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PubMed1994

EVA: European plans.

The current status of European EVA (extravehicular activity) plans is reviewed. The major difference to already existing EVA scenarios in U.S.A. and Soviet Union consists in the adoption of a higher suit pressure, namely 500 hPa. The results of a study concerned with the physiological consequences of this adoption are presented, including recommendations for protective procedures and their necessary experimental validation. A certain discrepancy between laboratory experimental decompression data and EVA operational results is discussed, leading to the identification of several items which may influence space decompression. Microgravity and the influence of the space suit itself are most likely factors in the explanation of this discrepancy, and both experimental procedures and technological developments are proposed to clarify their role for the future design of EVA procedures.

Aerospace Medicine↗
PubMed1995

EVA-related activities in Japan.

Recognizing the importance and fertility of the extra vehicular activity technologies in future space development and utilization, some related research activities have been conducted in Japan, though it has not committed itself to developing its own manned space flight capability. The purpose of this paper is to introduce and evaluate these EVA-related activities and to indicate the next step for Japan to get into the era of manned space activities including EVA in reality.

Carbon Dioxide↗
PubMed1979

Importance of temperature control for HEFLEX, a biological experiment for Spacelab 1.

HEFLEX is an experiment in plant gravitational physiology now being developed for the Spacelab 1 Mission. Its object is to measure kinetic properties of plant nutation in a very low g environment. HEFLEX is designed to be scientifically compatible with restrictions imposed by engineering considerations. Among those restrictions one of the more important but one not necessarily well appreciated by mission engineers is the specification for spacelab air temperature. Development of the HEFLEX space experiment has been seriously complicated and the flight hardware significantly increased in cost as a result of the burden of insuring adequate temperature control being shifted from the spacelab module design to the biological experiment itself. The question is raised: Is this the most economical method of implementing biological research in space?

Adaptation, Physiological↗
PubMedDate not supplied

Ensuring of long operation life of the orbiting station EVA space suit.

Russia has gained a lot of experience in operating the space suits (SS) during the extravehicular activities (EVA) by the crews of SALYUT-6, SALYUT-7 and MIR orbiting stations. A total of 21 Orlan-type space suits of various models were operated onboard the orbiting stations (OS) during almost 20 years period. Some of these space suits served up to 3 years in orbit. The paper reviews special features of long SS operation (without return to the Earth) onboard an orbiting station as well as the problems associated with SS repeated use by several crews. An analysis of measures to support solving of the problems of SS long stay and reliable operation onboard the orbiting station is made: selection of a corresponding SS type and separate elements design; selection of the materials; routine and preventive maintenance; development tests. The advantages of the space suit of a semi-rigid type for solving the above problems are shown. The paper includes a short analysis of space suits' operation onboard the Russian orbiting station MIR, and some restuts of inspection of the Orlan-DMA space suit returned to the Earth from orbit by STS-79 alter long operation in orbit. Recommendations on further improvement of the space suits for EVA operations in the International Space Station (ISS) are given.

Decompression Sickness↗
PubMed2003

Ultrasound in space.

Physiology of the human body in space has been a major concern for space-faring nations since the beginning of the space era. Ultrasound (US) is one of the most cost effective and versatile forms of medical imaging. As such, its use in characterizing microgravity-induced changes in physiology is being realized. In addition to the use of US in related ground-based studies, equipment has also been modified to fly in space. This involves alteration to handle the stresses of launch and different power and cooling requirements. Study protocols also have been altered to accommodate the microgravity environment. Ultrasound studies to date have shown a pattern of adaptation to microgravity that includes changes in cardiac chamber sizes and vertebral spacing. Ultrasound has been and will continue to be an important component in the investigation of physiological and, possibly, pathologic changes occurring in space or as a result of spaceflight.

Aerospace Medicine↗
PubMedDate not supplied

Psychological, psychiatric, and interpersonal aspects of long-duration space missions.

America's future in space calls for manned missions that are of long duration and increasing complexity. Under these conditions, psychological and interpersonal stressors will take on added importance in affecting the safely of the crew and the outcome of the mission. Through an analysis of reports from manned American and Soviet space missions and Earth-bound simulations, several psychological, psychiatric, and interpersonal issues can be identified that could affect the success of the space station and other long-duration space ventures. Psychological issues include sleep problems, alteration in time sense, demographic effects, career motivation, transcendent experiences, homesickness, and alteration in perceptual sensitivities. Psychiatric issues include anxiety, depression, and psychosis, psychosomatic symptoms, emotional problems related to the stage of the mission, and postflight personality changes. Interpersonal issues include interpersonal tension, decreased cohesiveness over time, need for privacy, and task vs emotional leadership. Steps can be taken to minimize the impact of these issues, both before and during the mission.

