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This paper considers to physiological effects of microgravity affecting different organs systems such as cardiovascular, neurohumoral, immune, and musculoskeletal systems. These physiologic changes suggest adverse influence with pathological processes during space flight and associated with high risk of morbidity of cosmonauts.

This paper shows that the method of water and air purification using immobilized cells and enzymes can be applied in regenerative life support systems in a habitable enclosed environment. This method is based on selective and adaptive functions of enzymic systems of microorganisms to assimilate organic components of the medium to be eliminated. Advantages of biocatalysis are low energy requirements and mild temperatures of purification leading to practically complete elimination of the substrate. Due to immobilization, cells and enzymes constitute an independent component which can be added to any continuously operating system of purification without generating a specific interface which is crucially important in microgravity. This allows the process of purification to be controllable. The resulting water and air meet biological requirements because they are formed under the influence of living organisms as in natural biogeocenoses. The production of ecologically pure water and air is highly important for long-duration space missions, especially for flights to Mars.

Prediction of mental performance is one of the major goals of space psychophysiology. This paper discusses experimental data about mental performance of the cosmonauts A. Alexandrov, A. Momanda, V. Savinykh and V. Polyakov as predicted by means of a Soviet-Bulgarian psychodiagnostic unit Pleven-87. The investigations were performed within the framework of the Prognosis experiment on Mir. The experimental results demonstrated that the psychodiagnostic unit Pleven-87 provided reliable predictions, using adequate and sensitive methods. This unit can find application in mental performance evaluation and prediction.

This paper present hematological data obtained during space flights of the third and the fourth prime crew flights (EO-3 and EO-4). In the EO-3 flight, RBCs, WBCs and blood formed elements were counted by the cosmonaut-researcher. In the EO-4 flight, blood was drawn by the cosmonaut-researcher and analyzed on the ground; also, blood smears treated in the Microview unit and videotaped were used. Blood parameters in EO-3 and EO-4 crewmembers were close or equal to the normal. However there were cases with changes in bends, myelocytes, neutrophils, lymphocytes; also anisocytosis, hypochromia, target-like erythrocytes, and single acanthocytes were seen. Comparison of blood smears on unstained and stained glass slides revealed significant differences in the amount of target-like erythrocytes in the same cosmonaut at the same time (on the prestained glass slide only 4 erythrocytes and no aggregates in single fields of vision were detected while on the unstained glass slide aggregates in single fields of vision were seen). Pre- and postflight examinations of bone marrow revealed polymorphocellular marrow and mature hemopoietic cells.

This paper presents the method, algorithm and results of structural identification as a model of pilot's perception of perturbed angular motion of the cockpit and its transmission to the joystick as well as spectral density of the remnant corresponding to the transmission process. Assessments of scalar quasilinear and (more effective) multichannel models of pilot's functions are given. The assessments have been obtained for a single operator. They illustrate the potentials of this procedure.

This paper presents the results of evaluating blood morphology (counts of red blood cells, hemoglobin, reticulocytes, platelets, leukocytes and their forms), hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin content and concentration, and erythrocyte sedimentation rate (ESR) in 9 test subjects during a 370-day head-down tilt study. It was demonstrated that blood morphology variations in 9 test subjects remained within normal variations throughout the entire period of observation, including the baseline, head-down tilt, and rehabilitation periods. There were the following exceptions. In the baseline period, a single episode of MCV increase and MCH decrease was recorded. In the course of head-down tilt, monocytosis, lymphocytosis, thrombocytopenia, basophilia, and lowered MCH were occasionally observed. MCV was slightly increased during several measurements. As compared to the norm, hematocrit increased or decreased. After exposure, there was a single episode of a decrease of erythrocyte count and hemoglobin, hematocrit, an increase of MCV and basophil count, and three episodes of monocytosis. These blood changes during 370-day head-down tilt should be viewed as a result of a combined effect of adverse factors accompanying hypokinesia, particularly reduced infection resistance.

