Preliminary results of medical investigations during manned flights of the Salyut 4 orbital station

In 1975 the Soviet Union performed two manned flights on board the orbital station Salyut 4. The first mission of 30 days was flown by A. A. Gubarev (Commander) and G. M. Grechko (Flight Engineer) and the second mission of 63 days by P.I. Klimuk (Commander) and V.I. Sevastyanov (Flight Engineer). The present paper gives preliminary data on the general health and cardiovascular investigations of the crew members during and after flight. The clinical and physiological examinations of the cosmonauts showed that the work-rest cycles and counter-measures used helped to maintain their good health and high performance in flight, to alleviate adverse reactions and to facilitate readaptation post-flight. Medical results of the post-flight investigations revealed no changes that may detract from further increasing the duration of manned space missions.

The role of gravity in the phylogeny of structure and function in animal sensors of spatial orientation, and their predicted action in weightlessness

The evolution of the structural, functional and cytochemical organization of the gravity receptor which determines a body position in the gravitational field of the earth by means of muscular regulation was traced both invertebrates and vertebrates, using electron microscopic and histochemical methods. In the course of evolution of vertebrates, the specialized gravity receptor-statocyst which, as a rule, consists of primary sensory cells and supplies otoliths, is formed. In vertebrates, there exists a vestibular apparatus made up of secondary sensory cells and also having otoliths. The receptor cells, both of statocysts and the vestibular apparatus, are supplied with special antennas (kinocilia and stereocilia). Deviation of the antennas stimulated by displacement of the otoliths resulting from locomotor activity of animals leads to excitation of the receptor cells. When exposed to a modified gravitational field (linear accelerations of 10 g, for 3 min), the receptor cells of the vestibular apparatus, in all classes of vertebrates, show progressive changes in RNA content and protein synthesis (increase followed by decrease) which return to normal only after 12 days. Thus, immediate transfer of animals and man from acceleration to weightlessness appears to be a reason for movement disease. The above consideration showed the need for an experiment in which an animal (with its vestibular apparatus) which had not undergone previous accelerations, would be exposed to weightlessness. Frog embryos, Rana temporaria, at the stage preceding the organogenesis, when the vestibular apparatus and other organs were lacking, were chosen as a suitable subject. Frog embryos at the stage of an early gastrula were placed in a special container Emkon aboard the Soyuz 10 spacecraft. After short accelerations, they were exposed to weightlessness for 44 hours. The embryos were allowed to continue to develop to the stage of early tail bud. The experimental embryos showed normally developed acoustic vesicles and vestibular ganglia. Clear differentiation of the receptor cells with antennas (kinocilia and stereocilia) was found in the acoustic vesicles. Thus, in weightlessness, vestibular apparatus develops just as well as in the gravitational field of the earth. However, only a much longer stay in weightlessness conditions will indicate whether there are any changes in the structural, cytochemical and functional organization of vestibular apparatus. The similarity in the structural, functional and cytochemical organization of the gravity receptor in vertebrates and invertebrates appears to allow the prediction of the behaviour of the gravity receptor as a whole, and of its receptor elements, both in normal and changed gravitational fields. The first attempts were carried out only on the vestibular apparatus of vertebrates.

Some results of medical investigations performed during the flight of the research orbital station Salyut

The paper presents the main results of physiological studies carried out during the flight of the Salyut station. Details of atmospheric composition, diet, provisions for personal hygiene, the on-board medical kit, prophylactic measures, work and rest schedule are given. Methods of investigation, particularly for studying the cardiovascular response, are described, including tests using the application of lower body negative pressure. The subjective and objective in-flight condition of the cosmonauts is dealt with in detail. An evaluation of the cardiovascular response is made, as compared with previous flights, both at rest and during tests. Results of clinical and biochemical studies of the blood, certain indices of visual perception and microbiological investigations are described. It is concluded that the observed physiological changes are reversible.