Aerospace Medicine↗
PubMed2001

Psychosocial issues in space: future challenges.

As the duration of space flights increases and crews become more heterogeneous, psychosocial factors are likely to play an increasingly important role in determining mission success. The operations of the International Space Station and planning of interplanetary missions represent important future challenges for how to select, train and monitor crews. So far, empirical evidence about psychological factors in space is based on simulations and personnel in analog environments (i.e. polar expeditions, submarines). It is apparent that attempts to transfer from these environments to space requires a thorough analysis of the human behavior specific to the fields. Recommendations for research include the effects of multi-nationality on crew interaction, development of tension within crews and between Mission Control, and prediction of critical phases in adaptation over time. Selection of interpersonally compatible crews, pre-mission team training and implementation of tools for self-monitoring of psychological parameters ensure that changes in mission requirements maximize crew performance.

Adaptation, Psychological↗
PubMed1998

Operational psychology countermeasures during the Lunar-Mars Life Support Test Project.

The Crew and Thermal Systems Division at the NASA Johnson Space Center conducted a series of human-rated tests, termed the Lunar-Mars Life Support Test Project (LMLSTP), designed to advance technology in closed life support systems. As the duration of these tests lengthened, the psychological factors associated with placing humans in these environments became increasingly salient to successful mission completion. A number of psychological activities were conducted to ensure successful operations and protect crew member well-being, including individual crew member selection, crew composition, training and preparation, family inclusion, educational briefings, in-mission tracking, operational interventions, and postmission repatriation. This article describes these activities, the rationale behind their design, the similarities and differences to techniques utilized for spaceflight, and considerations related to designing psychological countermeasures for confined environments. In addition to testing physical and engineering systems, the LMLSTP series functioned as an effective testbed for developing operational concepts and countermeasures for extended space missions.

Adaptation, Psychological↗
PubMed1976

Study of space perception functioning during simulation of certain space flight factors.

The results are reported of spatial perception function studies in 130 healthy males of 17-35 years of age and in 33 people with complete or partial inhibition of the function of the labyrinth (deaf-mutes). The comparative magnitudes of gravitational vertical perception impairments were studied during vestibular stimulation (Coriolis and linear acceleration), as well as during clino-orthostatic and antiorthostatic hypokinesia. Hypokinesia to a certain extent permitted the simulation of the blood redistribution in weightlessness. The ability of the subjects to determine the subjective visual vertical was used as the test criterion. The experiments have shown that the magnitude of the observed changes in the human sensory area depends on the physical properties of the vestibular stimulus, on the angle of inclination of the head of the bed during hypokinesia and on the duration of bed rest, but not necessarily on the level of vestibular tolerance. Possible mechanisms of impairment of perception in the space flight environment are discussed. Examinations of spatial perception function are useful during selection procedures for astronauts and airmen.

Acceleration↗
PubMedDate not supplied

[Some physiological effects caused by 30 days of bed rest in different body positions].

Eighteen male test subjects were exposed to a 30-day bed rest with the foot end of the bed tilted at +6 degrees, -2 degrees or -6 degrees. Control subjects were allowed a normal mode of life during the same period of time. Hypokinesia was shown to play the leading role in the genesis of most changes, since control subjects displayed no changes. It was concluded that head-down tilt simulated changes occurring during adaptation to weightlessness better than recumbency or head-up tilt.

Adaptation, Physiological↗
PubMed1995

Long term stability of somatosensory evoked potentials and the effects of microgravity.

BACKGROUND: Exposure to microgravity causes a height increase of up to 70 mm that places traction on the spine and may possibly lead to spinal cord dysfunction. Somatosensory evoked potentials (SSEP) have been widely used to monitor spinal cord function. This study was carried out to determine the long-term stability of the latency of SSEP's in individual subjects and the feasibility of recording SSEP's in a microgravity environment. METHODS: Baseline values and variability of the latency of the cortical evoked potentials were established in seven subjects over periods of 1-2.5 years. These values were then compared with measurements made in six of the subjects during periods of microgravity on a KC-135 aircraft. The latency of the cortical potentials was also measured in the evening and in the morning before rising in a separate group of seven subjects, to determine whether there was any diurnal variation. RESULTS: The mean coefficient of variance of the latency of the SSEP was approximately 1.5% of the latency, and there were no changes in the latency over the period studied. There was no evidence of diurnal variation in the latency of the cortical SSEP. Satisfactory recordings of the SSEP were obtained in five of six subjects tested in microgravity. In three of these five subjects there was a significant decrease in the latency of the cortical SSEP in microgravity. CONCLUSIONS: In individual subjects the latency of the cortical SSEP varies within very small limits (1.5%) over 1-2.5 years. The results demonstrate the feasibility of recording SSEP's in the microgravity state. They show that relatively small changes (2-3 ms) in the latency of the SSEP can be detected when prior baseline values are established for each subject. The reason for the decrease in latency of the cortical SSEP in some subjects on the KC-135 is not known.