This paper presents observations over 18 cosmonauts who participated in space flights of 75 days to 12 months and stayed in a sanatorium in the city of Kislovodsk thereafter. The rehabilitation stage continued for 30-40 days. The early stage of rehabilitation lasted 2-3 weeks at the cosmodrome or Gagarin Cosmonaut Training Center. They were taken to a sanatorium for further medical rehabilitation when they showed residual phenomena of postflight fatigue, incomplete recovery of the cardiovascular and musculoskeletal systems, hematological, biochemical and immunological changes. Rehabilitation measures included physical training, terrain cure, balneological procedures. Medical monitoring was performed using physical examinations, arterial pressure and heart rate measurement, ECG, Holter monitoring during terrain cure, and blood and urine clinical analysis. The results showed a beneficial development of readaptation, increase of functional capabilities and physical work capacity of crewmembers. Final physical examinations gave evidence that most physiological parameters returned to the preflight level. Increase of flight duration to 11-12 months did not cause increase of post-recovery duration.

This paper presents the results of pre- and post-flight vestibular examinations using single and combined vestibular, optokinetic, proprioceptive, postural tests and cerebellar coordination tests. After extended flights most crewmembers showed spontaneous, position and positional nystagmus that points to vestibular dysfunction. The methods developed by the authors helped differentiate mechanisms of post-flight vestibular dysfunctions: in Group 1 subjects spontaneous nystagmus parameters varied during all tests; in Group 2 subjects they varied only in response to active tilt tests; in Group 3 subjects they varied only in response to vestibular, optovestibular and proprioceptive stimulation; and in Group 4 subjects they varied only in response to proprioceptive optovestibular stimulation and cerebellar coordination tests. Individual patterns of the above changes are associated with different pathways of adaptation of the vestibular function that depend on the involvement of various structures and compartments of the central nervous system.

This paper discusses current problems of psychophysiological support of manned space missions and presents the concept of a psychophysiological complex of the orbital biomedical laboratory Medilab and other advanced space vehicles based on new methodological approaches. The paper describes principles of selection of psychophysiological methods to be used in Medilab programs as well as their instrumental, mathematical, hardware and software structures.

This paper presents the data about red blood cell metabolism and the structure and function of erythrocyte membranes obtained from two cosmonauts after their 326- and 160-day flights. In both cases we observed inhibition of energy formation (decrease of the rate of glycolysis and ATP content) and enhancement of oxidative processes (decrease of reduced glutathione and activity of antioxidative enzymes). The above changes in the metabolic status of erythrocytes are correlated with shifts at the membrane level, particularly with variations of membrane lipids, phospholipid spectrum and ratios of phospholipid fractions, alteration of membrane-bound enzymes (ATPase) and increase of cell resistance to acid hemolysis. The changes in the erythrocyte membrane leading to lower cell deformability and possible shifts of blood rheological properties give evidence that it is necessary to use preventive membrane stabilization measures at certain flight stages and during readaptation.

This paper presents results of studying spontaneous and evoked optokinetic, opto-oculomotor and vestibulo-oculomotor reactions in microgravity. The examinations were performed during the 7-day Soviet-Indian and 237-day Salyut-7 missions. During an early stage of adaptation to microgravity the following changes occurred: enhanced spontaneous activity of the eyes, including spontaneous nystagmus in one of the crewmembers, decline of the efficiency of saccadic pursuit (disappearance of saccades in the course of pursuit of a moving stimulus, decrease of the saccadic amplitude, emergence of correction microsaccades in response to fixation events), and decrease of the threshold of the optokinetic nystagmus. The compensatory counter-rotation of the eyeballs during head side-to-side movements with open eyes in dark glasses did not disappear but slightly decreased, being slightly accompanied by low-amplitude nystagmus. When rocking the head with open eyes, one of the cosmonauts showed a complete eye destabilization and other cosmonauts displayed high-amplitude nystagmus. In response to head rotation with open eyes they developed clonic nystagmus. Vestibular stimulation in the form of active head movements helped to normalize the pattern of opto-ocular responses.

