Application of the method of removal of space debris objects by an ion beam - the IBS method - seems to be the most effective for cleaning the GEO region. This is due to the low energy consumption ...for transfer one object in a safe orbit delta-V≃11 m/s and the possibility of removal several objects by one spacecraft. The service spacecraft for this purpose can be developed on the basis of telsat technology, taking into account its functions. Such a spacecraft should contain an ion beam injector to act on the removed object and an electric propulsion system, which serves to compensate for the ion injector thrust and to control the spacecraft motion both during transportation of the removed object and during interorbital flights. The development of a weakly diverging ion beam injector, determination of the composition and structure of an electric propulsion system, ballistics of the optimal sequence of interorbital flights, and development of an algorithm for controlling a virtual cluster: spacecraft-removed object are discussed in the article. In the majority of works on IBS, commercial ion thrusters are considered as an ion injector and engines. However, ion beams from ion thrusters have a half angle of divergence of 120-150. When propagating in outer space, the ion beam expands irresistibly due to electron thermal effects. As a result, the distance at which the spacecraft must follow the removed object during its transportation for effective impulse transmission to it should be small (estimated, about 7 m). Taking into account the dimensions of both objects and the uncontrolled movement of the removed object relative to its center of mass, the object transportation operation carries noticeable risks. The results of an experimental study of a prototype of an ion injector with an initial half angle of divergence of 20-40 are presented. The use of such an injector would provide a distance between objects of 15–20 m and reduce the risk of their collision. In connection with IBS, various aspects of spacecraft control during transportation of an object with one, two or more engines as part of the electric propulsion system are considered. In the conceptual design of the spacecraft presented in this work, the electric propulsion system contains two stationary plasma thrusters, each of which is mounted with the possibility of independent rotation respect to two mutually perpendicular directions. Spacecraft motion control, including thrust vector control, is carried out by means of the thrusters coordinated rotation. The characteristics of the spacecraft and its subsystems intended for the removal of several objects are conceptually considered. For example, parameters of the mission for the removal of up to 10 objects from the NORAD catalog from the GEO region are given. In the future, using the result obtained, the control of SC of this scheme when IBS implementing in the low-Earth orbit will be considered.
•A spacecraft (SC) for space debris objects (SDO) removal use two electric propulsion thrusters mounted on two-axis gimbals.•Experiments with an ion injector demonstrate a weakly diverging ion beam to be effective at a large distance between SC and SDO.•For stable control of the SC-SDO cluster coordinated engine turns are used.
The largest population of space debris is observed in the low-Earth-orbit region with altitudes of 600–1000 km and inclinations of 80–100°. As follows from the predictive calculations, space debris ...removal from this region exactly is of the first priority. For this reason, our article discusses the problems of controlling the motion of service spacecraft – space debris object cluster when the space debris object is removed from a low orbit with high inclination. In the conceptual design of the spacecraft presented hereinafter, the electric propulsion system contains two electric propulsion thrusters of stationary plasma thruster type, each of which is mounted with the possibility of independent rotation respect to two mutually perpendicular directions. An ion beam injector forms an ion beam with 65 mN of thrust. Spacecraft motion control, including the thrust vector control, is provided by coordinated rotation of thrusters. For such concept, a strategy and an algorithm for controlling the motion of the spacecraft center of mass are proposed, which are based on the control of the spacecraft lateral and longitudinal motion that is understood as the control of the relative distance between the spacecraft and the space debris object. The strategy of spacecraft lateral motion control assumes that due to the thrusters' rotation the spacecraft should be displaced in such a way that the vector of the relative range between the spacecraft and the space debris object coincides with the direction of the transversal of the orbital coordinate system. For the practical implementation of the control, an algorithm has been developed for controlling the thrusters' rotation to create the required values of the spacecraft acceleration projections. The mathematical model includes the equations of motion of the spacecraft center of mass taking into account the aerodynamic deceleration. The solar panels' orientation to the Sun is provided by the spacecraft roll rotation relative to its longitudinal axis and turning the solar panels relative to their axis of rotation. The change in the ion beam momentum transfer is considered using a simple simulation model. Mathematical modeling was performed for the following parameters of the initial orbit: altitude: 800 km; eccentricity: 0.0005; and inclination: 900. For the proposed control algorithm, a range of possible thrust of a single thruster was 51–60 mN. The simulation results show that the proposed control can be used to remove space debris object from low orbits with high inclination, taking into account the roll spacecraft rotation to keep the solar panels’ orientation to the Sun.
•Control a spacecraft (SC) for cleaning the LEO region from space debris objects (SDO).•The strategy of SC lateral motion control due to two electric propulsion rotation.•Solar panel (SP) orientation to the Sun providing by the SC roll rotation.•The mathematical modelling taking into account the aerodynamic deceleration.
