ANGULAR MOVEMENT PROGRAM CALCULATION PROCEDURE SPACECRAFT WHEN TAKING THE SURFACE OF THE EARTH IN AREA MODE

Currently increased interest in satellite images of the Earth's surface with high resolution terrain (1 to 10 m). To obtain such images, you must use a long focus optical system (OS) having a limited field of view that does not allow the images of the large width. To increase the effectiveness of shooting in modern space systems (SS) Earth observation provides the opportunity after shooting a segment of the Earth's surface to redirect the OS to another area and spend it shooting. With sufficient speed shift OS it is possible to survey two or more adjacent parcels, which is almost equivalent to the corresponding increase in the width of the field of view of the removing apparatus. In this connection there is the task of restoring the OS, which is solved by the use of appropriate hardware and software control the angular movement of the removing apparatus. When creating the SS there is also the need to solve the following tasks: calculation of the program angular motion in a given length of the removable sections and a predetermined number of adjacent strips to be shot, with the purpose of definition of system requirements, spacecraft (SC) control and calculation under given characteristics of the system orientation of the SC possible number of the maximum length and remove adjacent portions of the surface of the Earth. To solve these tasks the mathematical model software of angular motion of the SC. Given the necessary initial data, mathematical model and method of calculation of kinematic parameters of a software angular motion of a SC in the mode of area highway shooting adjacent sections of the Earth's surface located at a predetermined distance from a trace route SC; examples and results of numerical calculations of the programmes angular motion by moving the instrument in remote sensing.

CONTROL WITH REDUCING OF DISTURBING FACTORS

The structural and dynamic features of the space (moving outside the dense layers of the atmosphere) stages of rockets - carriers of spacecraft as control objects are analyzed. The reasons are investigated - disturbing factors that generate external forces and moments that determine the disturbed motion of space rocket stages. For space rocket stages, disturbing factors are: mass asymmetry of the stage relative to its longitudinal axis and angle of mismatch of the line of action of the thrust vector of the propulsion system of the stage with the longitudinal axis of the stage. It is shown that when using the stage control deviating in the hinge of the marching engine as the executive organs of the control system, the effect of auto-reduction of the mentioned disturbing factors arises. The consequence of the autocompensation of disturbing factors is the reduction of disturbing forces and moments that violate the programmed motion of the step in the pitch and yaw planes. Mass asymmetry and the angle of mismatch of the line of action of the thrust vector of its engine and the longitudinal axis of magnitude are constant. Therefore, a decrease in perturbing forces and moments is accompanied by a decrease in the amount of energy (fuel) spent on processing (zeroing) perturbations of the parameters of the perturbed motion of the stage. It is shown that if the thrust of a space-stage engine is 8000 kgf, the engine operating time (flight time of the stage) is 500 sec, the specific engine thrust is 330 sec, the mass asymmetry is 0.05 m, the angle of mismatch is 0.25 degrees, then fuel economy can reach 200 kgf. The studies were performed using mathematical modeling methods.

THE ISSUES OF CHEMISTRY AND TECHNOLOGIES OF RESIN MIXTURES FABRICATION FOR INTERNAL HEAT-PROTECTIVE COATING OF ROCKET SOLID FUEL ENGINE

One of specific features of rocket engineering – is the high rate of sophistication and renewal of structures due to constantly growing operational and technical specifications imposed to them. Every generation of rocket and space products features a new complex of design and processing parameters and new materials possessing higher properties. It is impossible to resolve the entire scope of design and processing tasks in course of development, creation and operation of spacecraft without extend development and infusion of new materials which possess a number of required characteristics imposed to state-of-the-art technology products. The most widespread and sophisticated structures of modern technology – are solid-propellant rocket motors (SPRM) made of polymer composite materials. One of the major tasks associated with their creation is development of the internal thermal protection coating of solid-propellant rocket motor casing. State enterprise Yuzhnoye Design Office named after M.K. Yangel is currently carrying out works on creation of solid-propellant rocket motors. Development of their internal thermal protection coatings using mainly domestically produced materials with specified requirements is a scientific and technological task of high importance which confirms the relevance of dissertational research.The article is devoted to the analysis of components and ingredients for rubber compounds, which provide the properties and basic functions of the thermal protective covering of solid propellant rocket engine. The article shows the main results of the work related to the development of prescribed composition and technology of manufacturing of elastomeric material which used in the manufacture of internal heat-resistant coating of solid-propellant rocket engines made of polymer composite materials.

