Pub Date : 2022-10-28DOI: 10.15407/knit2022.05.015
M. Redka, S. Khoroshylov
The subject of research is the process of creating a neural network model (NNM) for determining the force impact of an ion thruster (IT) plume on an orbital object during non-contact space debris removal. The work aims to develop NNMs and study the influence of various factors on the accuracy of determining the force transmitted by the ion plume of the thruster to a space debris object (SDO). The tasks to resolve are to choose the structures of the NNMs, form a data set and use this data to train and validate the NNMs, and to explore the influence of the model structure and optimizer parameters on the accuracy of force determination. The methods used are plasma physics, computer simulation, deep learning, and optimization using an improved version of stochastic gradient descent. As a result of research, three NNMs have been developed, which differ in the number of hidden layers and neurons in hidden layers. For training and validation of the NNMs, a data set was generated for an SDO approximated by a cylinder using an autosimilar description of the ion plasma propagation. The data set was obtained for various relative positions and orientations of the object in the process of its removal from an orbit. Using this data set, the NNM parameters were optimized with the supervised learning method. The optimizer and its parameters are selected, providing a small error at the stage of validating learning outcomes. It was found that the accuracy of determining the force depends on the relative position and orientation of the SDO, as well as the architecture of the NNM, and the features of this influence were identified. The approach applied allows us to obtain the possibility of using methods of deep learning to determine the force impact of the IT plume on the SDO. The proposed models provide the accuracy of the force impact determination, which is sufficient for solving the considered class of problems. At the same time, NNM makes it possible to obtain results much faster in comparison with the methods used previously. This fact makes the NNMs promising to use both on-board and in mathematical modeling of missions to remove space debris.
{"title":"DETERMINATION OF THE FORCE IMPACT OF AN ION THRUSTER PLUME ON AN ORBITAL OBJECT VIA DEEP LEARNING","authors":"M. Redka, S. Khoroshylov","doi":"10.15407/knit2022.05.015","DOIUrl":"https://doi.org/10.15407/knit2022.05.015","url":null,"abstract":"The subject of research is the process of creating a neural network model (NNM) for determining the force impact of an ion thruster (IT) plume on an orbital object during non-contact space debris removal. The work aims to develop NNMs and study the influence of various factors on the accuracy of determining the force transmitted by the ion plume of the thruster to a space debris object (SDO). The tasks to resolve are to choose the structures of the NNMs, form a data set and use this data to train and validate the NNMs, and to explore the influence of the model structure and optimizer parameters on the accuracy of force determination. The methods used are plasma physics, computer simulation, deep learning, and optimization using an improved version of stochastic gradient descent. As a result of research, three NNMs have been developed, which differ in the number of hidden layers and neurons in hidden layers. For training and validation of the NNMs, a data set was generated for an SDO approximated by a cylinder using an autosimilar description of the ion plasma propagation. The data set was obtained for various relative positions and orientations of the object in the process of its removal from an orbit. Using this data set, the NNM parameters were optimized with the supervised learning method. The optimizer and its parameters are selected, providing a small error at the stage of validating learning outcomes. It was found that the accuracy of determining the force depends on the relative position and orientation of the SDO, as well as the architecture of the NNM, and the features of this influence were identified. The approach applied allows us to obtain the possibility of using methods of deep learning to determine the force impact of the IT plume on the SDO. The proposed models provide the accuracy of the force impact determination, which is sufficient for solving the considered class of problems. At the same time, NNM makes it possible to obtain results much faster in comparison with the methods used previously. This fact makes the NNMs promising to use both on-board and in mathematical modeling of missions to remove space debris.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48103588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-28DOI: 10.15407/knit2022.05.067
The use of elastomers allows us to purposefully change the structure of epoxy compositions, which largely determines the characteristics. Of particular interest are elastomers, such as silicone and polyurethane rubbers. In experimental works for the manufacture of carbon fiber plates, we used the method of manual molding with mechanical pressing. This technology is economical, does not require large labor costs, and less material consumption than when using other methods of formation. The effect of polyurethane and silicone rubbers as modifiers of increasing the impact strength of epoxy resin Etal-Inject-T hot curing has been studied. To determine the compressive strength of carbon fiber, the samples were tested on a universal test machine MUP200. The impact strength of carbon fiber was determined by the Charpy method. It is established that polyurethane and silicone rubbers have the same qualitative effect on the properties of epoxy resins. When modifying carbon fiber with polyurethane rubber with an increase in the content of up to 10%, the impact strength of carbon fiber increases to a maximum of 215 kJ/m2, with a significant increase in compressive strength up to 495 MPa. Optimal results were obtained with polyurethane rubber at 10% content of the substance. The main role of rubber in increasing the strength and elasticity of the material is that when the impact in a small amount of carbon fiber concentrates a lot of mechanical energy, the rubbers are stress concentrators, so the crack arises in the matrix adjacent to the elastomer (rubber). The increase in the toughness of the material can be associated with the formation of a dispersed phase of rubber, which loosens the structure of the cured epoxy resin.
