Annotation: This article considers the problem of determination of propulsion system solid fuel burn-out time in the extraatmospheric flight segment taking the apparent acceleration and apparent speed measured by the inertial navigation system. Correlation analysis of the realized and nominal dependencies of the apparent acceleration and apparent speed of the launch vehicle on relative operating time of the propulsion system is suggested to be used to forecast the fuel burn-out time. In order to improve the accuracy of the forecast, and to decrease the amplitude and vibration rate of its results several channels simultaneously are suggested to be used for calculations with subsequent majority voting and digital filtration. As a result of the study, the procedure to forecast the time of solid fuel burn-out in the launch vehicle propulsion system in flight has been developed. Operability of the suggested procedure has been verified using the mathematical simulation of the launch vehicle flight for two operating modes of the propulsion system different from the nominal ones. Based on the statistical processing of the deviations of the predicted time of solid fuel burn-out versus the realized one it was determined that the forecast based on the results of apparent acceleration measurement has the greatest accuracy with the minimal number of operations. Suggested procedure is easily realized as the multistage adaptive algorithm and can be used in the guidance system of the solid-propellant launch vehicle in the extra-atmospheric flight segment for the numerical forecast of the reachable terminal parameters of flight, definition of command vector and development of the relevant thrust vector control commands.

Annotation: The general information on gas pressure reducers, on their purpose in launch vehicles and spacecraft pneumohydraulic systems is set forth. The impact of different operating conditions on physical characteristics of these devices is considered. The main and auxiliary parametric characteristics of the reducer are presented and the physical process of gas pressure reduction in it is explained. The error of output pressure regulation is evaluated using full differential of function, whose arguments (input pressure, flow rate, temperature) have scatter. The reducer temperature curve is shown and the impact of structural temperature on the value of dynamic (with flow rate) and static (without flow rate) pressure in reducer output cavity is explained. The difference between the excess pressure reducer and absolute pressure reducer is shown. The brief review of the designs of liquid and bimetal thermal compensators is presented, their advantages and disadvantages are described and the experience of reducers testing with regulating springs made of elinvar is analyzed. Attention is focused on operating temperature and its impact on stability of reducer adjustment. The formulas that describe thermodynamic processes occurring in the reducer are presented. Special attention is given to the properties of regulating spring of the reducer because of change of elasticity modulus coefficient at different temperatures, the expected pressure scatter at reducer output is evaluated and the necessity of measures to reduce this error is explained. To compensate for temperature disturbance, the formula of gas pressure in closed volume of sensitive element is derived. The essence of original technique of pneumocorrection of initial pressure in sensitive element cavity that was proposed and introduced on Yuzhnoye SDO-developed reducers is set forth.