First experience to clean the external surface of the spacecraft window panel

The technological operation for cleaning the window panel external surface of the Service Module being part of the Russian Segment of the International Space Station is presented. The work was prepared by specialists of S.P. Korolev Rocket and Space Public Corporation Energia and for the first time in practice of manned spacecraft operation was performed during extravehicular activity on August 10, 2015 by cosmonauts Gennady Padalka and Mikhail Kornienko. The article underlines the importance of cleanliness of the mentioned window panels for their intended use, the examples of their actual state are given, some assumptions about the sources and causes of pollution are stated, the urgency of this problem is substantiated and the approach to its solution is shown including demonstration of the capability of mechanical removal of the fine dust layer in the scope of space experiment Test. The cleaning device is shown, the description of manipulations and actions of cosmonauts during extravehicular activity is given. Preliminary data on the composition of the refinement products which were returned to Earth and subjected to physicochemical analysis is obtained as an additional result of these activities. Research will be continued in the interests of rationalizing the treatment technology and dust prevention.