Авиационная и ракетно-космическая техника. Рубрика в журнале - Сибирский аэрокосмический журнал
On calculation of moment of resistance in canals of low-rate centrifugal pumps
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In our calculations we make use of the system of equations for turbulent boundary-layer pulses in projections onto the cylindrical coordinate axes. We have performed transformations and integration of equations in the presence of accepted assumptions on the flow core motion pattern and compared the theoretical results with the empirical data.
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On the concept of all electric propulsion spacecraft
Статья научная
Over the past several years the concept of the so-called “all electric propulsion spacecraft” has gained popularity among both customers and developers of geostationary (GEO) spacecraft; this issue is being actively discussed. The main advantages of the concept are the following: decreasing the mass of spacecraft and increasing its economic effi- ciency by means of pair orbital injection. There are some illustrative cases of implementation of this concept by Ameri- can, European and Russian companies. However, specialists interpret the content of the concept in different ways. That causes the problems connected to the development of the conceptual design of spacecraft. It is therefore very important to consider the concept in more detail, to compare various points of view in order to form understanding reflecting its essence the most accurately. At the same time, on the basis of the available examples, it would be feasible to analyze the advantages and disadvantages of this concept in comparison with other approaches to the construction of propulsion system of spacecraft. In the article we offer to interpret the concept as “ All electric propulsion spacecraft ”. This inter- pretation allows to understand its content unambiguously by the specialists of both Russian and Western Technical Schools. We offer to define “ All electric propulsion spacecraft ” as an apparatus that does not have in its composition an apogee engine unit that is chemically fuelled. It has to execute manoeuvres on geostationary orbit raising, orbit correc- tion and momentum wheel unloading by electrical propulsion only. We have shown that with the existing level of excel- lence of the equipment this concept does not have any advantages over the concept of separate propulsion subsystems for the correction and orientation by total mass as well as by the level of reliability.
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Статья научная
The paper is devoted to cross-section geometrical parameters optimization of thin-walled spokes of large-size, um- brella-type deployable satellite parabolic antennas with radial spokes. The spokes in the structures mentioned above must have maximal bending stiffness and minimal mass. Spokes with uniform thickness of walls both in the section and along their lengths are not optimal to achieve the maximal stiffness while keeping predetermined mass, because they have the same bending stiffness in any direction. In the given paper the authors suggest changing the shape of the spoke cross-section by using sections of different thicknesses. This would allow increasing the bending stiffness of each spoke in the perpendicular to the antenna surface direction while preserving the same mass of the complete structure. The thickness will be increased stepwise in the cross-sectional areas of the maximum distance from each other in the bend plane; in the remaining part of the section it will be reduced. The main objective of this paper is to obtain analytical dependences for assessment of the bending stiffness of the cross section of the umbrella-type antenna spoke with a stepwise change in its thickness. Formulas were obtained within the framework of the beam theory of bending. The obtained analytical dependencies were verified by numerical simulation in the finite element software Ansys. Verification of the obtained results by numerical simulation showed good convergence with theoretical conclusions. The formulas obtained in the paper make it possible to give practical recommendations for design of large deploy- able space antennas with improved parameters, namely maximum stiffness with minimum mass of the structure.
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Organization of complex testing of the spacecraft command and measuring system
Статья научная
In this article, we present the software for organization of complex testing of a spacecraft’s command and measur- ing system. The command and measuring system is responsible for communication of a spacecraft with the ground con- trol complex. The developed software is designed for the support of interaction between the automated testing complex of a spacecraft and test and control equipment of the command and measuring system. Complex tests include testing of all or a part of conjugate elements of a spacecraft, united in a single system, with simulation of regular and possible non-standard modes of operation. Complex tests of the command and measuring system are carried out using an auto- mated testing complex, the main task of which is transferring of the control commands to the test and control equipment of the command and measuring system. The automated testing complex also receives packages from the test and control equipment containing telemetric information about the state of the on-board systems of a spacecraft. During complex tests of the command and measuring system, the developed software supports the exchange of command and telemetry packages between the automated testing complex and test and control equipment. The developed software is built in the software of the test and control equipment as a subsystem for organizing of complex testing. The subsystem receives commands from the automated testing complex, identifies and sends them to the test and control equipment, in the form of a structure that is understandable to the command and measuring system. For each command, the subsystem produces a receipt of successful identification or of an error if it occurs. The subsys- tem receives telemetry from the command and measuring system, converts it in accordance with the protocols of inter- action and sends it to the automated testing complex. In addition to the command and measuring system’s telemetry, the telemetry of the test and control equipment is sent to the automated testing complex. It contains the parameters of the sensors of various equipment that are part of the hardware and software complex, as well as the parameters required for transmission channels’ settings between the test and control equipment, command and measuring system and other systems of a spacecraft. All actions occurring during the process of complex testing are recorded in the test report. All protocols of tests are saved and can be replayed.