{"title":"Study of the influence of rubber on stremgth properties of carbon plastic","authors":"","doi":"10.15407/knit2022.05.067","DOIUrl":"https://doi.org/10.15407/knit2022.05.067","url":null,"abstract":"The use of elastomers allows us to purposefully change the structure of epoxy compositions, which largely determines the characteristics. Of particular interest are elastomers, such as silicone and polyurethane rubbers. In experimental works for the manufacture of carbon fiber plates, we used the method of manual molding with mechanical pressing. This technology is economical, does not require large labor costs, and less material consumption than when using other methods of formation. The effect of polyurethane and silicone rubbers as modifiers of increasing the impact strength of epoxy resin Etal-Inject-T hot curing has been studied. To determine the compressive strength of carbon fiber, the samples were tested on a universal test machine MUP200. The impact strength of carbon fiber was determined by the Charpy method. It is established that polyurethane and silicone rubbers have the same qualitative effect on the properties of epoxy resins. When modifying carbon fiber with polyurethane rubber with an increase in the content of up to 10%, the impact strength of carbon fiber increases to a maximum of 215 kJ/m2, with a significant increase in compressive strength up to 495 MPa. Optimal results were obtained with polyurethane rubber at 10% content of the substance. The main role of rubber in increasing the strength and elasticity of the material is that when the impact in a small amount of carbon fiber concentrates a lot of mechanical energy, the rubbers are stress concentrators, so the crack arises in the matrix adjacent to the elastomer (rubber). The increase in the toughness of the material can be associated with the formation of a dispersed phase of rubber, which loosens the structure of the cured epoxy resin.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67116999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-25DOI: 10.15407/knit2022.05.027
V. Khramtsov, I. Vavilova, D. Dobrycheva, M. Vasylenko, O. V. Melnyk, A. Elyiv, V. Akhmetov, A. Dmytrenko
This paper follows a series of our works on the applicability of various machine learning methods to morphological galaxy classification (Vavilova et al., 2021, 2022). We exploited the sample of ~315800 low-redshift SDSS DR9 galaxies with absolute stellar magnitudes of −24m < Mr < −19.4m at 0.003 < z < 0.1 redshifts as a target data set for the CNN classifier. Because it is tightly overlapped with the Galaxy Zoo 2 (GZ2) sample, we use these annotated data as the training data set to classify galaxies into 34 detailed features. In the presence of a pronounced difference in visual parameters between galaxies from the GZ2 training data set and galaxies without known morphological parameters, we applied novel procedures, which allowed us for the first time to get rid of this difference for smaller and fainter SDSS galaxies with mr < 17.7. We describe in detail the adversarial validation technique as well as how we managed the optimal train-test split of galaxies from the training data set to verify our CNN model based on the DenseNet-201 realistically. We have also found optimal galaxy image transformations, which help increase the classifier’s generalization ability. We demonstrate for the first time that implication of the CNN model with a train-test split of data sets and size-changing function simulating a decrease in magnitude and size (data augmentation) significantly improves the classification of smaller and fainter SDSS galaxies. It can be considered as another way to improve the human bias for those galaxy images that had a poor vote classification in the GZ project. Such an approach, like autoimmunization, when the CNN classifier, trained on very good galaxy images, is able to retrain bad images from the same homogeneous sample, can be considered co-planar to other methods of combating such a human bias. The most promising result is related to the CNN prediction probability in the classification of detailed features. The accuracy of the CNN classifier is in the range of 83.3—99.4 % depending on 32 features (exception is for “disturbed” (68.55 %) and “arms winding medium” (77.39 %) features). As a result, for the first time, we assigned the detailed morphological classification for more than 140000 low-redshift galaxies, especially at the fainter end. A visual inspection of the samples of galaxies with certain morphological features allowed us to reveal typical problem points of galaxy image classification by shape and features from the astronomical point of view. The morphological catalogs of low-redshift SDSS galaxies with the most interesting features are available through the UkrVO website (http://ukr-vo.org/galaxies/) and VizieR.