This paper discusses changes in the psychic functions of an operator working in the interactive mode under the influence of adverse environmental effects that cannot be modified. It is postulated that in this situation the strategy of solving operational problems may transform due to changes in the structure of decision taking. The paper describes simulation of operator's activities involved in controlling information flows in a stressful environment of two degrees of complexity.The investigations demonstrated a trend for a decline of operator's work capacity, helped develop mathematical models to predict performance variations in an extreme environment, as well as formulate recommendations as to how computer-interaction efficiency can be increased.

This paper discusses the functional characteristics of the man-plant-mineralization system and the environment it forms when it is supplemented with a photoautotrophic component including higher plants and algae. The functional characteristics of the higher plant component were studied when it operated first in an independent cultivation mode, then coupled with a biological system of human and biocomplex waste mineralization, and finally with a human gas exchange system and Chlorella containing photosynthetic reactors. This approach demonstrated for the first time that Chlorella and higher plants can normally work in a common autosphere. The paper also presents quantitative data about the use of higher plants in a biological life support system. Data analysis shows that the total plant yield did not diminish when the system was closed and man, mineralization system and algal reactors were connected. However although the total photosynthetic productivity remained unchanged, the yield of useful crops decreased. This points to a complex nature of the above effects, the causes of which remain so far inexplicable and require further study.

This paper presents the results of examinations of 19 cosmonauts, 12 of whom made 7-day flights and 7 took part in space flights of 150, 211 or 237 days. In plasma, parathyrin, calcitonin and gastrin concentrations were measured. A complex mosaic of hormonal regulation of bone metabolism reflects multifactorial and flexible patterns of calcium homeostasis, with individual variations included. It is probable that the specific weight of different components of the system maintaining calcium homeostasis varies depending on the exposure time and activity of related regulatory systems.

This paper discusses general concepts and specific details of the habitability of space stations and planetary bases completely isolated from the Earth for long periods of time. It emphasizes inadequacy of the present-day knowledge about natural conditions that provide a biologically acceptable environment on the Earth as well as lack of information about life support systems as a source of consumables (oxygen, water, food) and a tool for waste management. The habitability of advanced space vehicles is closely related to closed bioregenerative systems used as life support systems.

This paper presents medical results obtained in a Salyut-7 8-month manned mission in which a physician-cosmonaut took part. The results include body mass and height measurements, vestibular studies, cardiovascular studies at rest and in response to staged functional loads (with echocardiographic examinations accentuated), metabolic and hormonal studies. The paper also gives information about medical aspects of extravehicular activities. It is emphasized that during the mission both old and new methods of research were used and medical results of preceding flights were considered.

The paper presents data concerning the amino acid pool of rats flown on board Cosmos-1129 and exposed to the ground-based synchronous experiment. Certain changes in the amino acid pool of flight and synchronous rats have been found. The changes seem to be associated with the selective rate of incorporation of free amino acids into the biosynthetic processes during acute adaptation and with alterations in the protein synthesis rate.

This paper summarizes the data on external respiration and energy expenditures of men exposed to zero-g for 185 days and to 1/6 g on the lunar surface reported by Soviet and foreign authors. The paper also discusses factors that may be responsible for a higher level of gas exchange processes at reduced g.

The paper describes the effect of exercises, LBNP, controlled water and salt consumption, and drugs used as countermeasures against cardiovascular deconditioning during prolonged (2--7 weeks) head-down bed rest. Each of the above countermeasures applied separately had a limited effect. The use of a combination of exercises, LBNP and water-salt supplements at the final stage of the bed rest experiment made it possible to prevent entirely deterioration of work capacity and decrease of orthostatic tolerance of the test subject. The paper presents the scheme and regimens of the above countermeasures employed to meet the requirements of the flights of the orbital station "Salyut".

