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This article characterizes the spacecraft as a means of performing various tasks, including by precision equipment. Emphasis is placed on vibration as one of the influencing factors and on the need for a low level of vibration on the spacecraft. Among the side effects of the electric pump unit of the thermal control system, the urgent task is to reduce vibration activity when developing a new model for advanced spacecraft. An integrated approach to solving the problem is indicated with the consideration of electric pump unit as a system and the selection of several directions to achieve the root-mean square value of vibration acceleration of 0,01g and below. Possible methods for reducing vibration activity in each of the directions and implemented solutions in the developed sample are described in detail. On several versions of electric pump unit for experimental determination of the level of root-mean square value vibration acceleration at a frequency of 5–1000 Hz. According to the results of the experiment, the contribution to the reduction of vibroactivity in several directions is estimated. It is concluded that only an integrated approach makes it possible to achieve a very low level of vibration activity of electric pump unit.

The paper reports a brief description of spacecraft operating conditions, the main reasons of heating and thermal gradient appearance and need to reassign the thermal energy. Active thermal control systems and their advantages are considered, spacecraft for which the use of this type of thermal control systems is a priority. The electric pumping unit is pointed as a key unit of active thermal control systems. The electric pump unit is considered from the as the electromechanical system, its key elements are pointed. A description of the preferred pump types is reported and the types of active thermal control systems are briefly discussed. The foreign and domestic operating experience of spacecraft electric pumping units, the features of their designs are considered, the most common types of key elements are determined. Based on the results of the review, it is concluded that the most relevant layout of the electric pump unit is a centrifugal electrical pump with a brushless DC motor and hydrodynamic bearings. It is also indicated that the electric pump unit is a product with a long lifetime, which complicates the task of monitoring the technical condition in order to prevent failure.

This paper presents the methodology and test results of rolling bearings of low-flow electric pump units used to ensure circulation of the thermal liquid in the active thermal control system of spacecraft. A multi-position stand has been developed for testing bearings within 40 days in a thermal liquid at a speed of 6000 rpm with the possibility of registering the separator rate speed. As a performance criterion, the clearance in the bearing is used. The conditions of the onset of pitting are investigated.

The work is devoted to the protection of a spacecraft from the influence of unacceptable internal vibration sources. The urgency of reducing the vibration activity on board the spacecraft to improve the accuracy of the target equipment is indicated. A particular problem of vibration protection of the spacecraft platform from a vibration source – an electric pump unit of a liquid thermal control system – is being solved. The basic requirements for electric pump unit vibration protection have been determined. Possible ways to reduce the level of vibration excited by the electric pump unit on the surface of the spacecraft fixation are considered. Particular attention is paid to such vibration protection methods as damping and vibration isolation, implemented by installing special vibration protection devices between the source (electric pump unit) and the object (spacecraft) – vibration isolators and vibration dampers. The principles of operation of vibration dampers and vibration isolators, the most common materials for vibration dampers are described. Examples of constructive solutions for linear single-axial vibration isolators are considered, recommendations for the use of promising products are developed. Particularemphasis is placed on the use of metal rubber as a material for vibration isolators. With regard to a specific design of electric pump unit, a diagram of the spatial structure of vibration isolation is proposed. Formulas for calculation are given in detail, a mathematical model of the vibration isolation system is developed. The procedure for calculating the parameters of the system has been formed. Based on the model, the maximum possible level of vibration suppression in the mid-frequency region was determined. Minimum required number of operable pixels was identified for monitoring the water surface with sufficient accuracy and reliability.