Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Astronauts”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1995

Role of the astronaut in operating the Advanced Fluid Physics Module.

The role of man in space is investigated in the operation of the Advanced Fluid Physics Module (AFPM), a scientific instrument dedicated to fluid physics research in a microgravity environment and flown on the Spacelab D2 mission. The astronaut involvement is addressed by applying the criteria of the THURIS study, conducted by NASA for the optimization of future manned space flights. Outcomes of the THURIS study are first summarized. The AFPM characteristics and interfaces are briefly presented. The five experiments performed on board Spacelab D2 are introduced and the involvement of the astronaut is described. Finally, THURIS criteria are applied to an AFPM experiment scenario. Results show that, of all the activities involved in the AFPM nominal operation, two thirds are related to hardware manipulation and to procedure following, while the last third uses the unique astronaut intellectual capabilities, making his presence in orbit mandatory for successful experiment completion.

Astronauts↗
PubMed1999

Radiation exposure limits for Japanese astronauts.

Starting in 2001, Japanese astronauts will live aboard the International Space Station (ISS) for 3 to 6 months a year. For astronauts, space radiation is primarily hazardous. Therefore, the National Space Development Agency of Japan (NASDA) is developing a system for Space Radiation Safety Operations. This report describes our overall image of Space Radiation Safety Operations aboard the ISS, especially our proceedings in drafting the "Space Radiation Exposure Limits for Japanese ISS Astronauts."

Adult↗
PubMed1996

Radiation-induced chromosome damage in astronauts' lymphocytes.

The increased number of manned space missions has made it important to estimate the biological risks encountered by astronauts. As they are exposed to cosmic rays, especially ions with high linear energy transfer (LET), it is necessary to estimate the doses they receive. The most sensitive biological dosimetry used is based on the quantification of radiation-induced chromosome damage to human lymphocytes. After the space missions ANTARES (1992) and ALTAIR (1993), we performed cytogenetic analysis of blood samples from seven astronauts who had spent from 2 weeks to 6 months in space. After 2 or 3 weeks, the X-ray equivalent dose was found to be below the cytogenetic detection level of 20 mGy. After 6 months, the biological dose greatly varied among the astronauts, from 95 to 455 mGy equivalent dose. These doses are in the same range as those estimated by physical dosimetry (90 mGy absorbed dose and 180 mSv equivalent dose). Some blood cells exhibited the same cytogenetic pattern as the 'rogue cells' occasionally observed in controls, but with a higher frequency. We suggest that rogue cells might result from irradiation with high-LET particles of cosmic origin. However, the responsibility of such cells for the long-term effects of cosmic irradiation remains unknown and must be investigated.

Astronauts↗
PubMed1997

Chromosomal aberrations in blood lymphocytes of astronauts after long-term space flights.

PURPOSE: To analyse lymphocyte chromosomes from astronauts of MIR and EUROMIR missions. MATERIALS AND METHODS: Peripheral lymphocytes from seven astronauts before and after space flights were cultured and analysed for structural chromosomal aberrations. RESULTS: Chromosome-type but not chromatid-type aberrations were significantly elevated after space flights when compared to pre-flight values. In one astronaut two rogue cells were found. CONCLUSIONS: Overall the frequencies of aberrations were found to be correlated with estimated absorbed cosmic radiation doses.

Astronauts↗
PubMed1995

Variations in astronaut radiation exposure due to anisotropic shield distribution.

The dose incurred in an environment generated by extraterrestrial space radiations within an anisotropic shield distribution depends on the orientation of the astronaut's body relative to the shield geometry. The fluctuations in exposure of specific organ sites due to astronaut re-orientation are found to be a factor of 2 or more in a typical space habitation module and typical space radiations. An approximation function is found that overestimates astronaut exposure in most cases studied and is recommended as a shield design guide for future deep space missions.

Astronauts↗
PubMed2004

Postflight balance control recovery in an elderly astronaut: a case report.