Results of medical investigations carried out on board the Salyut orbital stations

The purpose of the medical investigations carried out in flights of the Soviet orbital station Salyut were: to further studies and clarification of the phenomenology and mechanisms of changes in the main functions of the human body during prolonged weightlessness; to accumulate additional data on human responses at an early stage of adaptation to weightlessness; to assess the effectiveness of countermeasures against adverse effects of weightlessness during and after flight. The orbital station was equipped with a set of countermeasuring devices: a trainer for physical exercises (a treadmill), gravity simulation suit for long wear, bicycle ergometer, anti-G suit to be worn immediately post-flight, drugs, etc. The system of medical control included daily recordings of electrocardiography and respiration and regular physical examinations using provocative tests (physical exercises of a known force, lower-body negative pressure). Specific biomedical investigations were performed before, during and after flight. As in previous flights, the atmosphere in the habitable modules was similar to that on the earth. Food supply met the requirements for basic nutrients and satisfied individual preferences of the crew members. In addition to the time required to fulfil the flight programme, the work-rest schedule allowed the cosmonauts 8 hours sleep, four meals, 2.5 hours physical training and personal time. The biomedical investigations carried out during and after flight furnished information towards a better understanding of human responses to the effects of space flight factors and the mechanisms underlying their development.

Soviet experiments aimed at investigating the influence of space flight factors on the physiology of animals and man

Results are given of biological experiments on space ship-satellites II, III, IV and V, and of scientific investigations made during the flights of Cosmonauts Gagarin and Titov aboard space ships Vostok I and Vostok II. Physiological reactions to the action of the flight stress-factors are not of a pathological character. In the post-flight period no alterations in health conditions of either cosmonauts or animals were observed. At the same time some peculiarities which were revealed while analyzing physiological reactions and a number of biological indices require further investigations. The most important tasks remaining are to study the influence of protracted weightlessness, of the biological action of space radiation, of the action of acceleration stresses after prolonged stay under zero-gravity conditions and also to analyze the influence on the organism of the whole combination of spaceflight factors, including emotional strain. In the Soviet Union, a great number of biological experiments have been conducted with a view to elucidating the action of space flight factors on living organisms and the design of systems necessary to ensure healthy activity during flight aboard rocket space vehicles. The first flight experiments with animals were conducted by means of geophysical rockets. The next step in this direction was made by the launching of Sputnik II in 1957 and by experiments on space ship-satellites in 1960-61. The main purpose of flight and laboratory investigations was to obtain the objective scientific criteria essential for ensuring the safety of manned space flight.

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.

Satellite biological experiments--major results and problems

The data on the results of biological experiments carried out on Vostok 5 and Vostok 6 are presented. Space flight factors are shown to cause in hereditary structures of some biological objects (seeds of higher plants, lysogenic bacteria, Tradescantia microspores, etc.) distortions of a small but statistically significant value. Changes in physiological functions of certain objects (seeds of higher plants, etc.) have been also detected. These data are in good agreement with the results of flight experiments carried out in 1960-1962. Prospects of research of the biological effect of cosmic radiation and weightlessness are considered with respect to flight experiments.

[From 108 minutes to 438 days and further on... (on the 40th anniversary of Iu. A. Gagarin's flight)]

The progress of science and technology at the end of the XIXth and first half of the XXth century paved the way to start space exploration by humanity. The flight of Yu. A. Gagarin on April 12, 1961 was one of the history watersheds that had a great many of social implications. Piloted missions to space demonstrated the possibility for humans to adapt to the spaceflight factors which, nonetheless, can provoke various unfavorable reactions, particularly on return to Earth. Step-by-step extension of mission length paralleled enhancement of the methods of monitoring of crew health, life support systems, and development of modalities to maintain crew health and performance. The paper contains brief discussion of data acquired in short- and long-term missions including the 438-d mission of cosmonaut-physician V.V. Polyakov. The final section is devoted to the mainstream problems of future piloted space programs.