Adult↗
PubMedDate not supplied

[Basic purposes and results of a radiobiological experiment on the "Kosmos-690" biosatellite].

In 1974 the USSR carried out a rat experiment aboard the biosatellite Cosmos-690 equipped with a gamma-emitter. On the 10th flight day rats were irradied with doses of 220 and 800 rad. During the subsequent 10 days radiation damage developed. Similar experiments simulating the flight profile, except for weightlessness, were conducted on the Earth. The resulting data were compared. It is concluded that a short-term (up to 20 days) flight did not modify essentially the radiobiological effect.

Animals↗
PubMed2005

Assessment of simulated surgical skills in parabolic microgravity.

BACKGROUND: During spaceflight crew health is paramount in the success of flight missions. The delivery of healthcare during flight requires crew readiness for medical and surgical response. METHODS: There were 20 participants who were evaluated for accurate performance of 4 basic laparoscopic surgical skills (clip applying, cutting, grasping, and suturing) during parabolic weightlessness using an inanimate workstation aboard the NASA KC-135 aircraft. RESULTS: Data indicate that motor skill performance decreased within the parabolic microgravity flight environment. Performance in parabolic microgravity flight included futile effort with an increase in number of tasks attempted and a decrease in tasks completed successfully. CONCLUSIONS: There is a decreased frequency of accurate task completion in parabolic microgravity flight, but it is not an obstacle to implementation of effective training for providing in-flight medical care. The data reveal that individuals perform basic laparoscopic surgical simulation with greater effort in microgravity following simulation training.

Aerospace Medicine↗
PubMed1965

On the biological role of gravity.

The paper is dedicated to the memory of Galileo Galilei whose work is a great contribution to the development of a new branch of science--gravitation biology. Penetration of man into outer space necessitates a study of the role of gravity in the onto- and phylogenetic development of living organisms. This allows one to get insight into the biological action of weightlessness under the conditions of long-term space flight. The paper summarizes some results of the investigation of weightlessness effects in experiments on animals and during flights of Soviet and American astronauts. The rearing of animals in a special centrifuge under the conditions of prolonged action of accelerations simulating an increased gravity affects noticeably the formation of vegetative (height, weight, metabolism) and animal (vestibulo-tonic reflexes) functions as well as reactivity of the organism. Experiments employing the rearing of animals in a centrifuge represent one of the most promising methods of studying the urgent problem--biological action of increased and decreased gravitation conditions.

Acceleration↗
PubMed1979

A review of the consequences of fluid and electrolyte shifts in weightlessness.

This review describes the renal-endocrine mechanisms related to the early losses of fluid-electrolytes from the body during weightlessness as well as their contribution to longer term adaptation of fluid-electrolyte balance. The hypotheses presented were generated by a systematic analysis of body fluid and renal dynamics observed under conditions of actual and simulated spaceflight. These have increased our understanding of the effects of acute headward fluid shifts on renal excretion, the factors promoting excess sodium excretion and the regulation of extracellular fluid composition.

Adaptation, Physiological↗
PubMed1994

A comprehensive Guyton model analysis of physiologic responses to preadapting the blood volume as a countermeasure to fluid shifts.

The Guyton model of fluid, electrolyte, and circulatory regulation is an extensive mathematical model capable of simulating a variety of experimental conditions. It has been modified for use at NASA to simulate head-down tilt, a frequently used analog of weightlessness. Weightlessness causes a headward shift of body fluids that is believed to expand central blood volume, triggering a series of physiologic responses resulting in large losses of body fluids. We used the modified Guyton model to test the hypothesis that preadaptation of the blood volume before weightless exposure could counteract the central volume expansion caused by fluid shifts, and thereby attenuate the circulatory and renal responses that result in body fluid losses. Simulation results show that circulatory preadaptation, by a procedure resembling blood donation immediately before head-down bedrest, is effective in damping the physiologic responses to fluid shifts and reducing body fluid losses. After 10 hours of head-down tilt, preadaptation also produces higher blood volume, extracellular volume, and total body water for 20 to 30 days of bedrest, compared with non-preadapted control. These results indicate that circulatory preadaptation before current Space Shuttle missions may be beneficial for the maintenance of reentry and postflight orthostatic tolerance in astronauts. This paper presents a comprehensive examination of the simulation results pertaining to changes in relevant physiologic variables produced by blood volume reduction before a prolonged head-down tilt. The objectives were to study and develop the countermeasure theoretically, to aid in planning experimental studies of the countermeasure, and to identify potentially disadvantageous physiologic responses that may be caused by the countermeasure.

Adaptation, Physiological↗