DEVELOPING AND CREATION OF GROUND TESTING SIMULATOR FOR ORIENTATION AND STABILIZATION SYSTEM OF POLYITAN NANOSATELLITES

The article under the heading "Developing and creation of ground testing simulator for orientation and stabilization system of PolyITAN nanosatellites" is devoted to the research of methods of developing of the specialized simulator for the nanosatellite orientation and stabilization system ground testing. This problem is showed on the example of simulator developed in the National Technical Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”. Ground testing of the orientation and stabilization system is critically important phase of the pre-flight preparation of the nanosatellite. In order to provide precise tests, the simulator described in this article was developed. Objective of the simulator is to create targeted magnetic field in assured volume, where flight of the nanosatellite is imitated, stabilization and orientation performances are tested. The introduction describes experience of the PolyITAN team in developing of nanosatellites, the tasks of the first two nanosatellites - PolyITAN-1 and PolyITAN-2 are revealed, the actuality of this research is highlighted. The main part reveals the order of development of the simulator for orientation and stabilization system ground testing in gradual and sector-wise way. First part shows construction decisions in the simulator’s configuration to ensure accomplishment of the simulator’s objective. Second part describes calculation of the number of turns and the diameter of the wire to provide required value of the modulus of the vector of magnetic field induction, which is created by the simulator. Next part is devoted to calculation of power required for power sources, increment of magnetic field induction as a function of the current increment is provided, what is very important for power source selection. Next part is a research of the uniformity sphere - working space of the simulator, which must provide enough volume for testing of the 3U nanosatellites of CubeSat format. Final part describes control system of the simulator.

PROSPECTS OF ANISOGRID LATTICE STRUCTURES USING IN ADAPTERS OF LAUNCH VEHICLE

The efficiency of using anisogrid lattice structures in launch vehicle designs, in particular in payload adapters, is investigated. On a specific example of the design of the adapter, which is in operation, it is compared with an anisogrid adapter, which is made of different materials - composite, made by winding, and metal using additive technologies. The performance of the adapter was evaluated by the criterion of minimum mass, subject to the requirements of strength and stability. The initial geometric parameters of the anisogrid lattice structure were determined under the condition that the critical stresses are equal for the symmetric and asymmetric cases of stability loss for the structural orthotropic shell model. Calculations and comparisons were made for composite materials - fiberglass, carbon fiber, organoplastic and boraluminium, as well as metal - AMG6M, BT20. Checking the geometrical parameters calculated on the model of structural orthotropic shell showed that they do not meet the requirements of strength and stability. The choice of geometric parameters of a working adapter design is made by numerical experiment with finite element method. The geometry of the lattice structure of the adapter was parameterized to ensure the variability of two geometric dimensions of the cross section of the longitudinal rib and two geometric dimensions of the cross section of the upper frame. The numerical experiment was performed for the constructions made of carbon plastic and for metals AMG6M, BT20. The results of the calculations showed that the anisogrid lattice structures give a gain on the weight of the adapters, which is up to 50% compared to the designs in operation.

EVALUATION OF THE RELIABILITY TEST RESULTS OF A ROCKET ENGINE BASED ON A LOGICAL-PROBABILISTIC METHOD

A logical-probabilistic method for evaluating the test result is proposed, which is based on the theory of evidence of Dempster-Schafer with some assumptions that do not affect the final result. Currently, there is an acute question of creating new types of rocket technology in connection with a change in the situation on the international and domestic market. When creating new samples, it is necessary to pay special attention to the level of their reliability, but also remember to take into account the financial component of projects for the development and manufacture of products. In this regard, research is currently being conducted not only in the direction of increasing the reliability of complex technical systems, which include rocket engines, but also in reducing the cost of their refinement. One of the research options in this direction was proposed by the author in this work. The aim of the work and research as a whole was to demonstrate the capabilities of the chosen method for evaluating the test results, according to which it would be possible to draw conclusions about the success of the tests themselves. As studies have shown, the logical-probabilistic method for evaluating test results based on the Dempster-Schafer theory of evidence, due to the lack of a priori information, can be used in the development of new rocket engine models, but only in a narrow direction. More widely, this method can be used in the design of products based on accumulated experience (amount of information) on existing analogues. Dempster-Schafer proof theory can be applied at earlier design stages, but only in combination with other reliability models.

SYNTHESIS OF AN ADAPTIVE AUTOMATIC SYSTEM OF AIRCRAFT CONTROLS WITH MULTIDIMENSIONAL PI-REGULATOR

The article presents the synthesis of a functional diagram of an adaptive automatic control system (ACS) for controlling an aircraft with an automatically reconfigurable multidimensional PI controller, which provides the minimum static and minimum mean square error of control with minimal energy consumption for the formation of the control exposure. The synthesis of ACS algorithms is performed as a result of solving the problem of conditionally minimizing the quadratic functional of the generalized work (taking into account restrictions on state variables and control actions given by differential equations of the control object (CO) and inequalities). The mathematical description of the multidimensional CO is carried out using the CO model in the state space, which automatically takes into account the mutual influence of individual control loops on each other. As the state variables of the aircraft, linear displacements, speeds and accelerations of the center of mass of the aircraft, and angular displacements, speeds and accelerations of the rotational movement of the aircraft relative to the center of mass are used. The matrix equation of dynamics of the aircraft is formed by a system of nonlinear differential equations of the first order of forces and moments of forces acting on the aircraft. To ensure the minimum static control error, integrators are included in the ACS (for each control action). The algorithm for the formation of control actions of the extended CO, providing the declared properties of the ACS, is obtained as a result of solving the problem of conditional minimization of the generalized work functional. The task of conditional minimization of a functional with constraints is performed by the maximum principle. The resulting two-point boundary value problem is transformed by the invariant immersion method into a Cauchy problem for optimal values of state variables. The evaluation of the characteristics of a specific adaptive ACS for the spacecraft is expected to be obtained as a result of further research by mathematical modeling.