[Main areas and results of research at the Institute of Biomedical Problems in 1963-1998]

The paper features the history of the Institute of Biomedical Problems (IBMP), the Russian leading institution in space biology and medicine, and the advances achieved by researchers over 35 years since its foundation. Special attention is devoted to the contribution of the Institute to the establishment of international co-operation in human space flight and space life sciences. Future of the space life sciences and humans in space is outlined.

Milestones of space medicine development in Russia (establishment and evolution of the Institute of Biomedical Problems)

This paper describes the history of the Institute of Biomedical Problems (IMBP): its birth and development. IMBP's directors were: Andrei V. Libedinsky (1963-1965), Vasily V. Parin (1965-1967), Oleg G. Gazenko (1968-1988), and Anatoly I. Grigoriev (1988 to the present). Most of the early employees of IMBP came from the USSR Air Force Institute of Aviation Medicine and the USSR Ministry of Health Institute of Biophysics. The major goals of IMBP were: development of a system of medical monitoring and support of long-duration space missions, selection and training of civilian crew members, bioengineering testing of flight equipment, and development of life support system concepts and requirements. The paper presents major results of the above research activities.

[Nikolaĭ Nikalaevich Sirotinin and his school]

In a brief review of 50-year scientific activity of professor N. N. Sirotinin and his students the authors emphasize that this broad-minded scientist contributed to development of such disciplines as microbiology, pathophysiology, high-altitude, aerospace medicine. However, his main goal was evolution of reactivity and resistance, approaches to perfection of human health and performance. Much attention was paid to effects of low partial oxygen pressure on human and animal body, to hypoxic states of different origin. Methods of hypoxytherapy and hypoxic training are widely used in Russia and abroad. The contribution of academician N. N. Sirotinin to modern pathophysiology, high-altitude and aerospace physiology, internal and sport medicine is highly appreciated in Russia.

[Results of medical studies in relation to the program of the second space flight on the orbital complex "Mir"]

In 1987, the USSR cosmonauts Y. V. Romanenko (326 days), A. I. Laveikin (approximately 176 days), and A. P. Alexandrov (approximately 160 days) made a space mission on Mir. (A. I. Laveikin showed specific cardiovascular responses to exercise tests and was therefore replaced with A. P. Alexandrov). The most important medical result of this mission was that Yu. V. Romanenko, who remained in orbit for 3 months longer than anyone before, working intensively, did not exhibit any changes that were qualitatively different from those observed in previous long-duration space flights. The health status and work performance of other crewmembers were also good, although each of them showed individual responses. The postflight recovery period went smooth.

[Habitability and biological life support systems for man]

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.

[Medical studies concerning the program of long-term manned space flights on "Saliut-7"-"Soiuz-T" orbital complex]

During 1982-1986 the orbital complex Salyut-7--Soyuz-T was visited by six long-term (from 65 to 237 days) principal crews and five short-term (from 8 to 12 days) visiting crews. Many medical investigations were performed during those missions, especially during the longest 237-day flight in which a physician-cosmonaut took part. The objective of the investigations was to accumulate new data and complementary information about physiological responses to microgravity. The methods and procedures used were in part the techniques, which were employed in previous missions but modified to meet specific requirements, and in part new techniques such as echocardiography for cardiovascular measurements, various loading tests, sensory tests, and blood and urine biochemistry.

[Medical studies during an 8-month flight on the orbital complex "Saliut-7"--"Soiuz-T"]

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.

