microgravity and radiation, pose significant challenges to astronaut health, including the orofacial region. It has effects on saliva production, microbial composition, and oral hygiene practices, which influence oral health status, such as increased risk of dental caries, gum diseases, oral discomfort, temporomandibular joint dysfunctions, sialoliths, painand dysesthesia in the teeth and oral mucosa, masticatory muscle atrophy, and oral cancer which can be detrimental during prolonged missions. Hence, a comprehensive approach to dental care in space is imperative to ensure astronauts' well-being and overall health as we strive to extend our presence beyond Earth. This literature review paper sheds light on the intricate effects of space on the orofacial region and delves into the unique challenges astronauts face in upholding optimal oral health while in space. It explores the current state of dentistry in space and discusses advancements and strategies that aim to maintain optimal oral health for astronauts during extended space missions.

Simulation study on total ionizing dose effect of IGBT gamma irradiation

The insulated gate bipolar transistor (IGBT) has emerged as a prominent high-power semiconductor device due to its excellent overall performance. It is widely utilized in various fields, including aerospace. Due to prolonged operation in complex irradiation environments, the performance of IGBTs is susceptible to degradation and damage. Therefore, conducting research on the variation of IGBT characteristics under irradiation environments is crucial to ensuring their long-term functionality in extended space missions. To evaluate and analyze the total ionizing dose (TID) effect of IGBTs during operation, this study adopts a trench IGBT as the device model. Utilizing the finite element method, technology computer-aided design (TCAD) is employed to simulate and analyze the electrical characteristic changes of IGBTs under different total radiation doses. The simulation results are subsequently validated through theoretical analysis. The simulation results indicate that gamma radiation significantly affects the overall electrical characteristics of IGBTs.

Crew Interaction in Extended Space Missions

Detection of the extent of common values in a cohesive space crew has become an important trend in modern space psychology. It is known from the works of Ch. Osgood that the semantic differential scale is a reliable way to obtain objective information on the emotional attitudes towards a topic of interest. Within the frame of the Russian space experiment “Interactions” on the International Space Station (ISS), a computerized survey, the Personal Self-Perception and Attitudes (PSPA), was developed for analyzing the subjects’ emotional attitudes toward their social environment. In the course of the PSPA procedure, the crewmembers rate each other and themselves (in the past, present, and future) using the criteria previously personally chosen. These criteria should be regarded as their personal values. A total of 30 subjects have already completed the study on board the ISS. The main tasks of the study are: (1) to define individual and group values and the extent of group identification reflected in sharing these values; (2) to determine the impact of cross-cultural factors on mutual perceptions and self-perceptions in space crews and with the Mission Control Center (MCC); (3) to study changes in the space crews’ group cohesiveness and structure as they are exposed to the stress of the extended space mission environment. The data obtained indicate an increase in a “psychological distance” between the crew and the MCC personnel versus increased crew cohesion. The results gained made it possible to identify the most significant categories of values common to the subjects from the professional cosmonaut group. The priority of these shared values for each subject is an important condition for the formation of a cohesive crew.

Unveiling the Genetic Frontier: CRISPR as a Tool for Investigating Space Travels Impact on Human Physiology

Gene editing technologies, such as CRISPR, present significant potential in unraveling the effects of space travel on the human body. By employing gene manipulation techniques in model organisms, researchers can delve into the intricate influence of specific genes on adaptation to space environments, radiation resistance, and other crucial factors pertinent to extended space missions. Furthermore, the utilization of model organisms provides a valuable tool for simulating space conditions and physiological alterations. This paper highlights the significance of gene editing technologies in space research, emphasizing their ability to unravel genetic mechanisms underlying physiological changes in response to space conditions.

