Summary of the proceedings of the Mars Surface Sample Return Symposium

A summary is made of various technical and scientific aspects of a Mars surface sample return mission. Particular attention was focused on the question of back contamination. Data are also given on problems inherent in the back contamination issue and return sample mission; areas where additional research is needed were pointed out. Quarantine procedures, safety measures, and sterilization effects on organic-inorganic data, and biological problems were also dealt with

Speculations on the consequences to biology of space shuttle-associated increases in global UV-B radiation

Various aspects of the impact of ozone depletion on the biosphere are assessed and discussed. Speculations on the factors which determine the extent and nature of biological damage due to an increased flux of ultra violet light are presented. It is concluded that a complete assessment must consider both direct effects (organisms) as well as indirect effects (ecosystems). The role of computer simulation of ecosystem models as a predictive tool is examined

Controlled ecological life support system - biological problems

The general processes and controls associated with two distinct experimental paradigms are examined. Specific areas for research related to biotic production (food production) and biotic decomposition (waste management) are explored. The workshop discussions were directed toward Elemental cycles and the biological factors that affect the transformations of nutrients into food, of food material into waste, and of waste into nutrients were discussed. To focus on biological issues, the discussion assumed that (1) food production would be by biological means (thus excluding chemical synthesis), (2) energy would not be a limiting factor, and (3) engineering capacity for composition and leak rate would be adequate

Space ecosynthesis: An approach to the design of closed ecosystems for use in space

The use of closed ecological systems for the regeneration of wastes, air, and water is discussed. It is concluded that such systems, if they are to be used for the support of humans in space, will require extensive mechanical and physico-chemical support. The reason for this is that the buffering capacity available in small systems is inadequate, and that natural biological and physical regulatory mechanisms rapidly become inoperative. It is proposed that mathematical models of the dynamics of a closed ecological system may provide the best means of studying the initial problems of ecosystem closure. A conceptual and mathematical model of a closed ecosystem is described which treats the biological components as a farm, calculates the rates of flow of elements through the system by mass-balance techniques and control theory postulates, and can evaluate the requirements for mechanical buffering activities. It is suggested that study of the closure of ecosystems can significantly aid in the establishment of general principles of ecological systems

Controlled Ecological Life Support Systems: CELSS 1985 Workshop

Various topics related to closed ecological systems are discussed. Space habitats, vegetative growth, photosynthesis, recycling, culture techniques, waste utilization bioreactors and controlled atmospheres on space stations are among the topics covered

A review of recent activities in the NASA CELSS program

A CELSS (Controlled Ecological Life Support System) is a device that utilizes photosynthetic organisms and light energy to regenerate waste materials into oxygen and food for a crew in space. The results of studies with the CELSS program suggest that a bioregenerative life support system is a useful and effective method of regenerating consumable materials for crew sustenance. The data suggests that the operation of a CELSS in space is practical if plants can be made to behave predictably in the space environment. Much of the work centers on the biological components of the CELSS system. Ways of achieving high efficiency and long term stability of all components of the system are examined. Included are explorations of the conversion of nonedible cellulose to edible materials, nitrogen fixation by biological and chemical methods, and methods of waste processing. A description is provided of the extent to which a bioregenerative life support system can meet the constraints of the space environment, and the degree is assessed to which system efficiency and stability can be increased during the next decade

The response of selected terrestrial organisms to the Martian environment: A modeling study

An energy balance model has been developed to investigate how the Martian atmospheric environment could influence a community of photosynthetic microorganisms with properties similar to those of a cyanophyte (blue-green algal mat) and a lichen. Surface moisture and soil nutrients are assumed to be available. The model was developed to approximate equatorial equinox conditions and includes parameters for solar and thermal radiation, convective and conductive energy transport, and evaporative cooling. Calculations include the diurnal variation of organism temperature and transpiration and photosynthetic rates. The influences of different wind speeds and organism size and resistivity are also studied. The temperature of organisms in mats less than a few millimeters thick will not differ from the ground temperature by more than 10[deg]K. Water loss is actually retarded at higher wind speeds, since the organism temperature is lowered, thus reducing the saturation vapor pressure. Typical photosynthetic rates lead to the production of 10-6 to 10-7 mole O2 cm-2 day-1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23720/1/0000692.pd

Microbial life in volcanic lakes

Lakes in the craters of active volcanoes and their related streams are often characterised by conditions considered extreme for life, such as high temperatures, low pH and very high concentrations of dissolved metals and minerals. Such lakes tend to be transient features whose geochemistry can change markedly over short time periods. They might also vanish completely during eruption episodes or by drainage through the crater wall or floor. These lakes and their effluent streams and springs host taxonomically and metabolically diverse microorganisms belonging in the Archaea, Bacteria, and Eucarya. In volcanic ecosystems the relation between geosphere and biosphere is particularly tight; microbial community diversity is shaped by the geochemical parameters of the lake, and by the activities of microbes interacting with the water and sediments. Sampling these lakes is often challenging, and few have even been sampled once, especially in a microbiological context. Developments in high-throughput cultivation procedures, single-cell selection techniques, and massive increases in DNA sequencing throughput, should encourage efforts to define which microbes inhabit these features and how they interact with each other and the volcano. The study of microbial communities in volcanic lake systems sheds light on possible origins of life on early Earth. Other potential outcomes include the development of microbial inocula to promote plant growth in altered or degraded soils, bioremediation of contaminated waste or land, and the discovery of enzymes or other proteins industrial or medical applications