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Статья научная
A mathematical model of the aircraft avionics thermal state describing the heat exchange of the onboard equipment housing with a honeycomb structure made of a carbon fiber composite, the process of heat transfer of the onboard equipment elements and the air is developed. The considered heat transfer process in a heterogeneous medium is de- scribed by the boundary value problem for the heat equation with boundary conditions of the third kind. To solve the direct problem of the onboard equipment housing with a honeycomb structure thermal state, the Monte- Carlo method on the basis of the probabilistic representation of the solution in the form of an expectation of the functional of the dif- fusion process is used. The inverse problem of the honeycomb structure heat exchange is solved by minimizing the func- tion of the squared residuals weighted sum using an iterative stochastic quasigradient algorithm. The developed mathematical model of the onboard equipment in the unpressurized compartment thermal state is used for optimizing the temperature and airflow of the thermal control system of the blown onboard equipment in the unpressurized com- partment of the aircraft.
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Статья научная
The statistic analysis results of cases correlation of abnormal functioning of SC with increased levels of geomagnetic activity are represented in the article. The main results of completing work package in JSC “ISS” to research negative influence of space environment on SC, and the main results of the development of the protective means and methods are described in the article.
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Procedure for evaluating the effective use range of the unified space platforms
Статья научная
In JSC “ ISS ” the task of evaluating the efficiency of using the previously developed unified platforms for the creation of a new spacecraft was solved in a more empirical way, by generalizing the reserve for existing developments and as- sessing opportunity and expediency of applying the existing reserve in the future (continuity of development). However, the methodological basis for solving this kind of problem has not been developed to this day. From this follows the con- clusion about the urgency of developing a methodology for assessing the range of effective application of the unified space platform and the need for its implementation. In this article, the methodical approach to problems of expediency of use of existing unified space platforms for creation of new space vehicles on their basis is considered. The sources of uncertainties arising in the design of space vehicles and the stages of choosing the optimal project under conditions of uncertainty are determined. This article describes such a design approach of space vehicles as a rational design. The main task of this approach is indicated. Also in the article the design parameters that determine the structural stability of the spacecraft are listed. A mathe- matical model of a spacecraft based on a unified space platform has been developed, which determines the dependence of design parameters on the characteristics of the payload. The criterion of a space vehicle optimal design based on a unified space platform, defined as the ratio of the effi- ciency index to the cost index for the creation of a spacecraft, is formed. A methodology for assessing the range of effec- tive application of unified space platforms has been developed. Approbation of the developed technique was carried out based on existing geostationary space communication apparatuses on the basis of a unified space platform ”Express-1000NT”, developed by JSC “ ISS ”. Calculated data and graphical representations of effective application ranges of the unified space platform “Express-1000NT” are presented. Based on the results of approbation, it can be concluded that the developed methodology allows to asses properly the range of effective application of unified space platforms for communication satellites in the geostationary orbit.
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Real-time carrier rocket mission control using space relay system
Статья научная
One of the purposes of the multifunctional space relay system “Luch” is telemetry provision for the timely control of launches from the “Vostochniy” spaceport. Launch vehicles and upper stage units have special high-speed and lowspeed relay user equipment for telemetry relaying using the relay system “Luch”. This article is about special programs for processing such kind of telemetry at the Mission Control Centre (MCC) of the federal state unitary enterprise "Central Research Institute for Machine Building" (TsNIIMASH) for mission launch control. These programs are the part of telemetry processing software-hardware system of the MCC. Their purpose is real-time reception, processing and depicting results of processing telemetry data from high-speed and low-speed relay user equipment. This article contains description of the telemetry structure, transmission scheme and description of telemetry reception and processing approach based on the specific characteristics of such kind of telemetry. It contains information about tasks, solved by the MCC telemetry complex for giving timely, objective and correct information about a launch process as well. Created programs, processing algorithms and representation forms of the results of telemetry processing successfully provided missions control of the launches of the spacecraft “Kanopus-V-IK”, “Meteor-M”№2-1 in 2017, “Kanopus-V” №3, 4 in 2018. We propose to use developed programs for telemetry provision of the timely control of orbital mean insertion during the next launches from the “Vostochniy” spaceport.
