[Issues of biomedical support of explorations missions].

Sine qua non for piloted exploration missions is a system of biomedical support. The future system will be considerably different from the analogous systems applied in current orbital missions. The reason is the challenging conditions in expeditions to remote space. In a mission to Mars, specifically, these are high levels of radiation, hypomagnetic environment, alternation of micro- and hypogravity, very long mission duration and autonomy. The paper scrutinizes the major issues of medical support to future explorers of space.

[From the flight of Iu. A. Gagarin to the contemporary piloted space flights and exploration missions].

The first human flight to space made by Yu. A. Gagarin on April 12, 1961 was a crucial event in the history of cosmonautics that had a tremendous effect on further progress of the human civilization. Gagarin's flight had been prefaced by long and purposeful biomedical researches with the use of diverse bio-objects flown aboard rockets and artificial satellites. Data of these researches drove to the conclusion on the possibility in principle for humans to fly to space. After a series of early flights and improvements in the medical support system space missions to the Salyut and Mir station gradually extended to record durations. The foundations of this extension were laid by systemic researches in the fields of space biomedicine and allied sciences. The current ISS system of crew medical care has been successful in maintaining health and performance of cosmonauts as well as in providing the conditions for implementation of flight duties and operations with a broad variety of payloads. The ISS abounds in opportunities of realistic trial of concepts and technologies in preparation for crewed exploration missions. At the same, ground-based simulation of a mission to Mars is a venue for realization of scientific and technological experiments in space biomedicine.

[The contribution of academician Leon Abgarovich Orbeli and his school to the development of physiology of extreme conditions].

The paper is devoted to the role of Academician L. A. Orbeli and his school in foundation and development of extreme physiology. The works of L. A. Orbeli, his pupils and collaborators contributed to the advancement of key theoretical and applied aspects of hyperbaric physiology, flights in stratosphere, aviation physiology and medicine, space physiology and radiobiology.

[Functional plasticity of mammalian skeletal muscles under microgravity].

In the retrospective analysis of own experimental data and the literary overview of the slow-to-fast transformation of skeletal muscles (essentially postural and locomotor) in animals due to microgravity the authors scrutinize the muscle functional plasticity given heterodromous changes in the external mechanic field. Adaptation of the myofiber phenotype is ensured by polymorphism of muscle isoproteins and lability of the system providing energy for muscle contraction.

[Concept of the telemedicine system for a Martian mission].

The telemedicine concept for a mission to Mars is presented including the basic operational units and subsystems, and problems of elaboration and creation of the telemedicine system with the use of multilevel structure functional modeling.

[Biomedical support to a piloted Martian expedition]. / Mediko-biologicheskoe obespechenie pilotiruemoi marsanskoi ékspeditsii.

Review of the main problems of biomedical support (BMS) to a piloted mission to Mars has revealed a correlation of the BMS constituents and parameters with the specifics of this venture that makes it significantly different from the near-Earth flights. Success of the transit to Mars and back and safety of the planet explorers will hinge on the BMS system functionality in the harsh changing environment and power to ensure medical safety, health and performance of the crew. Particular emphasis has been placed on the necessity to enhance methods of crew selection and training, to develop an on-board medical center including an appropriate database, to search for high-efficiency countermeasures, to formulate prescriptions for resolution possible psychological problems in flight, and to design and manufacture regenerative life support and radiation protection systems.

Goals of biomedical support of a mission to Mars and possible approaches to achieving them.

The main medical and biological problems associated with a piloted mission to Mars are discussed. Prerequisites for the mission are described, based on our experience with biomedical support of prolonged piloted missions. The most important factors are developing countermeasures against the prolonged effects of microgravity and hypogravity; solving a complex of psychological problems; developing methods to protect against cosmic radiation; and creating effective and reliable life support systems. Some aspects of the likely risks involved in such a mission are also reviewed.

[Some medical problems of piloted mission to Mars]. / Nekotorye meditsinskie problemy pilotiruemoi marsianskoi ekspeditsii.

Medical provisions to planetary missions take in a wide spectrum of medical, engineering and organizational issues the goal of which is to provide good living conditions for humans in space, and to ensure physical and psychic health and performance of crew members during research activities on the Martian surface and soon after return to Earth. The article carefully reviews the problems of defining conceptual approaches to medical support in a mission to Mars. These approaches are grounded on the analysis of medical experience of prolonged orbital missions and prognosis of physiological shifts due to extension of mission up to 2 to 3 years including the period of stay on the Martian surface. Special attention is given to the key medical aspects of the mission, i.e. medical monitoring, countermeasures (including utilization of a short-arm centrifuge) against the adverse effects of microgravity on crew health and keeping-up useful skills and knowledge.

[The main trends in the development of the equipment for physiological studies on the Earth and in space]. / Osnovnye tendentsii v razvitii apparatury dlia fiziologicheskikh issledovanii na zemle i v kosmose.

Recent advances in electronics and computers are widely used in present-day physiological equipment. Microprocessors are part of hardware complexes and nonstandard equipment. This increases significantly experimenter's capabilities in terms of experimental control and data processing and storage. These trends acquire great significance for the production of space-oriented research equipment in which automation of experimental control and data processing is highly important. Examples of experimental equipment for space physiology studies designed and developed through cooperative efforts of the USSR, socialist countries, NASA, ESA, and CERMA are considered.

[Recovery of muscle functions in rats following prolonged movement restraint]. / Vosstanovlenie funktsii myshts u krys posle dlitel'nogo ogranicheniia podvizhnosti

Experiments were carried out to measure time and force parameters of isometric contractions and structural parameters of muscles of hind limbs of rats which were exposed to hypokinesia for 130 days and then were kept under surveillance for 3 months. During recovery certain functions of the contractile system returned to the normal. At the same time M. soleus displayed persistent changes that were indicative of atrophic developments. Unlike M. soleus where delayed contraction (due to an increase in the time of relaxation) was followed by losses in force, fast muscles (M. ext. digit. longus and M. plantaris) showed recovery of force parameters. They also exhibited delayed contraction due to an increase in the time of tension development and half-relaxation. These differences are associated with dissimilar function and structure of muscular fibers. On the whole, the pattern of recovery of the motor functions reflects responses to an increased load of the neuromuscular system of animals which are kept in large cages after prolonged hypokinesia.

On the mechanisms of changes in skeletal muscles in the weightless environment.

Some characteristics of muscle contraction and mechanical properties of two muscles (M. soleus and M. extensor digitorum longus) in Wistar rats after 22 days of weightlessness have been investigated. On the second day after return to earth, the following changes were evident: slowing of twitch responses of the muscles studied; shortening half tetanic contraction time (defined by point of interactions of the increasing curve with 50% level of the peak value) in soleus; a rise of tension in both muscles as shown by the curve "length-force"; an increase of twitch/tetanus ratio and fatigability in both muscles. During repeated study of muscle properties, on the 26th day after return to earth, there were not any significant changes in values of most the above mentioned indices except the diminished strength of soleus. Shortening of contraction time in slow antigravitary soleus muscle is believed to be a sign of adaptive change in its characteristics resulting from unloading under the conditioning of weightlessness. Increased stiffness and diminished strength of muscles are considered as functional signs of atrophic processes, developing in the experiment. Dynamics of functional changes, conditioned, as we believe, mainly by weightlessness and correlated with morphological and biochemical data obtained on analogous material, allows us to postulate a reversible character of the changes described.