Co-adaptation of Streptococcus mutans to simulated microgravity and silver nitrate

To sustain life on extended space missions, it is essential to maintain clean potable water. NASA currently uses iodine as the primary biocide in the potable water dispenser on the International Space Station and has recently proposed a potential switch to silver-based antimicrobials. Streptococcus mutans is the primary etiological agent of dental caries, part of the normal oral flora, and would endure direct exposure to water from the potable water dispenser. In our previous work, we examined the 100-day adaptive response of Streptococcus mutans to simulated microgravity (sMG). Here, we examined the evolutionary co-adaptation of S. mutans under sMG and silver nitrate (AgNO3) to evaluate the consequences of using silver as a primary biocide in space and the impact on the evolution of microbes from the oral microbiome. To do this, we adapted four populations of S. mutans under sMG and co-adapted four populations in simulated microgravity and silver nitrate using high-aspect ratio vessels for 100 days. Genomic analysis at multiple time points showed that S. mutans in sMG evolved variants consistent with our previous findings (SMU_1307c and SMU_399) while also acquiring novel mutations in the glutathione reductase gorA. The co-adapted populations showed mutations specific for the environment in ciaH/R, PBP1a, trkA, and trkB. We also assessed virulence phenotypes, and while simulated microgravity increased antibiotic susceptibility, sucrose-dependent adhesion, and, in some populations, acid tolerance, co-adaptation to silver nitrate reversed these effects. Overall, these data show that the use of silver as a biocide in simulated microgravity can evolve strains with novel genotypic and phenotypic traits that could alter virulence.

ИССЛЕДОВАНИЕ ПРОБИОТИЧЕСКОЙ АКТИВНОСТИ АУТОШТАММОВ LACTOBACILLACEAE, ВОССТАНОВЛЕННЫХ ПОСЛЕ ДЛИТЕЛЬНОЙ КРИОКОНСЕРВАЦИИ В ЭКСПЕРИМЕНТЕ С ИЗОЛЯЦИЕЙ

A comprehensive investigation of auto-probiotic prophylaxis of dysbiosis symptoms included, testing the methods of prolonged preservation of human microbial associations, and their potential use as probiotic substances during long-term isolation. The investigation was performed in a 14-d isolation study with participation of 6 human subjects. Over 7 days starting from the day of egress, 4 subjects consumed a priobiotic beverage, i.e. kefir supplemented for each one with own isolated Lactobacillaceae strains. Two subjects did not receive probiotic beverages. In the group of subjects who had consumed kefirs the number of lactobacilli stabilized. An increased number of Bacillus spp. and Bifidobacterium spp. and a decreased number of enterococci imply the benefits from the autoprobiotic beverage. After the egress, the upper airway (UA) microflora decreased abruptly; however, rise of the dyspnea index by the end of kefir consumption suggested UA microflora stabilization. Feces analysis after 6-month cryopreservation at –80 ºС showed that opportunistic microorganisms decreased considerably in samples of all subjects. Noteworthy is that numbers of Lactobacillaceae before and after cryopreservation did not differ much and reductions in Bifidobacterium spp. and E. coli were within the physiological norm margins. Our cryopreservation findings attest to potential applicability of the technology in extended space missions for preserving the intestinal bacteria consortium to be used for mixing autoprobiotic substances.

Gut microbiome and human health under the space environment

The gut microbiome is well recognized to have a pivotal role in regulation of the health and behaviour of the host, affecting digestion, metabolism, immunity, and has been linked to changes in bones, muscles and the brain, to name a few. However, the impact of microgravity environment on gut bacteria is not well understood. In space environments, astronauts face several health issues including stress, high iron diet, radiation and being in a closed system during extended space missions. Herein, we discuss the role of gut bacteria in the space environment, in relation to factors such as microgravity, radiation and diet. Gut bacteria may exact their effects by synthesis of molecules, their absorption, and through physiological effects on the host. Moreover we deliberate the role of these challenges in the dysbiosis of the human microbiota and possible dysregulation of the immune system.

3D Printing in Zero G Technology Demonstration Mission: Complete Experimental Results and Summary of Related Material Modeling Efforts.