本文介绍了我们关于各种机器学习方法在形态星系分类中的适用性的一系列工作（Vavilova et al.，2022022）。我们利用了约315800个低红移SDSS DR9星系的样本作为CNN分类器的目标数据集，这些星系的绝对恒星星等为−24m
{"title":"Machine learning technique for morphological classification of galaxies from the SDSS. III. The CNN image-based inference of detailed features","authors":"V. Khramtsov, I. Vavilova, D. Dobrycheva, M. Vasylenko, O. V. Melnyk, A. Elyiv, V. Akhmetov, A. Dmytrenko","doi":"10.15407/knit2022.05.027","DOIUrl":"https://doi.org/10.15407/knit2022.05.027","url":null,"abstract":"This paper follows a series of our works on the applicability of various machine learning methods to morphological galaxy classification (Vavilova et al., 2021, 2022). We exploited the sample of ~315800 low-redshift SDSS DR9 galaxies with absolute stellar magnitudes of −24m < Mr < −19.4m at 0.003 < z < 0.1 redshifts as a target data set for the CNN classifier. Because it is tightly overlapped with the Galaxy Zoo 2 (GZ2) sample, we use these annotated data as the training data set to classify galaxies into 34 detailed features. In the presence of a pronounced difference in visual parameters between galaxies from the GZ2 training data set and galaxies without known morphological parameters, we applied novel procedures, which allowed us for the first time to get rid of this difference for smaller and fainter SDSS galaxies with mr < 17.7. We describe in detail the adversarial validation technique as well as how we managed the optimal train-test split of galaxies from the training data set to verify our CNN model based on the DenseNet-201 realistically. We have also found optimal galaxy image transformations, which help increase the classifier’s generalization ability. We demonstrate for the first time that implication of the CNN model with a train-test split of data sets and size-changing function simulating a decrease in magnitude and size (data augmentation) significantly improves the classification of smaller and fainter SDSS galaxies. It can be considered as another way to improve the human bias for those galaxy images that had a poor vote classification in the GZ project. Such an approach, like autoimmunization, when the CNN classifier, trained on very good galaxy images, is able to retrain bad images from the same homogeneous sample, can be considered co-planar to other methods of combating such a human bias. The most promising result is related to the CNN prediction probability in the classification of detailed features. The accuracy of the CNN classifier is in the range of 83.3—99.4 % depending on 32 features (exception is for “disturbed” (68.55 %) and “arms winding medium” (77.39 %) features). As a result, for the first time, we assigned the detailed morphological classification for more than 140000 low-redshift galaxies, especially at the fainter end. A visual inspection of the samples of galaxies with certain morphological features allowed us to reveal typical problem points of galaxy image classification by shape and features from the astronomical point of view. The morphological catalogs of low-redshift SDSS galaxies with the most interesting features are available through the UkrVO website (http://ukr-vo.org/galaxies/) and VizieR.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49300949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.071
M. Fys, P. Zazuliak, A. Sohor
A method for determining the gravitational potential of a celestial body whose surface is a sphere or ellipsoid with an abrupt mass distribution function is proposed. For these cases, the formulas for determining the internal potential and gravity are obtained. The calculations performed according to these formulas make it possible to analyze the contribution of the ellipticity of the planet to the value of its internal potential and compare it with the magnitude of the centrifugal force for the planets of the Earth group (Earth, Mars, Venus) and the Moon.