OBJECTIVE: To examine the sensorimotor adaptive response of a 77-year-old man exposed to the gravito-inertial challenges of orbital space flight. STUDY DESIGN: Prospective case study with retrospective comparisons. SETTING: NASA Neurosciences Laboratory (Johnson Space Center) and Baseline Data Collection Facility (Kennedy Space Center). PRIMARY PARTICIPANT: One 77-year-old male shuttle astronaut. INTERVENTION: Insertion into low Earth orbit was used to remove gravitational stimuli and thereby trigger sensorimotor adaptation to the microgravity environment. Graviceptor stimulation was reintroduced at landing, and sensorimotor readaptation to the terrestrial environment was tracked to completion. MAIN OUTCOME MEASURES: Computerized dynamic posturography tests were administered before and after orbital flight to determine the magnitude and time course of recovery. RESULTS: The elderly astronaut exhibited balance control performance decrements on landing day; however, there were no significant differences between his performance and that of younger astronauts tested on the same shuttle mission or on previous shuttle missions of similar duration. CONCLUSIONS: These results demonstrate that the physiological changes attributed to aging do not necessarily impair adaptive sensorimotor control processes.

Adaptation, Physiological↗
PubMed2005

Stability of chromosome aberrations in the blood lymphocytes of astronauts measured after space flight by FISH chromosome painting.

Follow-up measurements of chromosome aberrations in the blood lymphocytes of astronauts were performed by FISH chromosome painting at various intervals from 5 months to more than 5 years after space flight and compared to preflight baseline measurements. For five of the six astronauts studied, the analysis of individual time courses for translocations revealed a temporal decline of yields with half-lives ranging from 10 to 58 months. The yield of exchanges remained unchanged for the sixth astronaut during an observation period of 5 months after flight. These results may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure.

Astronauts↗
PubMed2005

Interventions to prevent bone loss in astronauts during space flight.

This paper reviews the interventions to stabilize calcium balance and bone metabolism and prevent bone loss in astronauts during space flight. Weightlessness during space flight results in calcium, vitamin D, and vitamin K deficiency, increases urinary calcium excretion, decreases intestinal calcium absorption, and increases serum calcium level, with decreased levels of serum parathyroid hormone and calcitriol. Bone resorption is increased, whereas bone formation is decreased. The loss of bone mineral density (BMD) in the spine, femoral neck and trochanter, and pelvis is 1.0-1.6% per month. High calcium intake and vitamin D supplementation during space flight does not affect bone metabolism, but prevents an elevation of serum calcium level through increased calcitriol level, while vitamin K counteracts the reduction in bone formation. However, there are no data to show the efficacy of pharmaceutical agents for prevention of development of osteoporosis in astronauts during flight, although the preventative effect of bisphosphonates, testosterone, and vitamin K2 on cancellous bone loss in the tibia or BMD loss in the hindlimb was reported in tail-suspended mature rats. It still remains uncertain whether these agents can prevent cortical bone loss caused by weightlessness in tail-suspended rats. Therefore, in addition to calcium, vitamin D, and vitamin K supplementation, agents that have both potent anti-resorptive and anabolic effects on cancellous and cortical bone may be needed to stabilize calcium balance and bone metabolism and prevent bone loss in astronauts during space flight.

Aerospace Medicine↗
PubMed1999

Incidence of Epstein-Barr virus in astronaut saliva during spaceflight.

BACKGROUND: Astronauts experience psychological and physical stresses that may result in reactivation of latent viruses during space-flight, potentially increasing the risk of disease among crewmembers. HYPOTHESIS: The shedding of Epstein-Barr virus (EBV) in the saliva of astronauts will increase during spaceflight. METHODS: A total of 534 saliva specimens were collected from 11 EBV-seropositive astronauts before, during, and after four space shuttle missions. The presence of EBV DNA in saliva, assessed by polymerase chain reaction (PCR), was used to determine shedding patterns before, during, and after space-flight. RESULTS: EBV DNA was detected more frequently before flight than during (p < 0.001) or after (p < 0.01) flight. No significant difference between the inflight and postflight periods was detected in the frequency of occurrence of EBV DNA. CONCLUSIONS: The increased frequency of shedding of EBV before flight suggests that stress levels may be greater before launch than during or after spaceflight.

Analysis of Variance↗
PubMed2000

Effectiveness of an expert system for astronaut assistance on a sleep experiment.