The paper presents body mass and leg volume measurements of 21 prime crewmembers of Salyut-6 and Salyut-7 flights. It was found that body mass variations were different in sign. In most crewmembers body mass decreased by 1.2-2.0 to 6.0 kg. In some crewmembers this parameter increased by 1.0 to 4.5 kg during the entire flight or at certain flight stages. This observation confirms the concept that metabolism produces an important effect on body mass variations. It also points out that the space diets used are adequate to metabolic requirements. Leg volume of all cosmonauts decreased in the following manner: the decrease was the greatest during the first flight day, slightly less during the first flight month and still less during the subsequent 2 or 3 months of flight. Exercises that were performed at a larger workload, especially during the second half of flight, seemed to help stabilize or occasionally increase leg volume.

The paper discusses certain aspects of interaction between aviation and space medicine, contribution of aviation medicine into the development of space biology and medicine, and the role of cosmonautics in current achievements of aviation medicine. The paper describes advances in studies of space flight effects, development of life support and flight safety systems, medical and psychological support of the flight personnel, implementation of new methods and techniques, electronics, computers and automatics. Particular importance is attached to the rapid development of ergonomic approaches to the design and application of new technology, study of psychophysiology and psychology of human efficient activity in the system "man--flying vehicle--environment", i. e. psychophysiological ergonomics. Certain methodological and organizational aspects of the development of aviation and space medicine are briefly described.

The paper presents a mathematical model and differential equations to be used in computer-aided estimations of the positive pressure in human lugs upon space cabin blast decompression. The paper gives a simplified method of computing the pressure which utilizes a special diagram of decompression of a rigid container communicating with the cabin through a hole of a constant area. The characteristic feature of the method is a simultaneous computation of the air outflowing from the lungs and their expansion during decompression. The paper illustrates the advantage of the simultaneous computation of the processes and specifies the pulmonary regions of positive pressure at given blast decompressions. The paper compares theoretical and experimental (data by foreign researchers) peak values of the positive pressure in human lungs during blast decompression, indicating good agreement of the results.

The paper gives the results of physical examinations of P.I. Klimuk and V.I. Sevastyanov during their flight aboard the orbital station Salyut-4. The examinations were carried out by means of the Polynomial-2 device at rest and under the conditions approximating basal metabolism. Since the end of the first flight week the circulation parameters did not differ substantially from the preflight values. Stroke volume and cardiac output increased slightly. In weightlessness circulation parameters varied with respect to the work done by the cosmonauts. On the first postflight day peripheral resistance, arterial pressure and cardiac output were increased.

The paper discusses the possibility of repeated termination of plant vegetation by prolonged darkness approximating the lunar night. This may be helpful for the incorporation of higher plants into the life support system of lunar bases, the solar light being used for illumination. In this connection vegetables (beet Bordeaux, turnip Petrovskaya, carrot Chantanet, dill, radish Virovsky white) and wheat (variety Sonora) were cultivated during the lunar light-dark cycle (i. e. 15 day light: 15 day dark). The experiments demonstrated that traditional plant products can be obtained under the conditions of lunar photoperiod. Grain of wheat grown during the lunar photoperiod were tested as seed material for further cultivation under similar conditions.

This paper discusses theoretical foundations of biological life support systems (BLSS), major stages of their development and performance parameters of BLSS models developed by the Institute of Biomedical Problems during the past 25 years. Comparison of the size and structure of these models with the structure of natural ecosystems allows the conclusion that BLSS can be operational in an environment that does not differ drastically from natural biocenoses in terms of living matter and basic ingredients, i.e. oxygen, carbon dioxide, water.