In 2014, NASA, in partnership with Made In Space, Inc., launched the first 3D printer to the International Space Station. Results of the first phase of operations for this mission demonstrated use of the fused filament fabrication (FFF) process for 3D printing in a microgravity environment. Previously published results indicated differences in density and mechanical properties of specimens printed in microgravity and those manufactured with the printer prior to its launch to ISS. Based on extensive analyses, these differences were hypothesized to be a result of subtle changes in manufacturing process settings rather than a microgravity influence on the FFF process. Phase II operations provided an opportunity to produce additional specimens in microgravity, evaluate the impact of changes in the extruder standoff distance, and ultimate provide a more rigorous assessment of microgravity effects through control of manufacturing process settings. Based on phase II results and a holistic consideration of phase I and phase II flight specimens, no engineering-significant microgravity effects on the process are noted. Results of accompanying material modeling efforts, which simulate the FFF process under a variety of conditions (including microgravity), are also presented. No significant microgravity effects on material outcomes are noted in the physics-based model of the FFF process. The 3D printing in zero G technology demonstration mission represents the first instance of off-world manufacturing. It represents the first step toward transforming logistics for long duration space exploration and is also an important crew safety enhancement for extended space missions where cargo resupply is not readily available. This paper presents the holistic results of phase I and II on-orbit operations and also includes material modeling efforts.

A study of voice production characteristics of astronuat speech during Apollo 11 for speaker modeling in space.

Human physiology has evolved to accommodate environmental conditions, including temperature, pressure, and air chemistry unique to Earth. However, the environment in space varies significantly compared to that on Earth and, therefore, variability is expected in astronauts' speech production mechanism. In this study, the variations of astronaut voice characteristics during the NASA Apollo 11 mission are analyzed. Specifically, acoustical features such as fundamental frequency and phoneme formant structure that are closely related to the speech production system are studied. For a further understanding of astronauts' vocal tract spectrum variation in space, a maximum likelihood frequency warping based analysis is proposed to detect the vocal tract spectrum displacement during space conditions. The results from fundamental frequency, formant structure, as well as vocal spectrum displacement indicate that astronauts change their speech production mechanism when in space. Moreover, the experimental results for astronaut voice identification tasks indicate that current speaker recognition solutions are highly vulnerable to astronaut voice production variations in space conditions. Future recommendations from this study suggest that successful applications of speaker recognition during extended space missions require robust speaker modeling techniques that could effectively adapt to voice production variation caused by diverse space conditions.

Gravity and Neuronal Adaptation

Introduction: For interplanetary and orbital missions in human space flight, knowledge about the gravity-sensitivity of the central nervous system (CNS) is required. The objective of this study was to assess neurophysiological correlates in variable hetero gravity conditions in regard to their timing and shaping. Methods: In ten subjects, peripheral nerve stimulation was used to elicit H-reflexes and M-waves in the M. soleus in Lunar, Martian, Earth and hypergravity. Gravity-dependencies were described by means of reflex latency, inter-peak-interval, duration, stimulation threshold and maximal amplitudes. Experiments were executed during the CNES/ESA/DLR JEPPFs. Results: H-reflex latency, inter-peak-interval and duration decreased with increasing gravitation (P<0.05); likewise, M-wave inter-peak-interval was diminished and latency prolonged with increasing gravity (P<0.05). Stimulation threshold of H-reflexes and M-waves decreased (P<0.05) while maximal amplitudes increased with an increase in gravitation (P<0.05). Conclusion: Adaptations in neurophysiological correlates in hetero gravity are associated with a shift in timing and shaping. For the first time, our results indicate that synaptic and axonal nerve conduction velocity as well as axonal and spinal excitability are diminished with reduced gravitational forces on the Moon and Mars and gradually increased when gravitation is progressively augmented up to hypergravity. Interrelated with the adaptation in threshold we conclude that neuronal circuitries are significantly affected by gravitation. As a consequence, movement control and countermeasures may be biased in extended space missions involving transitions between different force environments.

3D Printed Surgical Instruments Evaluated by a Simulated Crew of a Mars Mission.

