Complex morphological variability in complex evaporitic systems: thermal spring snails from the Chihuahuan Desert, Mexico

Thermal springs in evaporitic environments provide a unique biological laboratory in which to study natural selection and evolutionary diversification. These isolated systems may be an analogue for conditions in early Earth or Mars history. One modern example of such a system can be found in the Chihuahuan Desert of north-central Mexico. The Cuatro Cienegas basin hosts a series of thermal springs that form a complex of aquatic ecosystems under a range of environmental conditions. Using landmark-based morphometric techniques, we have quantified an unusually high level of morphological variability in the endemic gastropod Mexipyrgus from Cuatro Cienegas. The differentiation is seen both within and between hydrological systems. Our results suggest that this type of environmental system is capable of producing and maintaining a high level of morphological diversity on small spatial scales, and thus should be a target for future astrobiological research.     

On the possibility of Earth-type habitable planets in the 55 Cancri system

We discuss the possibility of Earth-type planets in the planetary system of 55 Cancri, a nearby G8 V star, which is host to two, possibly three, giant planets. We argue that Earth-type planets around 55 Cancri are in principle possible. Several conditions are necessary. First, Earth-type planets must have formed despite the existence of the close-in giant planet(s). In addition, they must be orbitally stable in the region of habitability considering that the stellar habitable zone is relatively close to the star compared to the Sun because of 55 Cancri's low luminosity and may therefore be affected by the close-in giant planet(s). We estimate the likelihood of Earth-type planets around 55 Cancri based on the integrated system approach previously considered, which provides a way of assessing the long-term possibility of photosynthetic biomass production under geodynamic conditions.     

The challenges and opportunities of a commercial human spaceflight mission to the ISS

ESA astronauts' ISS flight opportunities are considered as a vital source to meet the utilisation, operation and political objectives that Europe has established for participating in the International Space Station programme. Recent internal ESA assessments have demonstrated that a rate of three flights per year for European Astronauts should be maintained as a minimum objective. The current flight rate is lower than this. In order to improve this situation, in the context of the activation of the ESA ISS Commercialisation programme, ESA is developing the conditions for the establishment of commercially based human spaceflights with the financial support of both ESA and the private sector or, in the future, only the latter. ESA is working in a Partnership with the space industry to facilitate the implementation of such projects and support customers with a range of end-to-end commercial services. The opportunities and challenges of a "commercial human spaceflight", involving a member of the European Astronaut Corps, or a privately employed flight participant, are discussed here.     

Subfreezing activity of microorganisms and the potential habitability of Mars' polar regions

The availability of water-ice at the surface in the Mars polar cap and within the top meter of the high-latitude regolith raises the question of whether liquid water can exist there under some circumstances and possibly support the existence of biota. We examine the minimum temperatures at which liquid water can exist at ice grain-dust grain and ice grain-ice grain contacts, the minimum subfreezing temperatures at which terrestrial organisms can grow or multiply, and the maximum temperatures that can occur in martian high-latitude and polar regions, to see if there is overlap. Liquid water can exist at grain contacts above about -20 degrees C. Measurements of growth in organisms isolated from Siberian permafrost indicate growth at -10 degrees C and metabolism at -20 degrees C. Mars polar and high-latitude temperatures rise above -20 degrees C at obliquities greater than ~40 degrees, and under some conditions rise above 0 degrees C. Thus, the environment in the Mars polar regions has overlapped habitable conditions within relatively recent epochs, and Mars appears to be on the edge of being habitable at present. The easy accessibility of the polar surface layer relative to the deep subsurface make these viable locations to search for evidence of life.     

Induced abnormality in Mir- and Earth grown Super Dwarf wheat.

