[Biological systems of life support for space crews: some results and anticipations].

One of the challenges for space biology and medicine is resolution of lots of problems of biomedical support of humans in the extreme environment of space flight. These problems include also designing of robust and efficiently functioning life support systems (LSS). The paper gives an overview of the investigations of ground-based BLSS with human subjects conducted in Russia and other countries. Also, it contains the basic data of studying the BLSS photoautotrophic components (higher plants) in the series of experiments with the total duration of 630 days fulfilled on orbital complex Mir and the series of experiments with the total duration of 820 days in the ISS Russian segment. Analysis of the results from the BLSS investigations on Earth and in space flights drives to the conclusion that some of the BLSS components, greenhouses specifically, can be integrated even now into the currently used systems of space crew life support.

[Growth, development and genetic status of pea plants cultivated in space greenhouse "LADA"].

In the period between March 2003 and April 2005 five crops of genetically marked dwarf pea were cultivated in greenhouse LADA on the ISS Russian segment to study morphology and genetics in consecutive generations. Results of the first space experiment were analyzed and characteristics of ground plants grown from space seeds were studied. It was shown that parameters of growth, development and genetic status of pea plants that completed the ontogenetic cycle in LADA did not differ substantially from the laboratory control and that plants cultivated in space flight do not incur losses in the reproductive function and form viable seeds. Genetic analysis of plants from the first generation of space and ground seeds using the methods of RAPD-primers (10 markers) and chromosomal aberration analysis failed to reveal genetic polymorphism which means that the spaceflight factors had no effect on the genetic apparatus of the first generation of space-grown plants.

[Biological processes of the human environment regeneration within the Martian crew life support systems]. / Biologicheskie protsessy regeneratsii sredy obitaniia v sisteme zhizneobespecheniia ékipazha marsianskoi ékspeditsii.

Five ground-based experiments at RF SRC-IBMP had the purpose to make a thorough investigation of a model of the human-unicellular algae-mineralization life support system. The system measured 15 m3 and contained 45 liters of alga suspension; the dry alga density was 10 to 12 g/l and water volume (including the alga suspension) amounted to 59 l. More sophisticated LSS models where algae were substituted by higher plants (crop area in the greenhouse equaled 15 m2) were investigated in three experiments from 1.5 mos. to 2 mos. in duration. It was found that the alga containing LSS was able to fulfill not only the macrofunction (air and water regeneration) but also several additional functions (air purification, establishment of microbial cenosis etc.) providing an adequate human environment. This polyfunctionality of the biological regenerative processes is a weighty argument for their integration into space LSSs. Another important aspect is that the unicellular algae containing systems are highly reliable owing to a huge number of species-cells which will be quickly recovered in case of the death of a part of the population and, consequently, functionality of the LSS autotrophic component will be restored before long. For an extended period of time the Martian crew will have no communication with the Earth's biosphere which implies that LSS should be absolutely reliable and redundant. Redundancy can be achieved through installation aboard the vehicle of two systems constructed on different principles of regeneration, i.e. physical-chemical and biological. Each of the LSSs should have the power to satisfy all needs of the crew. The best option is when two systems are functioning in parallel sharing the responsibility for the human environment. Redundancy in this case will mean that in the event of failure or a drastic decrease in performance of one system the other one will make up for the loss by increasing its share in the overall regeneration process.

[The evaluation of the error of the thermal pulse technique used to measure moisture content of root substrates in space greenhouse]. / Otsenka pogreshnosti teploimpul'snogo metoda izmereniia vlagosoderzhaniia korneobitaemykh sred dlia kosmicheskikh oranzherei.

Point thermopulse probes were used to monitor moisture level in the root substrates during cultivation of higher plants in a space greenhouse. Investigated were performance data of the thermopulse moisture probe in integration with the space greenhouse. It was shown that within the substrate moisture range from 20 up to 100% of the full saturation the technique error does not exceed 1.5%. The thermopulse technique bears much promise for metrologic monitoring of the root substrate moisture content in space greenhouses no matter water and air supply technology.

[Growth and development of plants in a sequence of generations under the conditions of space flight (experiment Greenhouse-3)]. / Rost i razvitie rastenii v riadu pokolenii v usloviiakh kosmicheskogo poleta v éksperimente "Oranzhereia-3".

The purpose was to study characteristic features of growth and development of several plant generations in space flight in experiment GREENHOUSE-3 as a part of the Russian-US space research program MIR/NASA in 1997. The experiment consisted of cultivation of Brassica rapa L. in board greenhouse Svet. Two vegetative cycles were fully completed and the third vegetation was terminated on day 13 on the phase of budding. The total duration of the space experiment was 122 days, i.e. same as in the ground controls. In the experiment with Brassica rapa L. viable seeds produced by the first crop were planted in space flight and yielded next crop. Crops raised from the ground and space seeds were found to differ in height and number of buds. Both parameters were lowered in the plants grown from the space seeds. The prime course for smaller size and reduced organogenic potential of plantTs reproductive system seems to be a less content of nutrients in seeds that had matured in the space flight. Experiment GREENHOUSE-3 demonstrated principle feasibility of plant reproduction in space greenhouse from seeds developed in microgravity.