The first space-based fused deposition modeling (FDM) 3D printer became operational in 2014. This study evaluated whether Mars simulation crewmembers of the Hawai'i Space Exploration Analog and Simulation (HI-SEAS) II mission with no prior surgical experience could utilize acrylonitrile butadiene styrene (ABS) thermoplastic surgical instruments FDM 3D printed on Earth to complete simulated surgical tasks. This study sought to examine the feasibility of using 3D printed surgical tools when the primary crew medical officer is incapacitated and the back-up crew medical officer must conduct a surgical procedure during a simulated extended space mission. During a 4 mo duration ground-based analog mission, five simulation crewmembers with no prior surgical experience completed 16 timed sets of simulated prepping, draping, incising, and suturing tasks to evaluate the relative speed of using four ABS thermoplastic instruments printed on Earth compared to conventional instruments. All four simulated surgical tasks were successfully performed using 3D printed instruments by Mars simulation crewmembers with no prior surgical experience. There was no substantial difference in time to completion of simulated tasks with control vs. 3D printed sponge stick, towel clamp, scalpel handle, and toothed forceps. These limited findings support further investigation into the creation of an onboard digital catalog of validated 3D printable surgical instrument design files to support autonomous, crew-administered healthcare on Mars missions. Future work could include addressing sterility, biocompatibility, and having astronaut crew medical officers test a wider range of surgical instruments printed in microgravity during actual surgical procedures. Wong JY, Pfahnl AC. 3D printed surgical instruments evaluated by a simulated crew of a Mars mission. Aerosp Med Hum Perform. 2016; 87(9):806-810.

Prediction of transits of Solar system objects inKepler/K2 images: an extension of the Virtual Observatory service SkyBoT

All the fields of the extended space mission Kepler/K2 are located within the ecliptic. Many solar system objects thus cross the K2 stellar masks on a regular basis. We aim at providing to the entire community a simple tool to search and identify solar system objects serendipitously observed by Kepler. The SkyBoT service hosted at IMCCE provides a Virtual Observatory (VO) compliant cone-search that lists all solar system objects present within a field of view at a given epoch. To generate such a list in a timely manner, ephemerides are pre-computed, updated weekly, and stored in a relational database to ensure a fast access. The SkyBoT Web service can now be used with Kepler. Solar system objects within a small (few arcminutes) field of view are identified and listed in less than 10 sec. Generating object data for the entire K2 field of view (14{\deg}) takes about a minute. This extension of the SkyBot service opens new possibilities with respect to mining K2 data for solar system science, as well as removing solar system objects from stellar photometric time-series.

Cosmonauts’ tolerance of the chest-back G-loads during ballistic and automatically controlled descents of space vehicles

Analysis of cosmonauts' +Gx tolerance on the stage of ballistic or automatically controlled Soyuz descent after missions to the International space station of varying duration was performed. As compared with automatically controlled descents, tolerance of descent re-entry +G(x) following short (8-14 d) missions was marked by reliably more frequent instances of visual disorders, difficult breathing, sensation of a lump in the throat and vestibulovegetative disorders (p < 0.05). The ballistic but not controlled re-entry after long-term mission provoked visual disorders, difficulties with breathing and speech, and vestibulovegetative disorders more often (p < 0.05). A considerable HR rise due to the ballistic rather than control descent was associated with re-entry and the main parachute re-hooking for symmetrical suspension; respiration rate was the highest during parachuting. By and large, these factual data infer that the ballistic descent after various periods in spaceflight microgravity, especially after extended space missions (164-169 d), led to a dramatic loss in the body functional reserves.

Broad-spectrum antibiotic or G-CSF as potential countermeasures for impaired control of bacterial infection associated with an SPE exposure during spaceflight.

A major risk for astronauts during prolonged space flight is infection as a result of the combined effects of microgravity, situational and confinement stress, alterations in food intake, altered circadian rhythm, and radiation that can significantly impair the immune system and the body’s defense systems. We previously reported a massive increase in morbidity with a decrease in the ability to control a bacterial challenge when mice were maintained under hindlimb suspension (HS) conditions and exposed to solar particle event (SPE)-like radiation. HS and SPE-like radiation treatment alone resulted in a borderline significant increase in morbidity. Therefore, development and testing of countermeasures that can be used during extended space missions in the setting of exposure to SPE radiation becomes a serious need. In the present study, we investigated the efficacy of enrofloxacin (an orally bioavailable antibiotic) and Granulocyte colony stimulating factor (G-CSF) (Neulasta) on enhancing resistance to Pseudomonas aeruginosa infection in mice subjected to HS and SPE-like radiation. The results revealed that treatment with enrofloxacin or G-CSF enhanced bacterial clearance and significantly decreased morbidity and mortality in challenged mice exposed to suspension and radiation. These results establish that antibiotics, such as enrofloxacin, and G-CSF could be effective countermeasures to decrease the risk of bacterial infections after exposure to SPE radiation during extended space flight, thereby reducing both the risk to the crew and the danger of mission failure.