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PubMedDate not supplied

Long-term operation of "Orlan" space suits in the "Mir" orbiting station: experience obtained and its application.

The started assembly of the International Space Station (ISS) and its further operation will call for a great number of extravehicular activity sorties (EVA) to be performed by ISS crews. Therefore, of great importance is to make use of the EVA experience gained by cosmonauts in the process of 15-year operation of the Mir orbiting station (OS). Over the 15-year period, Mir crewmembers wearing Orlan type semi-rigid space suits have accumulated 158 man/sorties from the orbiting station. Crewmembers used 15 suits in orbit and some of the suits were in operation for more than 3 years. The paper presents principal design features, which provide effective and safe operation of orbit-based suits, and briefly describes procedures for preparation and maintenance of suit systems, which ensure long-term operation of space suit in orbit. The paper gives results of the space suit modifications, presents suit performance characteristics and lists novel or upgraded components of the space suit and its systems. The paper also summarizes improvements in the Orlan type suits described in some earlier publications. They refer, in the first run, to the improvement of space suit operations characteristics and reliability, and the utilization of the Orlan type space suit in the ISS program. The paper analyses the experience gained and drawbacks detected and observations made, and gives statistical data on long-term space suit operations aboard the Mir station. The paper reviews certain problems in the process of EVAs performed from the station, and describes the ways of their solution as applied to the further utilization of the suit within the ISS program.

Astronauts↗
PubMed1991

The Space Station Freedom Flight Telerobotic Servicer: the design and evolution of a dexterous space robot.

The Flight Telerobotic Servicer (FTS) Project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station) Freedom (SSF). The FTS will provide a telerobotic capability to the Freedom Station in the early assembly phases of the program and will be employed for assembly, maintenance, and inspection applications throughout the lifetime of the space station. Appropriately configured elements of the FTS will also be employed for robotic manipulation in remote satellite servicing applications and possibly the Lunar/Mars Program. In mid-1989, the FTS entered the flight system design and implementation phase (Phase C/D) of development with the signing of the FTS prime contract with Martin Marietta Astronautics Group in Denver, Colorado. The basic FTS design is now established and can be reported on in some detail. This paper will describe the FTS flight system design and the rationale for the specific design approaches and component selections. The current state of space technology and the nature of the FTS task dictate that the FTS be designed with sophisticated teleoperation capabilities for its initial primary operating mode. However, there are technologies, such as advanced computer vision and autonomous planning techniques currently in research and advanced development phases which would greatly enhance the FTS capabilities to perform autonomously in less structured work environments. Therefore, a specific requirement on the initial FTS design is that it has the capability to evolve as new technology becomes available. This paper will describe the FTS design approach for evolution to more autonomous capabilities. Some specific task applications of the FTS and partial automation approaches of these tasks will also be discussed in this paper.

Biomechanical Phenomena↗
PubMed2002

The effect of simulated weightlessness on hypobaric decompression sickness.

BACKGROUND: A discrepancy exists between the incidence of ground-based decompression sickness (DCS) during simulated extravehicular activity (EVA) at hypobaric space suit pressure (20-40%) and crewmember reports during actual EVA (zero reports). This could be due to the effect of gravity during ground-based DCS studies. HYPOTHESIS: At EVA suit pressures of 29.6 kPa (4.3 psia), there is no difference in the incidence of hypobaric DCS between a control group and group exposed to simulated weightlessness (supine body position). METHODS: Male subjects were exposed to a hypobaric pressure of 29.6 kPa (4.3 psi) for up to 4 h. The control group (n = 26) pre-oxygenated for 60 min (first 10 min exercising) before hypobaric exposure and walking around in the altitude chamber. The test group (n = 39) remained supine for a 3 h prior to and during the 60-min pre-oxygenation (also including exercise) and at hypobaric pressure. DCS symptoms and venous gas emboli (VGE) at hypobaric pressure were registered. RESULTS: DCS occurred in 42% in the control and in 44% in simulated weightlessness group (n.s.). The mean time for DCS to develop was 112 min (SD +/- 61) and 123 min (+/- 67), respectively. VGE occurred in 81% of the control group subjects and in 51% of the simulated weightlessness subjects (p = 0.02), while severe VGE occurred in 58% and 33%, respectively (p = 0.08). VGE started after 113 min (+/- 43) in the control and after 76 min (+/- 64) in the simulated weightlessness group. CONCLUSIONS: No difference in incidence of DCS was shown between control and simulated weightlessness conditions. VGE occurred more frequently during the control condition with bubble-releasing arm and leg movements.