{"title":"Gravity potential and its component of centrifugal force inside the ellipsoidal planet","authors":"M. Fys, P. Zazuliak, A. Sohor","doi":"10.15407/knit2022.04.071","DOIUrl":"https://doi.org/10.15407/knit2022.04.071","url":null,"abstract":"A method for determining the gravitational potential of a celestial body whose surface is a sphere or ellipsoid with an abrupt mass distribution function is proposed. For these cases, the formulas for determining the internal potential and gravity are obtained. The calculations performed according to these formulas make it possible to analyze the contribution of the ellipticity of the planet to the value of its internal potential and compare it with the magnitude of the centrifugal force for the planets of the Earth group (Earth, Mars, Venus) and the Moon.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67117441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.003
I. A. Bespalko, L. D. Hrekov, D. V. Pekariev, D. Fedorchuk
The concept of an information system to provide the monitoring of space in order to increase military security is proposed with the accounted-for peculiarities of solving problems by the domestic structures of the security and defense sector. The concept is based on the separation of the functionality of open and specialized parts of the algorithm and software support for analyzing the space situation with the attainment of their compatibility. The results of the capability analysis of the publicly available software, which can be used for the evaluation of the space situation as an additional means, are presented. The functional model of the information system to provide the monitoring of space was developed, and a decomposition of its main functional block — a general assessment of the space situation has been carried out. The main software components of the algorithm and software support for the overall estimating of the space situation are determined: detection and monitoring of space objects, maintenance of the database of space objects, modeling and display of the space situation, and their main tasks are outlined. The structural scheme of the software and hardware complex of the general estimation of space situation is developed. Further ways of research are offered: concretization of the functionality of the components of the algorithms and software support of the general estimation of the space situation, substantiation and development of databases’ structures of space objects and objects of space activity, creation of the relevant software and hardware complexes and check of the adequacy of the used mathematical models, as well as issues of information security.
{"title":"The concept of information system for providing monitoring of space in order to increase military security","authors":"I. A. Bespalko, L. D. Hrekov, D. V. Pekariev, D. Fedorchuk","doi":"10.15407/knit2022.04.003","DOIUrl":"https://doi.org/10.15407/knit2022.04.003","url":null,"abstract":"The concept of an information system to provide the monitoring of space in order to increase military security is proposed with the accounted-for peculiarities of solving problems by the domestic structures of the security and defense sector. The concept is based on the separation of the functionality of open and specialized parts of the algorithm and software support for analyzing the space situation with the attainment of their compatibility. The results of the capability analysis of the publicly available software, which can be used for the evaluation of the space situation as an additional means, are presented. The functional model of the information system to provide the monitoring of space was developed, and a decomposition of its main functional block — a general assessment of the space situation has been carried out. The main software components of the algorithm and software support for the overall estimating of the space situation are determined: detection and monitoring of space objects, maintenance of the database of space objects, modeling and display of the space situation, and their main tasks are outlined. The structural scheme of the software and hardware complex of the general estimation of space situation is developed. Further ways of research are offered: concretization of the functionality of the components of the algorithms and software support of the general estimation of the space situation, substantiation and development of databases’ structures of space objects and objects of space activity, creation of the relevant software and hardware complexes and check of the adequacy of the used mathematical models, as well as issues of information security.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67117296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.031
V. Gristchak, D. V. Hryshchak, N. Dyachenko, V. V. Baburov
The buckling problem of an elastic compound shell structure with a variable Gaussian curvature of the middle surface, especially the middle surface meridian curvature sign, under the action of external pressure and axial loading is considered. In continuation of the previous research of the authors, this paper is devoted, in particular, to examining the influence of the negative Gaussian curvature sign of one of its compartments on stability. The solution is based on using the method of finite differences for basic stability equations of each compartment in the case when one of them can have a negative curvature of the meridian, taking into account the discreteness of the intermediate rib location and their rigidity from the initial curvature plane as well. The obtained solution allows visualizing the buckling modes under various combinations of external loading and identifying rational, according to overall buckling modes, geometric and rigidity parameters of the system being investigated.