The article deals with the integration of educational and industrial organizations. I this case we are taking into account the goals and objectives of the roadmap in the field of engineering and ...industrial design. The Russian Union of scientific and engineering public associations is an integrator of public scientific and technical organizations that are voluntary self-governing non-profit associations of scientists, engineers, teachers and teachers. The article presents the activities of RUSEA to preserve the history of science and technology, in which a large number of commemorative events have been implemented. Network structure of RUSEA, which includes the basic centers of science and technology, provides training and retraining of personnel, provides opportunities for additional education for specialists of different levels, enables the international scientific-technical conferences, seminars. round tables on topical issues of science and education.
The article considers the approach to develop of adaptive n-variant software based on versioning. The technological process is presented as a model of functionality. This article proposes approach ...based on the segmentation of versions functionality. Note that approach is aimed at increasing the unit algorithmic fullness of the version. It is shown that spatially-distributed architecture of model is formed using the proposed approach. The article presents approach to form logical functional levels that is focused on prioritization of functional tasks taking into account the system operational needs.
Low gain antenna beam forming using metamaterial Romanov, A G; Testoyedov, N A; Tutyarov, N A ...
Journal of physics. Conference series,
11/2020, Letnik:
1679, Številka:
5
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The work considers the possibility of using metamaterials to design of low-gain antennas with improved parameters of antenna pattern. It is shown that additional elements of the antenna, made of ...metamaterial, can be considered as antenna array of parasitic emitters, forming antenna pattern of the required shape. It is shown that the use of metamaterial inserts allows to optimize irradiators for reflector and lens antennas.
Abstract
The article proposes an original method for decomposition of fault-tolerant multiversion systems based on multi-attribute analysis. Decomposition into functional subsystems is carried out ...taking into account the generality of functions performed by software modules. In this work, the attribute of the importance of functions is determined based on the general function of the unmanned aerial vehicle and the set of tasks that it must perform. The division of software modules into types allows you to determine possible ways to improve reliability that are applicable to them. These are, for example, multi-version programming, recovery blocks, t/(n-1)-variant programming.
Abstract
The article presents an analysis of software and hardware technologies for information and measurement systems for environmental monitoring. The processes taking place in power plants of ...thermal power plants have different requirements for permissible emissions, which are measured using different criteria. Measuring and recording instrument data is an important part of a monitoring system. The analysis takes into account various monitoring technologies provided with a variety of tools, including up-to-date hardware and software systems. It is shown that the software and hardware technologies of monitoring systems should be implemented using real-time system software, have both hardware and software redundancy, as well as high security and increased MTBF.
Abstract
The paper considers the application of the computational analysis of data transmission models in satellite systems for aircraft trajectory control. A system for monitoring the trajectory of ...aircraft using satellite communication systems Iridium and Inmarsat is presented. The scheme of communication between the aircraft board and the control tower takes into account the peculiarities of extreme conditions typical for the Arctic and the Far North. An example of calculating the probability of code combination transformations for an asymmetric channel with independent errors is considered. In this case, the calculations follow the provisions of the theorems of probability theory. Modeled data rates for satellite communication systems Iridium and Inmarsat. It is concluded that the Iridium and Inmarsat systems have a high data transfer rate and a low error rate, and their use as communication systems for transmitting data from an aircraft to an air traffic control center is justified.
The article considers the problem of reducing costs for the development and maintenance of software components. The possibilities of reusing software components and as the result the need for their ...testing are considered. A method of the repeated testing is proposed. It allows achieving the required level of testability of software components that reduces time costs. This method is a more detailed investigation of the neighborhood of the identified failures and the elimination of already verified areas. The software implementation of the repeated testing method in the framework of the Integrated Development Environment developed by the authors is considered. The presented tool allows designers to automate the re-testing procedure partially. It is possible to predict the time of occurrence of the next error based on the data on the detected errors while testing. It is essentially the time between failures. A de-eutrophication model for predicting the mean time between failures and a software tool that implements the given model are proposed. The results obtained by testing on the known data set are presented. The models and approaches described in the article help to solve the problem that is confirmed by the results obtained using the developed software tools.
This article discusses the analysis of the economic effect of increasing the reliability of the information system that provides the processing and storage of information for digital agricultural ...enterprises. A special downtime calculation technique is used, based on the TCO Advisor Client & Server Model. The necessary data for the calculation are presented, as well as intermediate and main indicators. These metrics can also be used to calculate total cost of ownership. It is noted that this information may be of interest to top managers of digital agricultural enterprises who solve problems in assessing the performance of computing servers and networks.
PDF