Adolescent↗
PubMed1995

The feasibility of Doppler monitoring during EVA.

During extravehicular activities (EVA) outside the spacecraft, astronauts have to work under reduced pressure in a space suit. This pressure reduction induces the risk of decompression sickness (DCS) by the formation of gas bubbles from excess nitrogen dissolved in the organism by breathing air at normal pressure. Under laboratory conditions the gas bubbles moving in the blood stream can be detected by the non-invasive ultrasonic Doppler method. By early detection of excessive bubble formation the development of DCS symptoms may be prevented by early application of preventative measures. The method could also be useful when applied in the space suit in order to compare the results of laboratory tests with operational results, because there is a discrepancy according to the DCS risk of laboratory experiments and actual EVA missions, where no symptoms have been reported yet. A prototype Doppler sensor has been developed and implemented in the Russian Orlan suit. To investigate the feasibility of this method under simulated space conditions, the equipment has been used in a series of 12 thermovacuum chamber tests with suited subjects, where intravenous bubble formation was compared to unsuited control experiments. In more than 50% of the suited tests good Doppler recordings could be achieved. In some cases with unsatisfying results the signal could be improved by breathholding. Although the results do not yet allow any conclusion about a possible difference between suited and unsuited subjects due to the small number of tests performed, the method proved its feasibility for use in EVA suits and should be further developed to enhance the safety of EVA procedures.

Aerospace Medicine↗
PubMed2000

The effect of staged decompression while breathing 100% oxygen on altitude decompression sickness.

INTRODUCTION: Space Shuttle extravehicular activity (EVA) requires decompression from sea level pressure (14.7 psia) to a 4.3 psia (30,300 ft) pressure suit. The transition currently involves altering the shuttle atmosphere to allow shirt-sleeve denitrogenation to occur during a 12 to 36-h staged decompression (SD) at 10.2 psia (9,800 ft) with an oxygen-enriched breathing gas (26.5% oxygen, 73.5% nitrogen). The denitrogenation provides protection from decompression sickness (DCS) during EVA in a 4.3 psia pressure suit. Our goal was to determine the highest altitude at which SD while breathing 100% oxygen (SD100) could provide effective protection from development of DCS symptoms after further decompression to 29,500 ft (4.5 psia). METHODS: There were 30 male subjects exposed to at least 6 of 11 conditions in random order on successive months to 29,500 ft for 4 h while performing mild exercise and being monitored for venous gas emboli (VGE) with an echo-imaging system. The subjects received 15 min of ground-level (GL) preoxygenation and an additional 60 or 120 min of SD100 at one of four altitudes between 8,000 ft (10.9 psia) and 18,000 ft (7.3 psia). Control exposures followed a 75- or 135-min ground-level preoxygenation. RESULTS: During SD100, one case of DCS occurred at 18,000 ft, but not at lower staging altitudes. Higher levels of VGE were observed during SD100 at 18,000 ft than during SD100 at any lower altitude. CONCLUSION: Staged decompression at 16,000 ft and below results in decompression risk during subsequent decompression to 29,500 ft similar to that following equivalent periods of ground-level preoxygenation.

Altitude Sickness↗
PubMed1994

Early stopping of aerospace medical trials: application of sequential principles.

A two-period, crossover trial was conducted in the hypobaric chamber on human subjects to compare the influence of inflight exercise (experimental) and restricted activity (control) on altitude decompression sickness (DCS) during simulated extravehicular activities. Out of 39 pairs (total of 78 exposures), 4 cases of DCS occurred under control and 5 occurred under experimental conditions. Analysis of the crossover results showed that the P values for differences in DCS occurrence was 0.56. Under these circumstances, it was necessary to decide whether additional information would be obtained by accruing more subjects. This problem was examined by using a skew sequential design in which the "stopping rule" was based on an alpha of 0.05 (one-sided) and power of 80%. The result of this analysis was in favor of the null hypothesis, and the trial was terminated. The authors recommend the use of similar stopping rules in aerospace trials to optimize sample size without compromising statistical validity.

Adult↗
PubMed1992

[Oxygen tension and water-soluble products of lipid peroxidation in blood of volunteers in hypobaric hyperoxia].

Oxygen tension in the arterial blood with transcutaneous method (tcPO2) and TBA-active products of venous blood plasma were measured during simulation of extravehicular activity. There was a parallel increase of tcPO2 and the level of TBA-active products upon introduction of hypobaric hyperoxia factor. Detrimental action of lipid peroxidation products on erythrocyte membranes can be one of the factors of anemia during space flight.