BACKGROUND: Principal Investigator-in-a-Box ([PI]) is an expert system designed to train and assist astronauts with the performance of an experiment outside their field of expertise, particularly when contact with the Principal Investigators on the ground is limited or impossible. In the current case, [PI] was designed to assist with the calibration and troubleshooting procedures of the Neurolab Sleep and Respiration Experiment. [PI] displays physiological signals in real time during the pre-sleep instrumentation period, alerts the astronauts when a poor signal quality is detected, and displays steps to improve quality. METHODS: Two studies are presented in this paper. In the first study 12 subjects monitored a set of prerecorded physiological signals and attempted to identify any signal artifacts appearing on the computer screen. Every subject performed the experiment twice, once with the assistance of [PI] and once without. The second part of this study focuses on the postflight analysis of the data gathered from the Neurolab Mission. After replaying the physiological signals on the ground, the frequency of correct [PI] alerts and false alarms (i.e., incorrect diagnoses by the expert system) was determined in order to assess the robustness and accuracy of the rules. CONCLUSIONS: Results of the ground study indicated a beneficial effect of [PI] and training in reducing anomaly detection time and the number of undetected anomalies. For the in-flight performance, excluding the saturated signals, the expert system had an 84% detection accuracy, and the questionnaires filled out by the astronauts showed positive crew reactions to the expert system.

Adult↗
PubMed1993

European astronaut training in Houston.

Three European astronauts are currently training as Space Shuttle Mission Specialists at NASA's Johnson Space Center in Houston. Two of the astronauts, Maurizio Cheli and Jean-Francois Clervoy, recently became members of NASA's 'astronaut pool' and have entered the Advanced Training phase. The third one, Claude Nicollier, is now preparing for the mission to service the Hubble Space Telescope in December.

Astronauts↗
PubMed2001

Mechanistic bases for modelling space radiation risk and planning radiation protection of astronauts.

The approaches generally adopted for planning radiation protection in ground-based facilities cannot be applied straightforward for astronaut protection in space. Indeed in such extreme conditions, modelling methods and shielding design must be based on a detailed mechanistic knowledge of the peculiar astronauts irradiation conditions. Great help can derive from mechanistic modelling, generally aimed to better understand the intermediate steps leading from the initial energy depositions to different biological endpoints, up to organ and organism level. In the present work, criteria will be illustrated for using mechanistic approaches in developing practical tools for astronauts radioprotection, once the external field and the interaction cross sections with the spacecraft walls are known; particular attention will be given to the treatment of mixed fields. Techniques for integrating into condensed-history codes stochastic information provided by event-by-event simulations will be presented.

Aerospace Medicine↗
PubMed2003

[Measure on medical care and rescue for the first Chinese astronaut during manned space flight].

OBJECTIVE: To discuss the experience of medical care and rescue for the first Chinese astronaut during manned space flight. METHODS: Review the experiences of foreign nations in respect to accidental injuries of astronaut during manned space flight, the possible reasons were analyzed, and accordingly a reasonable and effective prophylactic measures and health care were formulated. RESULTS: An effective mobile intensive care unit (ICU) was established on desert or prairie where the capsule would land, so as to ensure the safety of the first Chinese astronaut, and to provide intensive care as well as successful emergency treatment in case of accidental injuries. CONCLUSION: Reasonable and effective prophylactic measures and health care appear to be an important aspect of the successful manned space flight.

Accidents, Aviation↗
PubMedDate not supplied

[Pathogenetic mechanisms of the so-called astronauts' anemia].

The authors analyze the literature data published in the last 20 years on clinical, laboratory, physiological, hematological and biochemical evidence obtained at preflight and postflight examinations of astronauts and experimental animals who spent 5-12 months in space. After space flights the astronauts exhibited a noticeable decrease in red cell mass, in reticulocyte count, hemoglobin and erythropoietin levels (associated with hypochromia and hyposideremia). This condition of erythron in microgravity is termed astronauts' anemia. The authors consider such anemia as an adaptive erythrocytopenic microgravity syndrome with complicated pathogenesis and suggest its model in the form of acquired transitory thalassemia.

Anemia↗
PubMed1996

The use of IQ assessment in astronaut screening and evaluation.