YUZHNOYE`S POSITION IN WORLD PLANS FOR MOON EXPLORATION

The article discusses the lunar programs of leading countries of the world: EU, India, People’s Republic of China, South Korea, Israel, Russian Federation, Japan, USA, as well as possible direction of cooperation between Ukrainian cooperation and mentioned countries. The US lunar program is the most attractive. NASA invites private companies which can become Yuzhnoye State Design Office partners. Perspective payload delivery means into lunar orbit are proposed: Space Launch System, Falcon Heavy, Straship. Marketing strategy was developed to achieve economic efficiency of the space launch system operation project, designed for payloads injection into the lunar orbit (with Mayak launch vehicle family, developed by Yuzhnoye State Design Office, as an example) due to covering all possible segments of commercial, as well as government launch market. At the same time, comparison of price and performance characteristics of space transportation services into low Earth orbit is shown as of 2019. The prospective demand for Mayak launch vehicle family within the framework of the US state program for the development of the Moon was determined. According to the results of the marketing research, it can be concluded that with the price of about 3 000 US dollars for launching 1 kg of payload into low Earth orbit (from 70 to 330 million US dollars for launch), Mayak launch vehicle family have the advantageous position on the launch market into low Earth orbit and lunar orbit in comparison with the competitive positions of other ILVs in this market segment.

GROUND-BASED EXPERIMENTAL TESTING OF ELEMENTS OF AUTOMATION OF PNEUMATIC-HYDRAULIC SYSTEMS OF ROCKET AND SPACE TECHNOLOGY

The design and production of sophisticated technical systems, which include modern rockets and other aircraft, requires their reliability and trouble-free operation. To achieve the required level of reliability of aerospace products, a wide variety of test methods are applied at all stages of the life cycle. One of the most important systems of the launch vehicle is the pneumatic hydraulic power system of the liquid rocket propulsion system. Development of new and improvement of existing methods of control and diagnostics is one way of increasing the design and technological reliability of products of aviation and space technology. The use of functional diagnostics systems for bench and flight tests significantly increases the reliability and efficiency of space rocket technology. Researches are directed on increase of a level of reliability of products of aerospace branch. Application of systems of functional diagnostics is described at bench tests. The results of experimental researches of elements of automatics of pneumatic hydraulic power supply systems of liquid rocket engines are considered. The technique of processing of experimental data of a pulsing-acoustic method of diagnostics with use of the mathematical technology of recognition of images is presented. Deciding rules of recognition of a technical condition of object of diagnosing by results of tests are resulted. The developed method with a high degree of accuracy allows to determine the technical condition of the object of diagnosis as defective or to detect the presence of characteristic defects. Experimental testing and the proposed method of processing the results showed the efficiency of the method.

MATHEMATICAL MODEL FOR SOLVING THE NAVIGATION PROBLEM AND ANGULAR ORIENTATION SPACECRAFT

Currently, there is an increased interest in the creation of strapdown inertial navigation systems (SINS), which make up the information core of modern airborne systems for the orientation and navigation of spacecraft (SC). An urgent problem arises, which is associated with the development of high-precision algorithms for estimating and filtering data from the sensors of the SC motion parameters, the mathematical model of the SINS, calculating its errors and analyzing the effect of errors on the characteristics of the navigation system and orientation of the SC. A mathematical model is proposed for solving the problem of navigation and angular orientation of a small SC equipped with electromagnetic control elements, taking into account the filtering of “noisy” magnetometer data. The requirements are set for the accuracy of the angular orientation and stabilization of the SC in the mode of maintaining the triaxial orientation of the SC in the orbital coordinate system (OCS) and for the duration of the damping mode of the angular velocities obtained by the SC during separation from the launch vehicle (LV), and the mode of the initial construction of the triaxial orientation of the SC in OCS. The mathematical model includes: a model of the motion of the center of mass of the SC in the osculating elements of the orbit with specified parameters, a model of the angular motion of the SC around the center of mass, a model of the Earth’s magnetic field (EMF) and a model of filtering magnetometer data. As an arithm for filtering data from a magnetometer on the components of the magnetic induction vector of the EMF, a one-parameter algorithm of exponential smoothing (exponential moving average) is used, which belongs to the class of first-order filters with an infinite impulse response. The results of numerical simulation of the dynamic processes of navigation and the angular orientation of the SC after separation from the LV taking into account the filtering of magnetometer data by the method of exponential smoothing using mathematical models are presented, and the accuracy of the angular orientation and stabilization of the SC is estimated.