[Growth and development of plants in a row of generations under the conditions of space flight (experiment Greenhouse-5)]. / Rost i razvitie rastenii v riadu pokolenii v usloviiakh kosmicheskogo poleta v éksperimente "Oranzhereia-5".

Results of the experiment aimed at harvesting a second space generation of wheat var. Apogee in Mir greenhouse Svet (experiment GREENHOUSE-5) are presented. In space flight, germination rate of space seeds from the first crop made up 89% against 100% of the ground seeds. The full biological ripeness was observed in 20 plants grown from the ground seeds and one plant grown from the space seeds following 80- to 90-d vegetation. The plant of the second space generation was morphologically different neither from the species in the first space crop nor from the ground controls. To study the biological characteristics of Apogee seeds gathered in the first and second crops in spaceflight experiment GREENHOUSE-5, the seeds were planted on their return to the laboratory. Morphometric analysis showed that they were essentially similar to the controls. Hence, the space experiments in Mir greenhouse Svet performed during 1998-1999 gave proof that plants cultivated in microgravity can pass the ontogenetic cycle more than once. However, initial results of the investigations into growth and development of plants through several generations are still in-sufficient to speak of possible delayed effects of the spaceflight factors (microgravity, multicomponent radiation, harmful trace contaminants etc.).

[Growth of wheat from seed-to-seed in space flight]. / Vyrashchivanie pshenitsy "ot semeni do semeni" v usloviiakh kosmicheskogo poleta.

In our earlier space experiment with super dwarf wheat we found the spikes developed in space to be barren. The cause of the full crop sterility was sensitivity of this wheat species to the ethylene concentration of 0.3-0.8 mg/m3 during the experiment. The follow-up ground experiments were made to identify species of dwarf wheat that could be raised in space greenhouse Svet and are distinguished by partial tolerance of their reproductive organs to elevated ethylene in air. The choice fell on the USU-Apogee cultivar specially developed for planting in growth chambers as an integral part of various bioregenerative life support systems, including the space ones. An experiment with wheat Apogee was performed in greenhouse Svet on board MIR. The period of the full crop vegetation cycle was not significantly altered under the spaceflight conditions. The experiment yielded 508 seeds from 12 plants, i.e. by 38% less than in laboratory experiments and by 69% more as compared with results of growing crops in ethylene-contaminated atmosphere (1 mg/m3). Mass of the space seeds was low if compared with the laboratory crops. This was the first time when the feasibility of gathering seeds from wheat that had passed the whole vegetation cycle in space flight was demonstrated. The experiment will give mightly impetus to the advancement of research on space biological LSS and gravitational biology.

[Biological life support systems: investigations on board of orbital complex "Mir"]. / Biologicheskie sistemy zhizneobespecheniia: issledovaniia na bortu orbital'nogo kompleksa "Mir".

From 1989 till 1998 twelve experiments were performed by Bulgarian, Russian, Slovak, and US researchers and engineers on the effects of space flight on the model of ecosystem "algae-fishes-bacteria", and ontogenesis of birds (Japanese quail) and higher plants. For the first time several viable chicks were hatched and passed the whole cycle of their embryonic development in the MIR microgravity. The length of the plant ontogenetic cycle as a whole and its specific stages appeared to be same as on Earth. Seeds of Brassica rapa gathered and planted in greenhouse Svet on board MIR yielded robust shoots. Photosynthesis and dark respiration of plants growing in spaceflight were successfully measured.

[Some peculiar features of liquid supply to the root medium of plants growing in microgravity]. / Nekotorye osobennosti obespecheniia korneobitaemoi sredy pri kul'tivirovanii rastenii v usloviiakh nevesomosti.

Sixteen point probes monitored moisture level in the root medium of the wheat plants grown in greenhouse SVET on the MIR/NASA space science program. The article outlines types of water migration in the absence of gravity. Hydrophysical characteristics of perspective root media have been explored. Results of the water supply monitoring and control in the course of experiment are reported. The authors put forward porous root media to facilitate water migration and aeration.

[Evaluation of super dwarf wheat growth and development in greenhouse "Svet" during cultivation in inhabited pressurized chamber]. / Issledovanie rosta i razvitiia superkarlikovoi pshenitsy v oranzheree "Svet" pri kul'tivirovanii v obitaemom germoob''ekte.

Goals of the 3-month experiment GREENHOUSE using the equipment of greenhouse SVET (ECO-PSY-95) were to feature growth and development of wheat through the entire cycle of ontogeny under the maximally mimicked MIR environment, and to try out the procedures and timeline of space experiment GREENHOUSE-2 as a part of the fundamental biology investigations within the MIR/NASA space science program. Irradiation intensity (PAR) was 65 W/m2 and 38 W/m2 in the experiment and laboratory control, respectively. Values of other environmental parameters were MIR average (18-25 degrees C, relative air humidity in the interval between 40% and 75%, total gas pressure of about 660 to 860 mm Hg, partial oxygen pressure within the range from 140 to 200 mm Hg, partial carbon dioxide pressure up to 7 mm Hg). Experimental results showed that wheat cultivation in inhabited chamber under a modified lighting unit providing greater irradiation of the crop area produced more plant mass although seed production dropped. Low grain content in ears could be the aftermath of the gaseous trace contaminants in the chamber atmosphere.