Central and regional hemodynamics in prolonged space flights

This paper presents the results of measuring central and regional (head, forearm, calf) hemodynamics at rest and during provocative tests by the method of tetrapolar rheography in the course of Salyut-6-Soyuz and Salyut-7-Soyuz missions. The measurements were carried out during short-term (19 man-flights of 7 days in duration) and long-term (21 man-flights of 65-237 days in duration) manned missions. At rest, stroke volume (SV) and cardiac output (CO) as well as heart rate (HR) decreased insignificantly (in short-term flights) or remained essentially unchanged (in long-term flights). In prolonged flights CO increased significantly in response to exercise tests due to an increase in HR and the lack of changes in SV. After exercise tests SV and CO decreased as compared to the preflight level. During lower body negative pressure (LBNP) tests HR and CO were slightly higher than preflight. Changes in regional hemodynamics included a distinct decrease of pulse blood filling (PBF) of the calf, a reduction of the tone of large vessels of the calf and small vessels of the forearm. Head examination (in the region of the internal carotid artery) showed a decrease of PBF of the left hemisphere (during flight months 2-8) and a distinct decline of the tone of small vessels, mainly, in the right hemisphere. During LBNP tests the tone of pre- and postcapillary vessels of the brain returned to normal while PBF of the right and left hemisphere vessels declined. It has been shown that regional circulation variations depend on the area examined and are induced by a rearrangement of total hemodynamics of the human body in microgravity. This paper reviews the data concerning changes in central and regional circulation of men in space flights of different duration.

Review of basic medical results of the Salyut-7--Soyuz-T 8-month manned flight

This paper presents the results of medical investigations performed in the Salyut-7 8-month mission in which a professional physician took part. The paper contains anthropometric measurements, results of investigating the vestibular function, cardiovascular function at rest and in response to multi-step tests (with emphasis on echocardiographic measurements), metabolic parameters and hormonal status. It also discusses medical aspects of the extravehicular activity. The medical investigations, although some new methods were applied, provided the continuity of methodical approaches and data accumulated in previous missions.

Medical problems of manned space flights onboard orbital stations

Medical aspects of crew safety and life support as well as biomedical investigations form part and parcel of the preparation and conduct of manned space programs. The list of biomedical problems related to these programs is very long. The present paper concentrates on some of them.

[Experiments on rats exposed in the Cosmos 1667 biosatellite (goals, protocols, results)]

Morphobiochemical investigations of the rats flown on the biosatellite Cosmos-1667 have shown that the 7-day space flight produces shifts in different systems, organs and tissues which reflect adaptive processes to microgravity. Early signs of structural, functional and metabolic rearrangement can be detected in the musculoskeletal apparatus, hemopoietic system, lymphoid organs, neurohormonal systems, i.e., in the systems and organs that develop changes during long-term flights. The rates of adaptation to microgravity are different not only in various systems and organs but also within the same tissues. Most shifts that emerge at an early stage of adaptation to microgravity progress with flight time but some of them develop to a full extent after the 7-day flight. The specific feature of the early stage of adaptation to microgravity is the lack of significant changes in blood biochemistry in the presence of structural and metabolic changes in tissues. This fact gives evidence that the mechanisms maintaining homeostasis at the organism level are not as yet disrupted during 7 days of flight.

[The 20th anniversary of our journal]

This review describes the history of the journal--its establishment and development associated with the advances in space biology and aerospace medicine. The paper summarizes the major areas of research discussed in the publications and emphasizes their relations with other branches of science. It also lists readers' comments, suggestions and recommendations derived form the recent questionnaires. The paper outlines the objectives of the journal as related to further development of space biology and aerospace medicine.

Cardiovascular changes in prolonged space flights

In prolonged manned space flights, the cardiovascular function was examined at rest and during provocative tests. As compared to the preflight data the following changes were seen: higher heart rate at rest and during LBNP tests, decrease of stroke volume at rest and during LBNP test and a less marked increase (or decrease) during exercise tests, symptoms of a greater heart load which transformed to the syndrome of myocardial hypodynamics (preload) during LBNP tests or to the syndrome of myocardial hyperdynamics (afterload) during exercise tests (with other than preflight ratios of systolic and diastolic time intervals). The above cardiovascular changes did not, as a rule, aggravate with flight time and can be viewed as adaptive reactions to microgravity. The above cardiovascular changes were primarily produced by fluid redistribution in the cranial direction, diminished participation of the muscle system in circulation, and involvement of unloading reflexes from the cardiopulmonary receptor zones.