The paper presents the results of the morphological examination of tests of the Wistar rats flown for 22 days onboard the biosatellite Cosmos-605. Histological, histochemical, electron microscopic and biometric investigations of sex glands carried out 24-48 hours and 26-27 days postflight show that an exposure of the rats to weightlessness and other space flight factors induced no morphological changes in the spermatogenic tissue or disorders in the spermatogenic process of the rats. The offspring of male rats that were exposed to 22-day weightlessness did not differ from the controls with respect to the number of the newborns, their weight at birth, weight gain during the first postnatal month, resistance to hypoxia, etc.

This review of radiation protection in space flight considers specific features of radiation effects (the composition of radiation, space-time changes of fluxes of charged particles, nonuniform radiation fields in spacecraft modules, formation of secondary radiations, etc) and the major sources of radiation hazards in space (Earth radiation belts, solar and galactic cosmic radiations). The paper presents estimates of the equivalent dose of protons and electrons of the Earth radiation belts at various orbits, as well as radiation characteristics of certain proton solar flares and galactic cosmic radiation. The paper also discusses the present-day criteria of radiation safety used in calculations of the shielding of manned spacecraft. The paper gives the standards of allowable radiation levels used in the USSR.

The paper discusses the man's contribution to the formation of aerosol particles in manned enclosures. The data obtained in prolonged simulation studies suggest that man is the major source of aerosol contamination. The aerosol concentration and disperse composition are found to depend on the free volume per man. The paper presents for the first time the data on the rate of dust formation in manned enclosures.

This paper considers the possibility of characterizing space flight radiation safety, using a value which is integrated over the flight time, takes into account the radiation processes in an irradiated body and averages the probability of adverse radiobiological effects with respect to the distribution of solar proton flares of varying intensity. The proposed characteristic is compared with the current standards with reference to a hypothetic interplanetary flight.

This paper reviews existing data on bone marrow partial shielding in animal studies with reference to partial-body protection in space radiobiology and medicine. Analysis of reported data indicates the efficacy of the method to protect animals (including dogs) exposed to gamma-radiation and high-energy protons. Experimental findings that demonstrate the effectiveness of bone marrow partial shielding show that this method may be used for partial-body protection in space flight.

The paper describes a model of an experimental ecological system consisting of autotrophic and heterotrophic components and a nutrient medium. The system has a zero stationary state and needs a correction. The life time of the system and the level of the necessary correction have been determined for the experimental ecological system: lettuce - slugs - nutrient solution. Optimal conditions for the conjugation of trophic components of the system have been established.

This paper presents the results of examinations of 19 test subjects exposed to head-down tilting at -8 and -15 degrees and of 14 test subjects kept in water immersion for 24 hours. During the first hours of exposure the renal excretion of water and monovalent ions increased. Renin and aldosterone measurements showed that changes in the sodium and potassium excretion were produced by a lower activity of the renin-angiotensin-aldosterone system in the first 1.5 hour of hypokinesia. During immersion the renal excretion of calcium and magnesium also grew, especially in the evening and at night. The PTH production and calcium concentration in blood increased, thus augmenting the nephron load. The diurnal rhythms of the renal excretion of potassium, calcium and magnesium remained unchanged and those of water, osmotically active substances and sodium varied. The data obtained indicate significant changes in water-salt metabolism and its regulation within the first hours of head-down tilt and water immersion.

The paper discusses the results of five studies on 35 test subjects conducted to test diets of dehydrated products to be used in prolonged space flights. The studies have demonstrated that a diet consisting of only dehydrated food products can be used for a prolonged time (up to 1 year). Dehydrated foods after a 2-year storage and proton irradiation at a dose of 24,000 rad retain their biological value and assure an adequate nutritional status. On this basis a space diet composed of dehydrated foods has been developed.