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Risk analysis and the elements of flight security
Статья научная
The problem of risk analysis for civil aviation airplanes is studied. We have investigated independent examples of risk analysis calculations for flight accidents.
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SibCube - проект студенческого космического аппарата СибГАУ класса CubeSat
Статья научная
Описывается студенческий проект сверхмалого космического аппарата SibCube. Определены цели (описаны образовательные и научные цели) и задачи проекта SibCube, проведен анализ физических условий и технических проблем, связанных с ресурсными ограничениями такого класса космических аппаратов. Определены направления исследований и пути решения данных проблем, а именно, тестирование новой элементной базы и технологий, в частности, бортового комплекса управления, выполненного по технологии «система-на-кристалле», и оборудования, поддерживающего телекоммуникационный стандарт Space Wire. Отработка использования новых технологий актуальна в связи с консервативностью космической промышленности. Также в Российской Федерации отмечается ограниченность отечественной элементарной базы. В наше время все чаще говорят о импортозамещении. Для такой огромной отрасли Российской Федерации, как спутникостроение и космическая область, в целом необходимость в своей собственной элементной базе очевидна. Однако необходимо также и тестирование такой базы. Разработчики космических аппаратов предпочитают использовать проверенную элементную базу, опасаясь недостаточной надежности непроверенных элементов. Представлена концепция модульной масштабируемой служебной платформы SibCube и описаны методы достижения модульности и масштабируемости, используемые на конструктивном и системотехническом уровнях.
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Статья научная
Electrical design of on-board radio-electronic equipment is an important stage in spacecraft design. High charac- teristics of printed circuit boards (PCBs) are essential for miniature units that have reliability, speed, stability of elec- trophysical parameters, electromagnetic compatibility. In order to do that, new design and technological solutions are necessary, in particular transmission lines with stable characteristics of per-unit-length delay (τ) and wave impedance (Z). One of the main lines, realized on a PCB is a microstrip line (MSL). In multi-layer PCBs it is often used with poly- gons. However, their influence on the stability of characteristics is investigated insufficiently. The purpose of the work is to investigate the dependence of τ and Z of MSL on the distance between the side grounded conductors as they are dipped in a substrate. In the TALGAT software we built a geometric model of the line cross-section and calculated (using the method of moments) the matrices (3*3) of per-unit-length coefficients of electrostatic induction taking into account the dielectric as well as ignoring it. We calculated the values for the change of distance between side conductors (s), dipped in a sub- strate, for different values of the height of the side conductors (h1). We revealed that for large values of s (unlike small ones), approaching of the side conductors to the air-substrate boundary does not increase but it decreases the value of τ. When s = 0.38 mm, the change of the value of h1 in the whole range almost doesn't change the values of τ and, therefore zero sensitivity of τ to changes of h1 is possible. Thus we can obtain the required Z value in the range from 48 to 59 Ohms by changing the value of h1. These results are obtained for particular values of the parameters of the line. However it is easy to obtain similar dependencies for other values of parameters. The results can be used to design transmission lines with stable delay un- der control of the impedance value.