Adult↗
PubMed2005

Metabolic consequences of muscle disuse atrophy.

In response to decreased usage, skeletal muscle undergoes an adaptive reductive remodeling. This adaptive response has been found with disuse during human spaceflight, rat spaceflight, rat hind-limb unloading, bed rest, and aging. The reductive remodeling of skeletal muscle with disuse is largely independent of the reason for the disuse. The process involves more than a transition from slow to fast myosin fiber types. There are associated metabolic changes including a fuel shift toward glycolysis, decreased capacity for fat oxidation, and energy substrate accumulation in the atrophied muscles. Glycolysis is very effective for high-intensity short-duration acute activities, but if sustained output is needed, an energy profile where fat use is favored rather than compromised is desirable. For astronauts, there is a need to maintain as much functional capacity as possible during spaceflight for extravehicular activities. The shift toward increased activity of the glycolytic enzymes in atrophied muscle is accommodated by an increase in gluconeogenic capacity in the liver.

Animals↗
PubMed1988

Effects of exercise on the incidence of decompression sickness: a review of pertinent literature and current concepts.

The effects of exercise on the incidence of decompression sickness (DCS) are not completely understood. This paper reviews studies that have addressed this question. Studies have involved exposures of animals and human subjects to high pressures, which would occur in SCUBA diving operations, and to low pressures, which exist during high-altitude aircraft flights and extravehicular activities during space flight. The temporal course of the exercise in relation to the decompression procedure and the nature of the exercise may influence effects on DCS incidence. Effects of exercise on the uptake and elimination of nitrogen, the production of bubbles due to limb movements, the potential role of carbon dioxide, and current plans for further research are discussed.

Aerospace Medicine↗
PubMed1986

Blood biochemical factors in humans resistant and susceptible to formation of venous gas emboli during decompression.

Blood biochemical parameters were measured in 12 male human subjects before and after exposure to a staged decompression protocol, with simulated extravehicular activity, during 3 days. Following the exposure, significant changes occurred in several parameters, including increases in blood urea nitrogen, inorganic phosphate, potassium, and osmolality, and decreases in uric acid and creatinine. Pre-exposure blood samples from subjects who were susceptible to formation of venous gas emboli (VGE) during decompression exhibited significantly greater levels of total cholesterol, high density lipoprotein cholesterol, potassium, inorganic phosphate, calcium, and magnesium. The results indicate that, following this decompression profile, small but significant (P less than 0.05) changes occur in several blood biochemical parameters, and that levels of certain blood factors may be related to susceptibility to VGE formation during decompression.

Adult↗
PubMed1995

The experience in operation and improving the Orlan-type space suits.

Nowadays significant experience has been gained in Russia concerning extravehicular activity (EVA) with cosmonauts wearing a semi-rigid space suit of the "Orlan" type. The conditions for the cosmonauts' vital activities, the operational and ergonomic features of the space suit and its reliability are the most critical factors defining the efficiency of the scheduled operation to be performed by the astronaut and his safety. As the missions performed by the cosmonauts during EVA become more and more elaborate, the requirements for EVA space suits and their systems become more and more demanding, resulting in their consistent advancement. This paper provides certain results of the space suit's operation and analysis of its major problems as applied to the Salyut and MIR orbiting stations. The modification steps of the space suit in the course of operation (Orlan-D, Orlan-DM, Orlan-DMA) and its specific features are presented. The concept of the suited cosmonauts' safety is described as well as trends for future space suit improvements.

Equipment Design↗
PubMedDate not supplied

Accomplishments in bioastronautics research aboard International Space Station.

The tenth long-duration expedition crew is currently in residence aboard International Space Station (ISS), continuing a permanent human presence in space that began in October 2000. During that time, expedition crews have been operators and subjects for 18 Human Life Sciences investigations, to gain a better understanding of the effects of long-duration spaceflight on the crewmembers and of the environment in which they live. Investigations have been conducted to study: the radiation environment in the station as well as during extravehicular activity (EVA); bone demineralization and muscle deconditioning; changes in neuromuscular reflexes; muscle forces and postflight mobility; causes and possible treatment of postflight orthostatic intolerance; risk of developing kidney stones; changes in pulmonary function caused by long-duration flight as well as EVA; crew and crew-ground interactions; changes in immune function, and evaluation of imaging techniques. The experiment mix has included some conducted in flight aboard ISS as well as several which collected data only pre- and postflight. The conduct of these investigations has been facilitated by the Human Research Facility (HRF). HRF Rack 1 became the first research rack on ISS when it was installed in the US laboratory module Destiny in March 2001. The rack provides a core set of experiment hardware to support investigations, as well as power, data and commanding capability, and stowage. The second HRF rack, to complement the first with additional hardware and stowage capability, will be launched once Shuttle flights resume. Future years will see additional capability to conduct human research on ISS as International Partner modules and facility racks are added to ISS. Crew availability, both as a subject count and time, will remain a major challenge to maximizing the science return from the bioastronautics research program.