The major parameters of the mineral component and protein matrix of bones were investigated in 30 rats flown onboard Cosmos-1129. Postflight, the content of calcium decreased by 7.8%, that of phosphorus diminished by 11.8%, the Ca/P ratio increased by 5.9%, the content of collagen diminished by 14.7% and that of non-collagenous proteins by 45.7% and the content of sialic and hexuronic acids increased by 36.2% and 14.6%, respectively, as compared to the vivarium controls. The paper discusses the role of EDTA-and HCl-protein extracts, soluble and poorly soluble calcium fractions, protein-Ca-phosphate complex, sialic and hexuronic acids in the mechanism of calcium binding by the bone organic matrix.

The paper describes the radiation environment in the compartments of the orbital station Salyut-4 and in its flight orbit. It also discusses the measures taken to provide radiation safety of the crewmembers and the main results of radiation monitoring. During the flight the dose received by the crew was 1400 mrem.

The paper presents the results of an exposure of cells of the Syrian hamster strain VNK-21 to space flight effects. In contrast to the cell culture kept in a thermostat at 29 degrees C, the cell culture that was maintained in thermally uncontrolled conditions developed noticeable structural and physiological changes induced by suboptimal temperatures. It was concluded that a 6-day exposure to weightlessness exerted no adverse effect on mammalian cells in vitro and produced no stable structural or physiological changes. Some changes that were detected in the cell culture--faster ageing, stable tendency to an increase of the number of cells with enlarged nuclei, an increase of the mitotic index at an early stage of cultivation--need further investigation.

The effect of a 22-day space flight on lymph organs of rats was studied. The exposure produced hypoplasia of lymph organs and reduced the weight of the spleen and the thymus to the greatest extent. It was shown histologically, morphometrically and cytologically that hypoplasia of the spleen was associated with the decreased number of lymphocytes and erythrocytes whereas hypoplasia of the thymus and lymph nodes was related to the diminished number of lymphocytes. Changes in the lymph organs of flight rats were reversible. The structure of lymph organs restored by the 27th postflight day. The paper discussed pathogenetic mechanisms of the changes in the lymph organs of rats due to space flight effects and compares the data with the postflight medical examination of cosmonauts.

This paper presents physiological and hygienic evaluations of the food supply of Salyut-7 crews in normal conditions, simulation and actual flights of various duration (211, 150, 237, 165 and 126 days). The examinations have shown that the diets used have provided satisfactory health conditions and good nutritional status of the crewmembers.

This paper presents pooled data about the factors determining health status and work capacity of aircrew using positive pressure breathing systems at altitudes over 12,000 m. It is indicated that the system compensating positive pressure is primarily responsible for the protective and ergonomic characteristics of altitude equipment.

This paper is the first summary of regular electrocardiographic examinations of 21 cosmonauts who made 42 space flights during the years 1964 through 1985. Electrocardiographic examinations were performed before, during and after flight. The most common ECG abnormality recorded was extrasystolic arrhythmia that occurred very frequently during provocative tests. In long-term flights changes in the phase of ventricular repolarization were predominant due to the effects of microgravity and other fright factors. The ECG changes were transient and of insignificant prognostic value. Long after return to the Earth three cosmonauts developed ECG changes typical of myocardial infarction, hypertension or hypertension combined with latent ischemic heart disease. It is maintained that these pathologies were not caused by the exposure to space flight effects.

The paper presents general principles underlying the construction of mathematical systems used to predict the human health status in space flight. It describes methods of prediction based on the concepts of homeostasis and general adaptation syndrome. The paper discusses applications of methods of statistic approximation and expertise estimates to predict changes in different parameters of the Salyut crewmembers. It gives an evaluation of the accuracy with which variations in the heart rate of the Salyut crewmembers were predicted using a linear model and expertise estimates.

In the course of the space era the duration of manned flights increased from 108 minutes to 326 days. During the flights a large number of biomedical investigations were carried out to study the phenomenology and mechanisms of space flight effects on the human body. It was demonstrated that exposure to microgravity produced most significant changes. Short-term effects include space adaptation syndrome changes associated with fluid shifts and changes in movement coordination. Long-term effects involve various changes in the musculoskeletal system, cardiovascular system, metabolism and its regulation, endocrine system, blood and immunity system. This paper describes symptom-complexes that are consistently observed in space flight, discusses mechanisms of changes and adaptation of vital physiological systems, and outlines main periods of changes during and after flight.