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Статья научная
The elements of construction of electric propulsion system of spacecraft (SC) correction can accumulate electro- static charge due to interaction with the magnetospheric plasma. The impact of electrostatic discharges on the electri- cal circuit of the correction system can lead to failures of the transformation and control system (TCS). Particular attention is currently being paid to solving the problems related to the impact of electrostatic discharges on electric circuits of the power conditioning units, designed for power supply and control electric propulsion thrusters of space craft correction. Due to the design of the propulsion subsystem thrusters it is impossible to solve the problem of electric charge impact on TCS electric circuits through shielding these circuits. Therefore the impact of electrostatic discharges on electric circuits from the propulsion subsystem thruster is considered to be one of the factors determining the reliability and failure-free operation of TCS and, consequently, of the overall spacecraft propulsion subsystem. This problem is important today due to the following: the widespread use of electric propulsion thrusters in GEO spacecraft correction systems, the implementation of new TCS design and technical solutions suitable for spacecraft unpressurized platforms, the implementation of new electronic component base. The paper addresses the simulation means of electrostatic discharges occurring on the ceramics of the stationary plasma thruster and impacting TCS electric circuits, in particular the test equipment for generating high-voltage pulses, which allows replacing long-term and expensive tests performed on vacuum test benches. The paper contains the review of validation test results for TCS means of protection from electrostatic charge effects using high-voltage pulse generat- ing (HVPG).
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Solar thermal propulsion systems with various high-temperature power sources
Статья научная
The paper provides an overview of space thermal propulsion (STP) systems using concentrated solar energy as the main source of power. The paper considers solar thermal rocket engines of various configurations including those with afterburning of hydrogen heated in the “concentrator - absorber” system (CAS) with various oxidizers. Together with hydrogen the oxidizers form high-energy fuel compositions with a high value of ratio of components mass flow-rates which allows reducing the dimension of the CAS. The extreme dependences of the engine thrust on the specific impulse are shown for various values of the hydrogen heating temperature and the oxidizer-to-fuel ratio. The coefficients of the regression dependencies for the efficiency of a two-stage absorber and an absorber with the maximum non-isothermal heating having the highest possible energy efficiency are presented. The algorithms for calculating the main design parameters of the STP system as a part of a spacecraft (SC) are given, taking into account the ballistic parameters of the multi-turn transfer trajectory with multiple active segments applied to the STP systems having an energy-efficient non-isothermal CAS. The engine configurations with thermal heat accumulation and possible afterburning of heated hydrogen are also considered. Thermal accumulation allows accumulating energy in the solar-absorber during passive movement in the illuminated portions of the transfer orbits regardless of the lighting conditions of the apsidal orbit portions where the engine is turned on. Suitable heat-accumulating phase transition materials (HAM) such as the eutectic alloy of boron and silicon as well as refractory beryllium oxide are selected for different phases of the interorbital transfer to the geostationary Earth orbit (GEO). The main characteristics of different configurations of the STP systems in the problem of placing a spacecraft (SC) into high-energy GEO orbits are shown. A model of the SC- STP system operation is given taking into account ballistic parameters and the possibility of accumulating thermal energy. It is shown that the oxidizer-to-fuel ratio in STP systems with thermal energy storage (TES) increases with the decrease of the interorbital transfer time. The STP configurations with a two-stage TES showing a large energy-mass efficiency at moderate values of the solar concentrator accuracy parameter are considered.
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Stress analysis of solar array driver mechanism actuator of the spacecraft “Luna-Resurs-1”
Статья научная
The intrrest of spacefaring nations in the Moon has grown considerably in recent years. Russia, China, the European Space Agency, the USA and some other countries have the Lunar programs. The movement around the Moon has a number of the features caused by gravitational field of the Moon, mascons and the small period of rotation. Therefore these features need to be considerd at the design of both the space vehicle and its components. The electro- mechanical block of solar array drive mechanism (SADM) of the spacecraft “Luna-Resurs-1” for a remote research of the Moon is presented. It serves for rotation of solar batteries panels and provides orientation of the panels by active part to the Sun. The purpose of this work is the analysis of strength characteristics of the spacecraft electromechanical block of SADM in the research of the Moon. Stress analysis of the basic power elements of the design by method of final elements in the Static analysis application of a CATIA package is made. The results of the calculation confirm the lifting power of a load-carrying structure. The minimum margin of safety of the most loaded detail is equal to 1.91. The developed device considers all the features of the movement on an orbit of the Moon and can be used in the research spacecrafts when studying a terrain and structure of the Lunar surface.
