About the IAA event

This was the Sixth Symposium having continued the discussions launched during the preceding Symposia, which also resulted in special sections or special issues of collected papers published in Acta Astronautica.

The Symposium participants discussed the Moon exploration program and relevant safety aspects. Academician Mikhail Marov delivered a lecture on the concept of the Russian moon exploration strategy. Space debris flux estimation of take-off trajectories to the Moon was discussed in the paper lecture by A.I. Nazarenko, I.V. Usovik. Basic concepts of spacecraft shielding development were discussed in the plenary lecture by N.N. Smirnov, A.B. Kiselev, P.P. Zakharov. Experimental investigation of hyper-velocity collision between aluminum projectile and protective shielding found coverage in the plenary lecture by A.I. Kozachuk, A.I. Mikhailin, B.V. Rumyantsev, M.V. Silnikov representing a joint team of the Institute of Physics and Technology named after A.F. Ioffe, Russian Academy of Sciences and Scientific and Production Enterprise «Special Materials Corp». Studies on Space debris hazards and analyzing space debris accumulation and its impact on technological, social and political aspects were essentially broadened by including topics of shielding, hypervelocity impact, experimental and theoretical modeling of hypervelocity launch systems, such as light gas guns, formation of compact elements in explosion and studying impact dynamics on shields of different structures. Mechanical properties of energy-absorbing structures of relaxation type were discussed during the session. The problem of eliminating hazards of uncontrolled re-entry of satellite parts after finishing their mission in Low Earth Orbits was discussed. New methods for prediction of re-entry of large Space objects and their motion in the atmosphere were reported, which happened to be more precise then the existing ones. The problem of active Space debris removal was discussed. In particular, Space tether systems used for active debris removal from the orbits were discussed. It was emphasized, that despite using these system being very effective, there exist some inherent problems of stability of deployed tethers while a mass is sliding along it being affected by gravity, inertial and Coriolis forces. It was demonstrated, that active affecting the tether attachment point could essentially decrease the oscillations and suppress the instability. Wave processes in the cable of the Space tether system were analyzed in the presentation by P.A. Dyakov - a young scientist from Federal Science Center "Scientific Research Institute for System Analysis of the Russian Academy of Sciences". Study on small space debris hazard assessment for space activities and Earth ecology was reported by D.Yu. Ubozhenko, A.G. Aver'yanova from Central Research Institute of Aerospace Defense Forces. Protection of Space structures from space debris collisions and micrometeoroids was discussed in the presentation by Sangchul Lee from Korea Aerospace University. Interaction of compact space debris clouds in Earth orbits and libration points was discussed in the presentation by T.V. Salnikova from Moscow M.V. Lomonosov State University. Theory of hierarchical multilevel systems was applied for developing strategies of Spaceport ground-based infrastructure formation and operation was discussed in a plenary lecture by I.V. Barmin, V.N. Neustroyev, A.V. Okhlopkov representing Russian Space Agency and Russian Academy of Cosmonautics named after K.E. Tsiolkovsky. The principles of ensuring ground-based safety were formulated. A generalized indicator of safety in terms of the "Ground based Support Infrastructure – Integrated Launch Vehicles" system was proposed and its implementation was analyzed. Some new technological solutions and rescue equipment were presented. The safety concepts for manned launches were formulated and analyzed. Until now only three countries - Russia, United States, and P.R.China - have carried out the manned launches. In addition to the manned Space programs adopted by these three countries the European Space Agency (ESA), India, Japan and other countries are on the way to carry out the manned launches as well. The priority tasks of the further outer space exploration are focused now on study of Moon. The position of the leading space states of the world is formulated placing the priority on studying the Moon and, probably, more distant objects as well. That makes the problem of ensuring safety of Ground based Support Infrastructure interaction with Integrated Launch Vehicles for manned flights very acute. Other presentations on the topic analyzed different optional launch malfunctions. Destruction