Aerospace Medicine↗
PubMed1999

Teaching of space life sciences.

Space life sciences is not really a new life sciences discipline such as immunology was some decades ago and it may never be so. Rather it is a field that will provide each existing life sciences discipline with new and more information gathered from space research. In fact, the danger is that space research will be confined in a separate discipline, and thus it will be cut off from classical ground research. Conversely, scientists should increasingly consider spaceflight as a tool and should integrate the findings of space research into their traditional disciplines. A brief survey of topics and main findings in the various subdisciplines of space life sciences is provided. This is followed by a discussion of typical problems encountered such as access to space, controls, ground-based simulations, medical care in space, extravehicular activity, and environmental control and life support. As many space life sciences courses are initiated around the world either by space agencies or universities or jointly, there is a need to consider the international, intercultural, and interdisciplinary aspects of such programs. It is argued that the growing knowledge derived from space research should be integrated into the regular teaching of life sciences rather than leaving it confined to a separate field. Teaching of space life sciences is a prime candidate for the application of the new techniques of "cyberspace education", where interactive learning and globalization of the learning process will take a leading place. The experts and student body are dispersed over many nations, research is of necessity conducted on a basis of international cooperation. The conduct of tele-education is discussed and existing information sources and courses are listed.

Biological Science Disciplines↗
PubMed1997

Medical monitoring in long-term space missions.

The following principles, derived from the experience of medical support during past spaceflights, can provide a basis for a system of health monitoring and diagnosis during long-term and interplanetary missions: a system of preflight medical screening; medical screening on a systemic basis, which may include purposeful diagnosis in subsystems following the method of hierarchic structure; use of an individual approach; correction of the medical program with respect to the space crew status; assessment of the interrelations of the entire complex of parameters; utilization of the methods of correlation, classification and identification to elicit interrelations between different functions; evaluation of shifts in body functions and their adequacy to ambient conditions; continuity of medical examinations during all pre-flight stages, during flight and after completion of flight; analysis of information and anamnestic data by means of data bases; confidentiality of medical conclusions. Discussed are a classification of unfavorable microgravity-related syndromes, possible impairments due to abnormal situations, and some approaches to the prediction of the risk of various diseases, in relation to the construction of a conceptual diagnostic model for interplanetary missions. In the interest of medical monitoring special significance is attributed to the knowledge of individual norms for each crew member and of his unique peculiarities. Such data can be compiled by means of statistical analysis (single and multidimensional analysis) of the results of medical examinations and of observations during selection, training and tests. Selection of necessary physiological parameters, functional loads and data processing techniques which can be used in combination with other data sources for inflight diagnosis should be based on the following principles: the use of informative, non-invasively registered parameters and functional tests to reveal adverse states or most probable diseases; the possibility to assess the dynamics of physiological parameters and the status of the regulatory systems, and to predict possible developments in the body; the possibility to check the efficiency of countermeasures; the possibility to differentiate a physiological state adapted to the current environment from a pathological state; the possibility to differentiate between specific and non-specific reactions; the possibility to differentiate defensive, adaptive or compensatory phenomena from pathological manifestations. This paper describes the application of single- and multidimensional, statistical methods to process diagnostic information, to reduce the vector dimension of the chosen parameters, and to classify and identify individual and crew physiological standards providing the ability to assign an individual to a suitable team. Thus it will be possible to acquire comprehensive and statistically reliable information in compact format, and thus to perform a more incisive analysis and diagnosis of various states by comparing them with the baseline preflight data. These theoretical considerations constitute the basis for a conceptual model for medical diagnosis in long-term orbital and interplanetary missions. The paper contains a section dealing with the practical aspects of medical monitoring and diagnostic examinations during Mir missions. The program of medical monitoring for long-term Mir missions incorporates on-line monitoring during intravehicular and extravehicular activities, routine daily examinations, periodic extensive medical examinations accomplished on schedule or an indication. The Mir program includes cardiovascular investigations at rest and during functional loading, testing of the cosmonaut muscular systems, validation of the standard training protocols, occasional blood and urine analysis, incl. serum immunoglobulins, and blood cell counts. (ABSTRACT TRUNCATED)

Animals↗
PubMed1987

Nutrition and metabolism in spaceflight.