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Статья научная
Solar cells based on AIIIBV materials in solar arrays are the main energy sources for most modern spacecraft. In spite of the fact that high characteristics have already been achieved, the work for improving solar cells is being continued due to the growth of energy consumption by spacecraft. One of the directions is decreasing solar radiation reflection by solar cell surface due to the deposition of antireflec- tion coating (ARC). In the article we show the results of the study of ARC (Ta2O5 / SiO2). We have presented the results of spectral and thickness calculations by special software of ARC on the triple junc- tion (InGaP / InGaAs / Ge) solar cell taking into account cell structure as well. We have performed the experiment of ARC on the glass-substrate to confirm the manufacturability of the process. ARC deposition has been made by electron-beam evaporation in vacuum. The results of investigation of spectral char- acteristics of samples obtained by a spectrophotometer confirm the uniformity of covering without relation to the sam- ple position in a machine. Spectral characteristic calculations for glass-substrate coincide with experimental data. The results of studying spectral characteristics of ARC on a solar cell demonstrate good correspondence with experimental data. The electric characteristics measured by the solar simulator (AM0) before and after the ARC cover- ing on the experimental samples show the increase of short-circuit current up to 122 mA and the rise of efficiency up to 7.5 %. We have demonstrated the results of scanning electron microscopic investigation of ARC on the different positions of solar cells.
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Testing of aluminum-silicon alloys mechanical properties on separately casted specimens
Статья обзорная
The mechanical properties of aluminum alloys before casting into moulds were determined on separately casted control specimens casted in horizontal or vertical forms. A comparison of the mechanical properties (tensile strength t, elongation 8, hardness HB) of 12-mm-diameter individually casted of AK7ch alloy control specimens and its density in the solid state (p) showed that it is necessary to use specimens casted in a horizontal mold for evaluation of castings quality. It was estimated that position of separately casted test samples in the foundry metal form influences the indicators of mechanical properties of aluminium-silicon alloys.
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The algorithm for estimating angular rate of spacecraft in survivability mode
Статья научная
The paper discusses the issue of ensuring survivability of Spacecraft (SC) in its long-term autonomous operation in space conditions for cases of critical failure of rate sensors. We presented an autonomous control loop in survivability mode in the form of a functional circuit and a mathematical model of control loop. On the spacecraft engineered by JSC ISS - Reshetnev, failures of an angular-rate sensor took place; these failures reduced a redundancy level and unfailing performance of SC; the failure of a standby angular rate sensor will lead to impossibility to use this mode. We came up with a solution to a problem of potential failures of angular rate sensors for spacecraft in operation in orbit using addi- tional control logic; this solution is the purpose of our work. We developed a mathematical model of control without using an angular rate sensor. We described the model in details and it included estimating the angular rate according to previously generated control actions, calculation of control actions and filtration of evaluation registration accord- ing to measuring of a solar sensor. We showed the purpose of each newly introduced block that gives such advantages as improving the noise immunity of control loop to measurement errors, providing search rotation in the case of failure of all rate sensors. Improved control algorithm was synthesized. Having improved the basic algorithm, we carried out ground and flight tests. We performed mathematical modeling in the environment called GNU Octave. Hybrid modeling was performed on rotary tables equipped with functional models of units and a functional model of onboard control subsystem. We conducted flight tests on real geostationary SC flying in orbit. For each test, we pro- vided description of initial conditions and presented graphs of measurement of angular rate. We carried out all the tests successfully, and the algorithm is applied on the SC engineered by JSC “ISS - Reshetnev Company”.
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Статья научная
The experimental evaluation of the working process stability with respect to acoustic oscillations in combustion chambers and gas generators of liquid rocket engines is one of the main methods used in rocket engine construction. External and internal disturbing devices using explosive hexogen often lead to the damage to the fire walls and struc- tural elements of the aggregates The disadvantages of traditional external impulse devices also include a considerable wide range of the pressure pulses values generated by them in the combustion chamber with the same value of the sam- ple of the explosive and with the constant parameters of the atmosphere in the combustion chamber, which is due to the scatter of the explosives characteristics. An alternative approach is proposed for creating a pulse effect on the working process in the combustion chamber by exploding an electrical conductor. The disturbing device is made with an explo- sive chamber connected by a channel with the reaction volume of the combustion chamber. In the electro-impulse dis- turbing device a thin wire fastened to isolated electrodes is used instead of the charge of the explosive. As a substance used to create a pressure pulse, this generator uses gas filling the blasting chamber, the mass of which depends on the pressure in the combustion chamber and in the chamber of the electro-impulse perturbative device. If one immediately heats this gas to a temperature of several thousand degrees, one can get a gas that is close in parameters to the com- bustion products of explosives in traditional external impulse devices. Such heating can be carried out by discharging through a wire of an electric capacitor charged to several thousand volts. First, instantaneous (for several microsec- onds) evaporation of the wire, and then through the plasma channel formed at the site of the wire, the final discharge of the capacitor takes place, with virtually all of the energy stored in the capacitor discharged. The plasma temperature in this case, according to different sources, can reach from several tens of thousands to one million degrees. The gas is also heated by adiabatic compression with a shock wave. The metal particles formed after the evaporation of the wire and the condensation of the vapor have a value of several nanometers and, therefore, do not damage the inner layer of the combustion chamber. The methodological bases are considered and the algorithm for estimating the stocks of stability to acoustic vibrations from the reaction of the combustion process to such pulsed artificial disturbances is developed. There have been developed electro-impulse disturbing devices that reduce the risk of damage to the compo- nents of liquid rocket engine assemblies in full-scale and model test, and have an obvious prospect for widespread use.