{"title":"The influence of the Gaussian curvature sign of the compound shell structure’s middle surface on local and overall buckling under combined loading","authors":"V. Gristchak, D. V. Hryshchak, N. Dyachenko, V. V. Baburov","doi":"10.15407/knit2022.04.031","DOIUrl":"https://doi.org/10.15407/knit2022.04.031","url":null,"abstract":"The buckling problem of an elastic compound shell structure with a variable Gaussian curvature of the middle surface, especially the middle surface meridian curvature sign, under the action of external pressure and axial loading is considered. In continuation of the previous research of the authors, this paper is devoted, in particular, to examining the influence of the negative Gaussian curvature sign of one of its compartments on stability. The solution is based on using the method of finite differences for basic stability equations of each compartment in the case when one of them can have a negative curvature of the meridian, taking into account the discreteness of the intermediate rib location and their rigidity from the initial curvature plane as well. The obtained solution allows visualizing the buckling modes under various combinations of external loading and identifying rational, according to overall buckling modes, geometric and rigidity parameters of the system being investigated.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47778951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.078
Y. Yatskiv
The article displays the material of 1991 from the author’s archive, which is devoted to the problems of space research arrangement and the space industry authority in independent Ukraine. A brief description of the space research level in Ukraine at that time is given. The active participation of Ukraine in the activity of international organizations and the implementation of USSR space programs are highlighted. The significant achievements and acquirements of scientific and design teams in the space research branch are emphasized. Among them, there were the rocket design center DB “Pivdenne” (now — Yangel Yuzhnoye State Design Office), E. O. Paton Electric Welding Institute of NAS of Ukraine, and many other enterprises and scientific institutions in Ukraine. In new conditions, under the newly acquired independence, the formidable task of preserving the aerospace industry of Ukraine arose. Within this task, it was necessary to preserve scientific and developing potential and to provide perspectives for scientific and technical progress. All this was possible only within the framework of the concept that had to be developed and which would contain the main goals of the national politics of Ukraine as an independent state in the branch of exploration and exploitation of space. It was necessary to create the aerospace agency of Ukraine for the coordination of space programs and to develop a law to regulate its activities. One more task was to adopt the state program of space exploration by the Verkhovna Rada, the program, which had to provide for the progress of fundamental and applied space research.
{"title":"From the history of space research in Ukraine. 1. The performance of space research as of 1991 year","authors":"Y. Yatskiv","doi":"10.15407/knit2022.04.078","DOIUrl":"https://doi.org/10.15407/knit2022.04.078","url":null,"abstract":"The article displays the material of 1991 from the author’s archive, which is devoted to the problems of space research arrangement and the space industry authority in independent Ukraine. A brief description of the space research level in Ukraine at that time is given. The active participation of Ukraine in the activity of international organizations and the implementation of USSR space programs are highlighted. The significant achievements and acquirements of scientific and design teams in the space research branch are emphasized. Among them, there were the rocket design center DB “Pivdenne” (now — Yangel Yuzhnoye State Design Office), E. O. Paton Electric Welding Institute of NAS of Ukraine, and many other enterprises and scientific institutions in Ukraine. In new conditions, under the newly acquired independence, the formidable task of preserving the aerospace industry of Ukraine arose. Within this task, it was necessary to preserve scientific and developing potential and to provide perspectives for scientific and technical progress. All this was possible only within the framework of the concept that had to be developed and which would contain the main goals of the national politics of Ukraine as an independent state in the branch of exploration and exploitation of space. It was necessary to create the aerospace agency of Ukraine for the coordination of space programs and to develop a law to regulate its activities. One more task was to adopt the state program of space exploration by the Verkhovna Rada, the program, which had to provide for the progress of fundamental and applied space research.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48577502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.018
A. Pirozhenko, A. Maslova, V. Vasyliev
The article deals with the movement of satellites in low near-circular orbits of the Earth. An analytical model is constructed, which consists of formulas describing the change of the osculating elements and averaged equations. An algorithm for constructing a second approximation of the influence of zonal harmonics of the geopotential on the movement of satellites in almost circular orbits is presented. For the second and third zonal harmonics, formulas are given for the osculating and average elements describing the motion of the satellite in the second approximation in small parameters. The introduction of special variables for almost circular orbits made it possible to significantly simplify the procedure for constructing the second approximation of the influence of zonal harmonics. The article provides a justification for the accuracy of the analytical model for the considered orbits. The constructed model of changes in the average elements of the orbit describes the basic principles of motion. With a sufficiently high accuracy, this model describes the changes in the average elements of the orbit with simple analytical formulas and is convenient for analyzing the properties of orbits and pre-selecting a reference orbit for a specific mission.
