Problems and the outlook for the development of effective systems of controlling the thermal regimes of spacecraft are considered. The process of creating and using the apparatus of mathematical modeling for the purpose of comparing the energy characteristics of different systems is described. The characteristics of forward and reverse working cycles of two-phase closed systems that control the thermal regimes are compared.A thermal regime control system is intended for creating and maintaining specifi ed temperatures onboard a spacecraft in the course of its active existence. The basic sources of heat input into a spacecraft are understood as either external (thermal radiation of the Sun and other celestial bodies) or internal (thermal release from working devices and electronic equipment). The temperature of the devices must be maintained at a specifi ed level (for most types of equipment 0-40°C [1]) through discharge of heat fl ows into space in order to assure stable operation of the equipment on the spacecraft. A thermal regime control system on which stringent requirements are imposed [2] is used for this purpose.Possible alternative confi gurations of the thermal regime control system are distinguished by the trend along which the thermodynamic process is realized, the principles for the transmission of heat, and the incorporation of different functional elements in the circuit. The design of rational systems includes constructive optimization of the thermal regime control system, hence it is necessary to create an effective computational model.The ANSYS, Thermica, ESATAN-TMS, SINDA, Radsol, and other program packages [3] that are now used for such calculations suffer from a number of drawbacks, including high commercial cost, the fact that it is not always possible to integrate the systems with external applications (for example, with databases of the properties of the working media), the fact that it is not possible to take into account the hydraulic features of the circuit in the course of optimization and modeling, and the considerable time needed to perform the calculations for given boundary and initial conditions. It is therefore necessary to develop mathematical models that correspond to the above requirements and that are designed to compare the energy characteristics of different types of thermal regime control systems used on spacecraft.Closed two-phase thermal regime control systems that are widely used and employed (in different structural variants) on most spacecraft [4-6] will be considered in the modeling process.

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The paper presents an analysis of the design features of turbines for low-power electricity generation systems (up to 10 kW). The specifics of the working process of this type of turbines is described. The basic requirements for the design are presented. The description of the stand for experimental research is given. The obtained experimental results are presented.