of fused silica by intense laser radiation was reported in the lecture by A.D. Kiverin, V.P. Efremov representing Joint Institute for High Temperatures of Russian Academy of Sciences. S. N. Kosinov, V. F. Nikitin, V. V. Tyurenkova, M. N. Smirnova representing a joint team from Moscow M.V. Lomonosov State University and Federal Science Center «Scientific Research Institute for System Analysis of Russian Academy of Sciences» analyzed conductive screen protecting from electromagnetic high-frequency radiation in Space in the presentation. The effect of Space radiation on flight programs safety were widely discussed in the recent years. The problem of Space flight safety relies heavily on the reliability of on-board electronic devices and their protection from radiation effects. A high-frequency electromagnetic field affecting on electronic equipment can bring to damages in it up to complete destruction. Usually a layer of some conductive material serves as a protector from the external electromagnetic field. This material blocks a stationary electric field completely, unlike a magnetic field; however, the alternating field penetrates the conductive layer resulting in an alternative electric current in it, which is a source of the electromagnetic field itself. The penetration process is gradual, it yields a diffusion law with a coefficient inverse proportional to conductibility of the material and its magnetic permeability, thus the alternating field is concentrated in a thin skin layer near the external surface of the layer. This layer depth depends on the frequency of the field, the higher frequency - the thinner is the skin layer. This effect is a basis for the protection from an external electromagnetic field, at least for small intensity and comparably high frequency. Such a protection is effective in the case when the skin layer is thinner than the protective layer (else the field penetrates inside). However, there is another factor worsening the protection, the Joule heat produced by the alternating current. First, heating of the layer material worsens its protective properties: lowers the magnetic permeability and conductivity thus expanding the skin layer. Second, heating the material above some level brings to its destruction: melting, evaporation, or another drastic loss of durability. Thus, it is necessary to estimate temperatures in the protective material. Effect of injection conditions on mixing performance for liquid rocket engines was discussed in the presentation by young scientists from Korean Space University. Combustion of fusible solid fuel in a hybrid rocket engine was discussed in the presentation by S.A. Rashkovsky, S.E. Yakush from A.Yu.Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Sciences. Problems of fire safety in space vehicles, fire spread over combustible materials surface were under discussion during this Symposium. Fire-extinguishing in an inhabited pressurized compartment of spacecraft during a flight was investigated in simulated low gravity conditions by M.V. Peganov from HEFEST group of companies. A.S. Melikhov, I.A. Bolodyan, L.T. Tanklevskiy representing a joint team from VNIIPO EMERCOM of Russia and Peter the Great St. Petersburg Politechnic University tested fire safety in a manned pressurized compartment of a spacecraft module during flight in artificial gravity mode. Small-size wetting agent fire extinguishers for quenching of burning personnel clothes, support of evacuation from launchers, test chambers and spaceships were discussed in the presentation by V.D. Zakhmatov, M.V. Chernyshov, V.A. Onov, A.V. Zotov, V.O. Bulatov representing a joint team of Saint Petersburg University of State Fire Service of EMERCOM of Russia and Baltic State Technical University named after D.F. Ustinov. A numerical study on flow and heat transfer characteristics of supersonic second throat exhaust diffuser for high altitude simulation was presented by Sang Hyeon Han from Chungnam National University, Korea. Preliminary design of low thrust LOX/methane rocket engine using electrical pump fed cycle was discussed in the presentation by Byungil Yu, Hyun-Duck Kwak, Hongjip Kim from Korea Aerospace Research Institute, Chungnam National University. Discussions on predictive modeling of combustion processes for ensuring Space program safety in terms of simulating rocket engines as well as air dynamics in habitable sections and optional fire spreading in case of emergency confirmed the necessity of massive parallel computing. Decreasing computing time is crucial for arriving at a decision timely. The necessity of trying different computing hardware and software architectures including specialized processors and co-processors was emphasized.