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The analysis of completed, ongoing and potential missions to the Jupiter system
Статья научная
In the next decade, a significant increase in the intensity of the Jupiter system and its satellites studying with the help of spacecraft is expected. The two Galilean moons - Europe and Ganymede - are particularly interesting since the potential life is possible on these objects, even in a primitive form. Such missions are being developed by ESA (“Jupiter Icy Moon Explorer” (JUICE)), NASA (“Europa Clipper” and “Europa Lander”), Roskosmos (“Laplace-P”) and others. The final goal of the European and Russian projects is the detailed study of Ganymede - the largest satellite both in the Jupiter system and in the entire Solar system. The Russian perspective project “Laplace-P” assumes the creation and launch of two spacecrafts in one launch window. At the heart of the first mission spacecraft is an orbiter. One of its tasks is mapping the surface of Ganymede from the orbit of an artificial satellite and collecting data for selecting a landing site of the second spacecraft - a landing satellite. The project should be based on the launch of a spacecraft from the Baikonur cosmodrome with the help of the Angara-A5 launcher and the KVTK upper stage. When developing the flight scheme it is assumed that in 8 years the spacecrafts should be put into the orbit around Ganymede. The flight trajectory to Jupiter is formed with the help of gravitational maneuvers near the Earth and Venus. The mission of “JUICE” involves the study of Ganymede only from the orbit of an artificial satellite. The article is devoted to comparison of completed, carried out and perspective expeditions to the Jupiter system. If the first mission - “Galileo” - was mainly focused on Jupiter itself, the future missions are aimed at investigations of its satellites. Based on the analysis of the reviewed projects, recommendations are given to improve the efficiency of the Russian “Laplace-P” project. It is established that to improve the efficiency of the Russian mission “Laplace-P” it is recommended both further structural improvement of space vehicles and the development of a trajectory in the Jupiter system based on modern methods of ballistic design.
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Статья научная
Currently, composite overwrapped pressure vessels (COPV), with high weight efficiency, are widely used in spacecraft (SC). In satellite construction COPVs provide necessary volume of working fluid for the realization of a highly efficient scheme of raising SC into geostationary orbit using standard electric propulsion engines. The issue of using such vessels in order to increase the period of active lifetime of SC and the implementation of deep-space exploration programs is relevant as well. The urgent task is to ensure the reliability of COPVs. The study of foreign literature suggests that fastening elements in direct contact with the vessel, have an important impact on the strain-stress behavior (SSB) of the vessel. The paper discusses the basic methods of fastening large-sized COPVs having a spherical shape - an adapter module is made in the form of a “skirt” and a cable-stayed system. We have created a finite element model (FEM) of COPV to analyze the effect of fastening elements on SSB of COPV. The analysis of the obtained results of the calculation shows that a cable-stayed system has almost no effect on SSB of COPV, in contrast to a composite “skirt”, which reduces the effective stresses in the place of attachment to the vessel by two times or more, causing uneven distribution of stresses. The composite “skirt” directly transfers its buckling mode to the vessel, which reflects the significant effect of the “skirt” on the vessel’s SSB. The use of a composite “skirt” in comparison with a cable-stayed system has high probability of COPV failure. The obtained results show that a cable-stayed system is more effective way to fasten COPV than a composite “skirt”.
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