Long-term biological investigations in space

Missions in space within the next two decades will be of longer duration than those carried out up to the present time, and the effects of such long-term flights on biological organisms are unknown. Results of biological experiments that have been performed to date cannot be extrapolated to results in future flights because of the unknown influence of adaptation over a long period of time. Prior experiments with Axolotl, fishes, and vertebrates by our research team (in part with sounding rockets) showed that these specimens did not appear to be suitable for long-term missions on which minimization of expense, technique, and energy is required. Subsequent investigations have shown the suitability of the leech (Hirudo medicinalis), which consumes blood of mammals up to ten times its own weight (1 g) and can live more than 2 years without further food supply. Emphasis in the experiments with Hirudo medicinalis is placed on metabolic rhythm and motility. Resorption and diffusion in tissue, development, and growth under long-term effects of cosmic proton radiation and zero-gravity are other focal points. The constancy of cellular life in the mature animals is a point in favor of these specimens. We have also taken into account the synergistic effects of the space environment on the problems just mentioned. The life-support system constructed for the leech has been tested successfully in four sounding rocket flights and, on that basis, has been prepared for a long-term mission. Long-term investigations out of the terrestrial biosphere will provide us with information concerning the degree of adaptation of certain physiological and biochemical functions and as to what extent biological readjustment or repair processes can occur under the specific stress conditions of space flight.     

THE INFLUENCE OF THE LOCAL INTERSTELLAR MEDIUM ON THE SOLAR WIND DYNAMICS IN THE INNER HELIOSPHERE

The consequences of the interaction between the solar wind and the local interstellar medium for the wind region enclosed by the heliospheric shock are reviewed. After identifying the principal mechanisms to influence the dynamics of the solar wind, an approach allowing the simultaneous incorporation of neutral atoms, pick-up ions, cosmic rays and energetic electrons into a multifluid model of the expanding wind plasma is outlined. The effects of these particle species are discussed in detail, with special emphasis on the electron component which behaves more like a quasi-static hot gas rather than an expanding fluid. This electron gas is effectively trapped within a three-dimensional trough of a circumsolar electric potential whose outer fringes are possibly determined by the density distribution of anomalous cosmic rays. The electrons are proven to be a globally structered component of great importance for the solar wind momentum flow contributing to a triggering of the solar wind dynamics by asymmetric interstellar boundary conditions. Finally, the consequences for the relative motion of the Sun and the local interstellar medium as well as for the solar system as a whole are described.     

Present day challenges in understanding the geomagnetic hazard to national power grids

Power grids and pipeline networks at all latitudes are known to be at risk from the natural hazard of geomagnetically induced currents. At a recent workshop in South Africa, UK and South African scientists and engineers discussed the current understanding of this hazard, as it affects major power systems in Europe and Africa. They also summarised, to better inform the public and industry, what can be said with some certainty about the hazard and what research is yet required to develop useful tools for geomagnetic hazard mitigation.     

Novel active driven drop tower facility for microgravity experiments investigating production technologies on the example of substrate-free additive manufacturing

Through the striving of humanity into space, new production processes and technologies for the use under microgravity will be essential in the future. Production of objects in space demands for new processes, like additive manufacturing. This paper presents the concept and the realization for a new machine to investigate microgravity production processes on earth. The machine is based on linear long stator drives and a vacuum chamber carrying up to 1000?kg. For the first time high repetition rate and associated low experimental costs can provide basic research. The paper also introduces the substrate-free additive manufacturing as a future research topic and one of our primary application.