The United States Space Station being planned for the 1990s will accommodate six or more crew members on 90-d flights in low earth orbit. Adequate nutrition will be essential for maintaining crew health, effectiveness and morale. Although much is known from prior space experience about in-flight metabolism, nutrition and associated food technology, important gaps in knowledge exist that need additional research, development and analysis to meet Space Station requirements. This paper is a synopsis of a report prepared by the Life Sciences Research Office (LSRO), FASEB, from a study of the nutritional and metabolic aspects of spaceflight. It reviews available data on the metabolic responses to spaceflight including extravehicular activity, physiological responses to microgravity that influence metabolism and energy needs, in-flight nutritional experience, space menus, food packaging, in-flight food service methodology, water supply and disposal of food wastes. The LSRO ad hoc Working Group identified critical gaps in knowledge and suggested corresponding research approaches for acquiring essential new data. The 38 research suggestions detailed in the report address in-flight metabolic needs, nutrient requirements, food systems and nutritional countermeasures.

Diet↗
PubMed2002

Investigation of radiation doses in open space using TLD detectors.

The low energy component of the cosmic radiation field is strongly modified by the shielding of the spacecraft and it is time and location dependent. Thermoluminescent lithium fluoride detectors have been applied to determine the radiation doses inside the ESA-Facility BIOPAN. The BIOPAN facility was mounted outside and launched on a Foton spacecraft and opened to space to allow exposure of several experiments to open space. Standard TLD-600. TLD-700 chips, two layers MTS-Ns sintered pellets with different effective thickness of the sensitive layer and MTS-N of different thickness have been exposed with different shielding thicknesses in front of them. The measured TL signal in the 0.1 mm thick detector just shielded by an aluminised Kapton foil of 25 microm thickness in front yielded a dose of 29.8 Gy (calibrated with 137Cs gamma rays) for an exposure time of 12.7 days: after 2.5 g.cm(-2) shielding the doses dropped to 3 mGy. The monitoring of radiation doses and its depth dose distribution outside the spacecraft are of great interest for radiation protection of astronauts working in open space. The knowledge of depth-dose distribution is a prerequisite to determine the organ doses an astronaut will receive during an extravehicular activity (EVA). The BIOPAN experiments are to be continued in the future.

Aerospace Medicine↗
PubMed2006

The MATROSHKA facility--dose determination during an EVA.

On 29 January 2004 the MATROSHKA facility was launched with a Russian Progress to the International Space Station. MATROSHKA is an ESA project, which has been achieved under the direction of the German Aerospace Center (DLR). The project is a cooperation of >16 research institutes from all over the world and is currently the biggest international experiment in radiation dosimetry ever performed in space. The facility simulates, as exact as possible, an astronaut during an extravehicular activity. It was successfully installed outside the Russian segment 'Zvezda' on 26 February 2004 and will remain there for a 1.5 year exposure period. The main task of the facility is to measure particle fluence and energy spectra, dose and dose rates outside and inside--including organ dose determination--in an anthropomorphic phantom mounted on the outside of the Space Station with passive and active dosemeter systems.

Body Burden↗
PubMed2001

Model of human/liquid cooling garment interaction for space suit automatic thermal control.

The Wissler human thermoregulation model was augmented to incorporate simulation of a space suit thermal control system that includes interaction with a liquid cooled garment (LCG) and ventilation gas flow through the suit. The model was utilized in the design process of an automatic controller intended to maintain thermal neutrality of an exercising subject wearing a liquid cooling garment. An experimental apparatus was designed and built to test the efficacy of specific physiological state measurements to provide feedback data for input to the automatic control algorithm. Control of the coolant inlet temperature to the LCG was based on evaluation of transient physiological parameters that describe the thermal state of the subject, including metabolic rate, skin temperatures, and core temperature. Experimental evaluation of the control algorithm function was accomplished in an environmental chamber under conditions that simulated the thermal environment of a space suit and transient metabolic work loads typical of astronaut extravehicular activity (EVA). The model was also applied to analyze experiments to evaluate performance of the automatic control system in maintaining thermal comfort during extensive transient metabolic profiles for a range of environmental temperatures. Finally, the model was used to predict the efficacy of the LCG thermal controller for providing thermal comfort for a variety of regiments that may be encountered in future space missions. Simulations with the Wissler model accurately predicted the thermal interaction between the subject and LCG for a wide range of metabolic profiles and environmental conditions and matched the function of the automatic temperature controller for inlet cooling water to the LCG.

Algorithms↗