The paper describes the design and experimental conditions of rat irradiation aboard the biosatellite Cosmos-690. An essential dose gradient due to different distances between the gamma-source and irradiated rats as well as due to the presence of construction components and equipment in the beam was made up by a special dose-equilibrating filter. The spectral distribution of scattered radiation reached maximum in the region of 0.1--0.3 Mev. The average dosage in the location of the main group of animals was 800 +/- 85 rad and that in the location of an additional group was 220 +/- 25 rad.

The paper presents the results of examinations of solar cosmic rays recorded during 1969--1978 by Meteor satellites in the high latitude areas of the Earth magnetosphere. The purpose of the investigations is to develop methods for diagnosing and predicting the radiation environment in the near-Earth space. Morphological features of proton events, and their relationship with the characteristics of the source and the flare, the state of the interplanetary space and the magnetosphere are described.

At the final stage of long-term space flights first aid should be rendered in a specific way in cases of critical situations. Resuscitation and anesthesiology measures should be applied, if necessary, after study of flight-induced changes in the vital organs and systems. The paper describes the most important factors that should determine the tactics of resuscitation-anesthesiology support of the immediate postflight stage, if theoretically feasible acute life-endangering states develop. It also presents substantiated correction of routine clinical protocols of resuscitation aid.

Major problems of biorhythm are discussed. Among the numerous and diverse rhythms inherent in the human body (which is the subject matter of the present paper) circadian (essentially 24-hour) variations play the leading role. This kind of rhythm is of universal and mandatory character which makes it possible to categorize it as a law. The system of circadian rhythms incorporates elements of both synchronization and desynchronization. In the welfare state synchronization elements are prevailing while in space flight the specific weight of desynchronization increases due to the permanent desynchronization factor--weightlessness. Due to this, crewmembers are to adhere strictly to the work-sleep regimen.

This paper briefly describes physiologo-hygienic evaluations of space suits, data of the preflight training and extravehicular activities of the Salyut-6 crewmembers. It discusses changes in physiological parameters, energy expenditures, heat release and associated performance of the autonomic life support system. The paper also analyzes physiologo-hygienic aspects of the extravehicular activity of the Salyut-6 crewmembers.

This paper discusses regional hemodynamics and vascular regulation during and after space flights of over 3 months in duration. Mechanisms of cardiovascular adaptation to weightlessness are described. The postflight differences in the recovery of regional hemodynamics seem to depend on the individual characteristics, age-related changes of the cardiovascular system, as well as the countermeasures and rehabilitation measures performed during and after flight.

This paper reviews the basic stages in the development of radiation safety of space flights within the framework of the Intercosmos program, including ground-based experiments on charged particle accelerators and gamma-emitters and actual flight studies onboard biosatellites and orbital stations. The paper also discusses norms and standards of radiation safety as related to flights of varying duration. It emphasizes the contribution made by Intercosmos cooperative projects into the development of space flight radiation safety parameters adopted as standards by the USSR Standardization Committee.

This paper presents the results of measuring single heavy ions (HI) of galactic cosmic rays during 40- to 457-day flights of manned orbital stations Salyut-6 and Salyut-7. Cytogenetic analysis of Lactuca sativa seeds showed a significant increase of aberrant cells and cells with multiple chromosome aberrations in seeds hit with HI compared to non-hit++ seeds during flights of 123 to 457 days in duration. There was a good correlation between curves showing aberrant cells as a function of flight of the dose absorbed, viz. 16.0 to 63.4 mGy. These findings suggest a high biological effectiveness of heavy ions of galactic cosmic rays.