{"title":"Analytical model of satellite motion in almost circular orbits under the influence of zonal harmonics of geopotential","authors":"A. Pirozhenko, A. Maslova, V. Vasyliev","doi":"10.15407/knit2022.04.018","DOIUrl":"https://doi.org/10.15407/knit2022.04.018","url":null,"abstract":"The article deals with the movement of satellites in low near-circular orbits of the Earth. An analytical model is constructed, which consists of formulas describing the change of the osculating elements and averaged equations. An algorithm for constructing a second approximation of the influence of zonal harmonics of the geopotential on the movement of satellites in almost circular orbits is presented. For the second and third zonal harmonics, formulas are given for the osculating and average elements describing the motion of the satellite in the second approximation in small parameters. The introduction of special variables for almost circular orbits made it possible to significantly simplify the procedure for constructing the second approximation of the influence of zonal harmonics. The article provides a justification for the accuracy of the analytical model for the considered orbits. The constructed model of changes in the average elements of the orbit describes the basic principles of motion. With a sufficiently high accuracy, this model describes the changes in the average elements of the orbit with simple analytical formulas and is convenient for analyzing the properties of orbits and pre-selecting a reference orbit for a specific mission.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47168507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.15407/knit2022.04.039
A. Golubaev, Y. Gorbanev, O. Shulga, О. А. Andreev, F. Bushuev, A. Vidmachenko, B. Hrudynin, B. Zhilyaev, M. Kaliuzhnyi, P. Kozak, M. O. Kulichenko, Y. Malynovskyi, А. М. Mozgova, S. Savchuk, A. Steklov, Y. Sumaruk, L. Yankiv-Vitkovska
The development of meteor astronomy in modern Ukraine is considered. The specificity of meteor observation methods requires, first of all, the organization of a network of corresponding observation points. To achieve this goal, it is proposed to combine the scientific and technical capabilities of participating organizations in the form of the Ukrainian Meteor Observation Network (UMON). UMON is a set of two or more permanent observation stations located on the territory of Ukraine, which have the hardware and software for basic and one-sided observations of meteors in different wavelength ranges and conduct such observations. UMON aims to solve important problems of meteor research, structure and evolution of meteor streams and showers, the interaction of meteoroids with the Earth’s atmosphere and their chemical composition. The scientific and technical products of UMON stations are the results of high-precision basic or one-sided observations of meteors in different wavelength ranges, as well as of fundamental and applied scientific and technical research.
{"title":"Creation of the Ukrainian meteor observation network: instruments, methods for processing, observatin possibilities","authors":"A. Golubaev, Y. Gorbanev, O. Shulga, О. А. Andreev, F. Bushuev, A. Vidmachenko, B. Hrudynin, B. Zhilyaev, M. Kaliuzhnyi, P. Kozak, M. O. Kulichenko, Y. Malynovskyi, А. М. Mozgova, S. Savchuk, A. Steklov, Y. Sumaruk, L. Yankiv-Vitkovska","doi":"10.15407/knit2022.04.039","DOIUrl":"https://doi.org/10.15407/knit2022.04.039","url":null,"abstract":"The development of meteor astronomy in modern Ukraine is considered. The specificity of meteor observation methods requires, first of all, the organization of a network of corresponding observation points. To achieve this goal, it is proposed to combine the scientific and technical capabilities of participating organizations in the form of the Ukrainian Meteor Observation Network (UMON). UMON is a set of two or more permanent observation stations located on the territory of Ukraine, which have the hardware and software for basic and one-sided observations of meteors in different wavelength ranges and conduct such observations. UMON aims to solve important problems of meteor research, structure and evolution of meteor streams and showers, the interaction of meteoroids with the Earth’s atmosphere and their chemical composition. The scientific and technical products of UMON stations are the results of high-precision basic or one-sided observations of meteors in different wavelength ranges, as well as of fundamental and applied scientific and technical research.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67117390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-18DOI: 10.15407/knit2022.03.003
K. Yushchenko, O. Yarovytsyn, G. D. Khrushchov, I. Petrik, S. L. Chygileichyk