Super-dwarf wheat grown on the Mir space station using the Svet "Greenhouse" exhibited morphological, metabolic and reproductive abnormalities compared with Earth-grown wheat. Of prominent importance were the abnormalities associated with reproductive ontogeny and the total absence of seed formation on Mir. Changes in the apical meristem associated with transition from the vegetative phase to floral initiation and development of the reproductive spike were all typical of 'Super-Dwarf' wheat up to the point of anthesis. Observation of ruptured anthers from the Mir-grown plants revealed what appeared to be normally developed pollen. These pollen gains, however, contained only one nuclei, while normal viable pollen is tri-nucleate. A potentially important difference in the flight experiment, compared with ground reference studies, was the presence of a high level of atmospheric ethylene (1,200 ppb). Ground studies conducted by exposing 'Super-Dwarf' wheat to ethylene just prior to anthesis resulted in manifestation of the same abnormalities observed in the space flight samples.     

Comment on estimating the solar proton environment that may affect Mars missions.

Estimates of the energetic proton environment for a Mars mission are generally extrapolated from the solar proton observations at 1 AU. We find that solar particle events may be divided into two general classes. Events dominated by a near-sun injection of particles onto interplanetary magnetic field lines leading to the spacecraft position represent the "classical" solar particle event associated with solar activity. This class of event will scale in radial distance by the classical power law extrapolation. The extended-interplanetary-shock source generates a maximum flux as the shock passes the detection location. This class of event typically generates maximum fluence, but in this case, the flux and fluence will not scale in the classical manner with radial distance.     

Ray Based Diffraction Tomography of the Ionosphere and Laboratory Inhomogeneous Plasma

A new procedure for restoration of the plasma inhomogeneities with improved resolution is suggested. The procedure deals with the double weighted Fourier transform (DWFT) of the observed wavefield in coordinates of both receivers = (x, y) and sources ₀ = (x ₀, y ₀) [1]. Phase increments between the sources and receivers, being found from DWFT representation, can be used for extracting information on small perturbations of the dielectric constant ~(, z) in a way similar to traditional radio tomography. The resulting resolution of the method is close to the diffraction limit = h/D in the horizontal direction and z = (h/D)² in the vertical direction, where h is the height of inhomogeneities and D is the length of the ground-based receiving system.     

Main results and experience obtained on Mir space station and experiment program for Russian segment of ISS

This article presents main scientific and practical results obtained in course of scientific and applied research and experiments on Mir space station. Based on Mir experience, processes of research program formation for the Russian Segment of the ISS are briefly described. The major trends of activities planned in the frames of these programs as well as preliminary results of increment research programs implementation in the ISS' first missions are also presented.     

Women and couples in isolated extreme environments: applications for long-duration missions

Expedition teams provide a number of analogs relevant to crew selection for long-duration space missions. Three groups were studied that varied in team composition. Group 1 was a two woman international dyad that traversed the Antarctic continent in 97 days. Similarities in problem solving approach, respect for each other's opinions, and a collaborative process of decision making were evident. Group 2 was composed of four women, all from different countries, engaged in a six week trek across Greenland. The most important factors in overcoming interpersonal difficulties and contributing to the successful completion of the expedition were mutual respect and motivation to maintain positive and supportive relationships. Group 3 consisted of three married couples from different countries icelocked on a boat in the High Arctic for a 9 month period. The emotional support of and ability to confide in their partner were extremely important in alleviating interpersonal tensions, and contributed to the generally effective functioning of the group. Women add an element of emotional support and help to other team members that is not as evident in all-male groups. Selection of couples with strong bonds to each other is another paradigm for crew selection for extended missions.     

Lifetime total radiation risk of cosmonauts for orbital and interplanetary flights.

This paper presents results of calculations of total radiation risk for cosmonauts over their lifetimes and assessments of possible shortening of life expectancy on the basis of generalized doses calculated for cosmonauts after a long term interplanetary and orbital space missions on "MIR" station and International Space Station with the use of mathematical expressions coming from a model of change mortality rate of mammals after irradiation. Tumor risk assessments for cosmonauts over lifetime after flights are also given. Dependences of the delayed radiation consequences mentioned above on flight duration, spacecraft shielding thicknesses, solar activity and cosmonauts' age are analyzed.