Gasdynamic aspects of contamination problem on a space station

Abstract

This report focuses on the solution of contamination problem on the developing International Space Station. It was demonstrated that the orientation thrusters and the reheling systems are the main contamination sources on the station. Experimental modeling of these real gasdynamic contamination processes was maid. The new concept was formulated and new technical solutions were found aimed to reduction of the total divergence angle of contaminating fractions. This would make possible to almost completely eliminate the Contamination of the Working Module of the International Space Station. Introduction The real investigations on the orbital space station MIR and modeling experiments [1,2] revealed that operation of its orientation thrusters is accompanied with exhaust into space of burned and non-burned (including droplets) particles which go throughout almost the whole sphere (from 0 to 180" relative the jet axis). The elements of the space station being exposed to the exhaust jet of the orientation thruster undergo the mechanical, physical and chemical impact, which of are, certainly, a negative factor for them. Existence of cold surfaces (even those beyond the stream field) may cause secondary processes of condensation and makes the contamination zone even larger. The radical solution of a problem consists, probably, in refusal of orientation thrusters on chemical fuel and transition to thrusters of other type, for example, electrical on chemical neutral gases with large molecular weight xenon, krypton, argon, fulleren C60 etc. But in this case there is a problem of electrophysical effect of an exhaust plume on construction elements of orbital station. However at the present stage of development of space engineering it is quite expedient to raise the question about elimination (in a limit exception) negative influence of a plume of orientation thrusters on construction elements of orbital station. It is possible to solve this problem by limiting an angle of expansion of contaminating fractions. The engineering solution of this idea consists in the installation on an output part of the nozzle of orientation thruster of special gasdynamical protecting devices. At the same time this gasdynamical protecting devices should not change the parameters of orientation thruster, first of all thrust vector and its value (specific impulse). As far as it is known to the authors, earlier idea of use gasdynamical protecting devices for limitation of an angle of expansion of contaminating fractions and, accordingly, elimination of contamination of orbital station was not considered and was not realized. This paper is devoted mainly to the experimental solution of the shown idea. 0-7803-5729-9/99/$10.00