Orbital space telescope is a complex and expensive system. Electro-flywheel systems are used on such spacecraft as the orientation and stabilization system actuators making it possible to ensure the required accuracy of pointing an orbiting space telescope to a given region in the outer space. This paper considers the situation of failure of one of the flywheels on a spacecraft of the Hubble Space Telescope type. An algorithm for the orientation and stabilization system operation in such emergency was developed making it possible to ensure rotation of the spacecraft by a given angle with the remaining three controls functioning and without reducing the telescope pointing accuracy. A spacecraft model was created in the Simulink (MATLAB) dynamic simulation environment to develop this algorithm.
The purpose of the work was to experimentally research and analyze the effect of the proposed modifications of a pneumatic bullet on the accuracy parameters of the shooting system with a subsonic initial speed. The study introduces variants of modernization of a bullet with a flat head part for pneumatic weapons, describes the external ballistic experiments carried out on the ballistic track of the Department of Dynamics and Flight Control of Rockets and Spacecraft of Bauman Moscow State Technical University, and theoretically substantiates the physics of the interaction between a bullet and the air, which became possible after analyzing the results of shooting. The obtained correlation between scattering characteristics of unguided aircraft and the type of modification of their aerodynamic shape is described. On the basis of the data obtained, modifications of the bullet shape were determined, leading not only to a decrease in aerodynamic drag, but also to a certain decrease in dispersion during shooting.
The article considers a technique for constructing an optimal guidance procedure for an aerospace aircraft. The technique is based on the adaptation of the Pontryagin maximum principle for the considered class of problems. At the same time the guidance accuracy is ensured by solving a boundary value problem, which is periodically performed during the flight. The developed procedure for predicting the final parameters of the optimal flight according to a simplified motion model is presented, which also makes it possible to determine the value of the actual miss. A detailed mathematical description of the proposed technique is given. The feasibility of the proposed technique is ensured by minimizing the amount of computational operations. The guidance algorithm efficiency is illustrated by a numerical example with a flight simulation procedure taking into account all significant factors. The paper also provides examples of solving boundary value problems and the results of modeling the optimal guidance.
The purpose of the study was to carry out a numerical simulation in a special package of the subsonic air flow around a pneumatic bullet of various modifications, the latter being previously experimentally tested on the ballistic track of the Department of Dynamics and Flight Control of Rockets and Spacecraft at Bauman Moscow State Technical University. The paper briefly analyzes the applicability of the most common computing packages for solving the problem, justifies the use of the ANSYS CFX package, describes the requirements and features of the computational grid construction, and gives the boundary conditions. The verification problem was solved, which showed good correspondence of the constructed model to the results of field shooting carried out in previous studies. The influence of the longitudinal rotation of the reference model of the bullet on the pattern of its flow and aerodynamic characteristics were investigated. The results of the calculations confirmed the drag improvement and bullet dispersion effects obtained when testing a number of modified samples. The calculated flow patterns and pressure fields contributed to a complete understanding of the physics of the studied modifications in a wide range of flight speeds.
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