In current work, peculiarities of the micro-plasma powder welding deposition process applied to the batch refurbishment of D-18T aircraft engine HPT blades made of ZhS32-VI nickel superalloy with limited weldability have been studied. It has been demonstrated that extending operating resource over 6-8 thousand hours leads to an increase in ZhS32-VI “base-deposited metal” weld’s cracking susceptibility during welding and subsequent thermal processing operations. It has been shown that providing stable forming of deposited bead on the shroud edge’s surface requires applying nonstationary impulse modes of straight polarity welding current. Considering the significant amount of technological parameters of the process studied, subjective analysis of such welding modes is extremely complicated. We have introduced the method of specifying requirements for such single-layer micro-plasma powder welding deposition modes with welding current in a range of 7-20 A according to the criteria of effective arc heating power and heat input, which involves using the system for registration and digital processing of welding current-welding bead deposition time dependency. Based on the analysis of statistical data on the quantitative evaluation of cracking susceptibility of the investigated weld, the optimal range of average values has been discovered for these generalized welding deposition mode parameters to be applied in a manual or automated process, which provides no more than several percent of cracked blades detected at the end of refurbishment technological cycle. We have shown that significant technological parameters, which affect the amount of technological defects during mentioned blades’ refurbishment, are the average value of effective welding current and ZhS32 superalloy powder quality, primarily determined by oxygen and nitrogen average weight content in its dispersed particles. It was also shown that the increase in average weight content of gas impurities in the filler powder, primarily oxygen, causes a significant increase in energy consumed on deposited bead formation during the micro-plasma powder deposition process. An initial quality control method for the ZhS32-VI filler powder range has been proposed. The method is based on the average weight content of oxygen and nitrogen, evaluated by reducing fusion in transporting gas flow and on evaluation criteria of effective arc heating power and heat input average values of witness sample blades’ refurbishment process and their conformity to previously defined optimal. An evaluation of future application possibilities for registration systems and deposition mode analysis in batch repair conditions of nickel superalloy aircraft parts has been introduced.
{"title":"RESEARCH AND OPTIMIZATION OF REFURBISHMENT OF HPT BLADES OF THE D-18T AIRCRAFT GAS TURBINE ENGINE BY MICRO-PLASMA POWDER WELDING","authors":"K. Yushchenko, O. Yarovytsyn, G. D. Khrushchov, I. Petrik, S. L. Chygileichyk","doi":"10.15407/knit2022.03.003","DOIUrl":"https://doi.org/10.15407/knit2022.03.003","url":null,"abstract":"In current work, peculiarities of the micro-plasma powder welding deposition process applied to the batch refurbishment of D-18T aircraft engine HPT blades made of ZhS32-VI nickel superalloy with limited weldability have been studied. It has been demonstrated that extending operating resource over 6-8 thousand hours leads to an increase in ZhS32-VI “base-deposited metal” weld’s cracking susceptibility during welding and subsequent thermal processing operations. It has been shown that providing stable forming of deposited bead on the shroud edge’s surface requires applying nonstationary impulse modes of straight polarity welding current. Considering the significant amount of technological parameters of the process studied, subjective analysis of such welding modes is extremely complicated. We have introduced the method of specifying requirements for such single-layer micro-plasma powder welding deposition modes with welding current in a range of 7-20 A according to the criteria of effective arc heating power and heat input, which involves using the system for registration and digital processing of welding current-welding bead deposition time dependency. Based on the analysis of statistical data on the quantitative evaluation of cracking susceptibility of the investigated weld, the optimal range of average values has been discovered for these generalized welding deposition mode parameters to be applied in a manual or automated process, which provides no more than several percent of cracked blades detected at the end of refurbishment technological cycle. We have shown that significant technological parameters, which affect the amount of technological defects during mentioned blades’ refurbishment, are the average value of effective welding current and ZhS32 superalloy powder quality, primarily determined by oxygen and nitrogen average weight content in its dispersed particles. It was also shown that the increase in average weight content of gas impurities in the filler powder, primarily oxygen, causes a significant increase in energy consumed on deposited bead formation during the micro-plasma powder deposition process. An initial quality control method for the ZhS32-VI filler powder range has been proposed. The method is based on the average weight content of oxygen and nitrogen, evaluated by reducing fusion in transporting gas flow and on evaluation criteria of effective arc heating power and heat input average values of witness sample blades’ refurbishment process and their conformity to previously defined optimal. An evaluation of future application possibilities for registration systems and deposition mode analysis in batch repair conditions of nickel superalloy aircraft parts has been introduced.","PeriodicalId":42936,"journal":{"name":"Space Science and Technology-Kosmicna Nauka i Tehnologia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67117229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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