Investigations onboard the biosatellite Cosmos-1667

The program of the 7-day flight of the biosatellite Cosmos-1667 launched in July 1985 included experiments on two rhesus monkeys, ten Wistar SPF rats, ten newts, Drosophila flies, maize seedlings, lettuce sprouts, and unicellular organisms--Tetrahymena. The primate study demonstrated that transition to orbital flight was accompanied by a greater excitability of the vestibular apparatus and an increased linear blood flow velocity in the common carotid artery. The rat studies showed that atrophy of antigravity muscles and osteoporosis of limb bones developed even during short-term exposure to microgravity. The experiments on other living systems revealed no microgravity effects on the cell division rate, proliferative activity of cells of regenerating tissues and organs, energy metabolism of developing insects, structure or chemical composition of higher plant seedlings.

Fluid-electrolyte metabolism and renal function of white rats in experiments aboard Cosmos biosatellites

Rat experiments on the Cosmos biosatellites demonstrated that the percentage of renal excretion of consumed water after flight was lower than after synchronous experiment. This can be attributed not only to water retention but also to a different level of extrarenal losses postflight. Weightless rats showed increased sodium excretion after water load tests and increased potassium excretion after potassium load tests. The sodium, potassium, and calcium balance was positive after weightlessness. Analysis of the electrolyte composition of different kidney zones revealed a decreased potassium content in the medulla, which is considered to be one of the causes of changed renal iono- and osmoregulatory function in weightlessness. The normalizing effect of artificial gravity on the natri- and kaliuretic renal function was demonstrated.

[Main results of the medical research in the Saliut 6-Soiuz program]

In 1977-1981 the Soviet Union launched 18 manned space missions under the Salyut-6--Soyuz program which included five flights of prime crews for 96, 140, 175, 185, and 75 days and eleven flights of visiting crews. Altogether 30 cosmonauts, including 9 crewmembers from other than the USSR socialist countries, took part in the program. Emphasis was given to the medical investigations, since their purpose was not only to assess the health status of the crewmembers and to investigate their responses to prolonged weightlessness, but also to identify the maximum allowable flight time.

[Results of medical research in the performance of the long-term manned flights of the Saliut-6 program]

The major goal of biomedical investigations in prolonged (up to 6 months) manned missions was to obtain information about physiological reactions to long-term weightlessness and to carry out detailed clinical, physiological, immunological and anthropometric investigations before, during and after flight. The results obtained give evidence that man can adapt to the prolonged exposure and to maintain good health condition and high work capacity. The changes detected postflight were reversible and disappeared completely within a relatively short time period. The changes were not correlated with the flight duration. The good health condition and high performance inflight were maintained and postflight readaptation was facilitated due to a rational work-rest cycle and specific countermeasures which were modified with respect to the results of regular medical examinations. Salyut-6 medical data have demonstrated that the duration of forthcoming manned missions can be extended.

Investigations on-board the biosatellite Cosmos-83

The program of the 5 day flight of the biosatellite Cosmos-1514 (December 1983) envisaged experimental investigations the purpose of which was to ascertain the effect of short-term microgravity on the physiology, growth and development of various animal and plant species. The study of Rhesus-monkeys has shown in that they are an adequate model for exploring the mechanisms of physiological adaptation to weightlessness of the vestibular apparatus and the cardiovascular system. The rat experiment has demonstrated that mammalian embryos, at least during the last term of pregnancy, can develop in microgravity. This finding has been confirmed by fish studies. The experiment on germinating seeds and adult plants has given evidence that microgravity produces no effect on the metabolism of seedlings and on the flowering stage.

Medical results of Salyut-6 manned space flights

The major goal of medical investigations in the USSR longterm (up to 6 months) manned space flights was to accumulate information on human responses to prolonged weightlessness. Before, during and after these flights, detailed clinical, physiological, immunological and anthropometric examinations were conducted. The examinations demonstrated that man may well adapt to long-term space flight, retaining good health and a high work capacity. The changes seen postflight were reversible and disappeared completely after a relatively short readaptation period. Postflight changes did not correlate with the flight duration. A reasonable work-rest cycle and various physiological countermeasures were used, the efficiency of which were substantiated by means of regular medical examinations. These methods helped the cosmonauts to maintain good health status and adequate performance inflight and facilitated their readaptation postflight. Medical investigations performed during the Salyut-6 flights indicate that the duration of manned space flight can be increased.