BACKGROUND: The screening and evaluation of astronaut candidates usually includes measures of cognitive and intellectual capacity. Questions of ceiling effects and discriminability when evaluating individuals assumed to be of above average intelligence should be considered. The current study examines ceiling effects and discriminability on IQ assessment between pilots vs. mission specialists and men vs. women in the selection of astronaut candidates. METHODS: IQ scores on 104 male and female Shuttle astronaut candidates as measured by the Multidimensional Aptitude Battery (MAB) were analyzed via factor analyses and tests of differences between genders, selection status, and job types. Total group, gender, and job type specificity and sensitivity and overall percent correctly classified were assessed on selected vs. unselected classification. RESULTS: Exploratory and confirmatory factor analyses failed to replicate the proposed factor configuration prompting reconfigured domain scores. Analyses of differences between gender, selection, and job categories found different results when using reconfigured IQ scores compared to the original formulation. The 10 subscales performed better than overall domain scores in sensitivity, specificity, and as significant predictors of individuals selected. Both versions of Verbal, Performance, and Full Scale IQ scores performed similarly regarding sensitivity and specificity. The reconfigured scores were better predictors of selection. DISCUSSION: Evidence for sensitivity, specificity, and classification prediction was better for subscales than overall domain scores. Some consideration to using reconfigured domain scores should be given to increase instrument utility.

Aptitude Tests↗
PubMedDate not supplied

Peripheral leukocyte subpopulations and catecholamine levels in astronauts as a function of mission duration.

OBJECTIVE: The objective of this study was to determine the effects of spaceflight duration on immune cells and their relationship to catecholamine levels. METHODS: Eleven astronauts who flew aboard five different US Space Shuttle flights ranging in duration from 4 to 16 days were studied before launch and after landing. RESULTS: Consistent with prior studies, spaceflight was associated with a significant increase in the number of circulating white blood cells (p <.01), including neutrophils (p <.01), monocytes (p <.05), CD3+CD4+ T-helper cells (p <.05), and CD19+ B cells (p <.01). In contrast, the number of CD3-CD16+56+ natural killer cells was decreased (p <.01). Plasma norepinephrine levels were increased at landing (p <.01) and were significantly correlated with the number of white blood cells (p <.01), neutrophils (p <.01), monocytes (p <.01), and B cells (p <.01). Astronauts who were in space for approximately 1 week showed a significantly larger increase on landing in plasma norepinephrine (p =.02) and epinephrine (p =.03) levels, as well as number of circulating CD3+CD4+ T-helper cells (p <.05) and CD3+CD8+ T-cytotoxic cells (p <.05) as compared with astronauts in space for approximately 2 weeks. CONCLUSIONS: The data suggest that the stress of spaceflight and landing may lead to a sympathetic nervous system-mediated redistribution of circulating leukocytes, an effect potentially attenuated after longer missions.

Catecholamines↗
PubMed1999

[Temperature environment and the heat exchange of astronaut in the emergency landing areas].

OBJECTIVE: To analyze the temperature environment of different emergency landing areas and discuss the heat exchange between astronaut and the temperature environment. In addition, countermeasures against the emergency temperature environment were discussed. METHOD: Heat exchange equation between man and environment was built using the law of energy conservation, and factors that affect the heat balance of human body were discussed. RESULT: It was found that temperature, humidity, air pressure, velocity of wind and solar radiation are factors affecting the thermal balance of the astronaut. CONCLUSION: It is important for an astronaut to act properly and use the living devices and the environment conditions correctly during the emergency landing.

Body Temperature Regulation↗
PubMed1991

Psychiatric diagnoses in a group of astronaut applicants.

Between 1959 and 1987, the psychiatric evaluation of astronaut candidates evolved from a 30-h intensive examination evaluating applicants for psychopathology, and studying their performance under stress, to a 2-h clinical interview whose structure and contents were determined by the individual examiner. Evaluations done during these years applied both psychiatric (or, "select-out") criteria and psychological (or, "select-in") criteria. In an attempt to more rigorously define the psychiatric, "select-out" component, a standardized, semi-structured clinical interview was developed to identify the presence or history of psychiatric disorders listed in the Diagnostic and Statistical Manual of Mental Disorders, 3rd Ed. ("DSM-III"). A total of 117 astronaut applicants underwent this clinical interview as part of a comprehensive medical evaluation during a recent astronaut selection. Of the 117 applicants, 9 (7.7%) met DSM-III criteria for a variety of Axis I and Axis II diagnoses, including V-code diagnoses.

Aerospace Medicine↗