Effects of various countermeasures against the adverse effects of weightlessness on central circulation in the healthy man

The effect of lower body negative pressure, local negative pressure below the knee joint, and both pneumatic and mechanical occlusion cuffs at the upper third of the femur on central circulation, oxidative metabolism, and acid-base equilibrium of blood was studied on eight healthy male volunteers with doublelumen Swan-Ganz flow-directed thermodilution catheters implanted for 7 d into the pulmonary artery. The counter-measures against the adverse effects of weightlessness were used in two regimens: regimen I at -30, -50, +40 torr and regimen II at -60, -100, and +60 torr. The parameters were recorded in recumbency, during the head up tilt at 70 degrees for 15 min, and then during the head-down tilt at -20 degrees for 60 min. After the first 20 min of anti-orthostasis, the effects of the above countermeasures in the two regimens were investigated. The tile-induced changes in central circulation, those observed during application of the countermeasures, and the effect of different countermeasures were studied on a comparative basis. It was demonstrated that the highly informative method of implantation of catheters into the pulmonary artery can be successfully used in biomedical investigations of normal men.

[Space biology in the 3d decade]

The paper reviews the major results of experiments on microorganisms, plants and animals flown onboard space vehicles during the past two decades. To explain the experimental findings, it is hypothesized that living beings develop an indirect adaptation to gravity effects which has a bearing only on the phylogenetic process.

Summary of medical investigations in the U.S.S.R. manned space missions

The results of biomedical investigations carried out in the U.S.S.R. manned space missions are discussed. Their basic result is well-documented evidence that man can perform space flights of long duration. The investigations have demonstrated no direct correlation between inflight or postflight physiological reactions of crewmembers and flight duration. In all likelihood, this can be attributed to the fact that special exercises done inflight efficiently prevented adverse effects of weightlessness. However, human reactions to weightlessness need further study. They include negative calcium balance and anemia as well as vestibulo-autonomic disorders shown by crewmembers at early stages of weightlessness. Attention should be given to psychological, social-psychological and ethical problems that may also limit further increase in flight duration.

[Animal experiments on the cosmos series biosatellites (results and prospects)]

Results of animal (rat) experiments carried out onboard biosatellites Cosmos-605, 690, 782, 936 and 1129 are presented with emphasis on changes in metabolism and musculo-skeletal system. The modifying effect of weightlessness on the animal radiosensitivity is considered. The use of artificial gravity as a countermeasure against adverse effects of weightlessness is discussed. As an immediate perspective, primate experiments aimed at a detailed study of mechanisms of weightlessness induced changes in the structure and function of the cardiovascular, musculo-skeletal and vestibular systems are described.

Preliminary results of medical investigations during piloted flights in the Salyut-6 program

The changes observed during flight on the whole corresponded with the preflight prognosis and reflected the phase nature of the processes of adaptation. They were shown by blood redistribution symptoms, fluctuations in the main indices of hemodynamics at rest not going beyond the limits of the physiological norm, an increase in the pulse-filling of the head with blood, and a decrease in that of the shank. The reaction of the blood circulation to a physical load and the application of negative pressure varied, and in a number of investigations during flight it was more pronounced than on Earth. The changes observed after the flight appeared regular for the period of readaptation of the reactions of the organism. These reactions bore a functional nature and qualitatively did not differ from reactions observed after other flights, and after the 140-day flight they were, on the whole, less pronounced than after the 96-day flight. In the postflight period to accelerate the process of adaptation a complex of restorative-healing measures was carried out, including mainly a regulation of motor activity, restorative massage of the muscles, remedial physical culture and aquatic procedures. The flight lasting 140 days revealed no contraindications to a further regular increase in the time of cosmic flights and demonstrates once again the possibility of the planned control of the state of a healthy subject in flight and the readiness of the organism for a return to the terrestrial force of gravity.