This paper presents a methodological approach to assessing the technical level of space systems of Earth remote sensing (SSERSs) and geostationary satellite communication systems (GSCSs) developed by the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine together with Yuzhnoye State Design Office. The approach allows one to substantially increase calculation quality and reduce the human factor effect in the determination of this index. This is achieved due to a high level of formalization of the technical level quantification process and the use of mathematical methods employed in the modern decision making theory.The technical level index is a qualitative measure of the perfection of a product and the quality of the products (services) produced with its use. The technical level index is one of the key techno-economic indices of development work. The value of the technical level index is a determining factor (together with the development and operation costs) of the competitiveness of a newly developed space system.The identity of the SSERS and GSCS technical structure, especially that of the platforms of SSERS and GSCS spacecraft, made it possible to construct a unified methodological approach to solving the problem of quantitative assessment of the SSERS and GSCS technical level index. The difference will only be in details of technical level calculation algorithms. The major difference is in the choice of an optimal set of particular technical efficiency indices for each space system.The methodological approach is based on a mathematical model of Saaty's analytic hierarchy process extended by the authors to include mathematical models for accounting as fully as possible for the SSERS and GSCS technical features and checking for errors and contradictions in the judgments of the experts who take part in the preparation of basic data on immeasurable or hard-to-measure SSERS and GSCS techno-economic indices.Based on the presented methodological approach, one may develop a state-of the-art sectorial methodology for SSERS and GSCS technical level quantification.

In most cases, determining the parametric reliability of the mechanical systems (MSs) of a launch vehicle (LV) at the design stage can be reduced to one-and two-dimensional models. The use of the normal distribution in such models is not always justified because the MS parameters often obey distribution laws distinct from the normal one. This paper demonstrates that the LV MS parametric reliability can be estimated using a twodimensional normal copula constructed on the basis of one-dimensional generalized lambda distributions, which show a considerable flexibility. The construction and features of a normal copula of this type are considered; in particular, expressions for the distribution density, regression lines, and the distribution function are presented. Such a distribution allows one to account for the difference of marginal distributions from the normal one and a linear correlation between the components (a linear correlation between the MS parameters is observed in 70 percent of cases). It is shown how the normal copula parameter that characterizes a linear correlation between random variables can be obtained using the method of moments. In this paper, expressions for determining the LV MS parametric reliability are derived using the normal copula constructed on the basis of one-dimensional generalized lambda distributions. With their help, it is shown that accounting for both the difference of marginal distributions of random variables from the normal one (first of all, the skew and the kurtosis) and for a linear correlation between them offers a more accurate prediction of the MS reliability in comparison with the normal case. Accounting for a nonlinear correlation between the MS parameters (a modified FarlieGumbelMorgenstern copula is used for comparison) does not either result in any significant deviation of the reliability index from the values obtained with the use of the normal copula considered. The practical use of the normal copula considered is demonstrated by the example of estimating the probability of the propellant of an LV stage being sufficient for a trouble-free cutoff of the propulsion system.

The research objective is to develop a modern method of an engineering evaluation of Earth remote sensing spacecraft based on an updated hierarchy T. Saati method. Creation of methodic support for a correct engineering evaluation of the state-of-the-art technology is motivated by the importance of this factor for evaluating the competiveness of the rocket and space technology under development. The paper presents a generalized method of the engineering evaluation of rocket and space products and its specification related to the issue of an engineering evaluation of Earth remote sensing spacecraft. The method under consideration has been employed for an engineering evaluation of the Sich-2M satellite in the development of the technical project.

Реферат. В данной статье описаны преимущества (по сравнению с пилотируемыми человеком летательными аппаратами) применения беспилотных летательных аппаратов для научных исследований. Предложено использование самолета на солнечных батареях для многосуточных беспосадочных полетов на большой высоте в Антарктиде. Описаны технические предпосылки, способствовавшие созданию и развитию самолетов на солнечных батареях. Отмечены их особенности и достоинства. На основе разработанной автором математической модели полета самолета выявлены зависимости нагрузки на крыло и скорости от требуемой высоты полета. Показана реализуемость проекта высотного самолета на солнечных батареях с помощью технических средств, которые имеются на сегодняшний день. Даны характеристики самолетов на солнечных батареях, появления которых можно ожидать в ближайшем будущем.

The paper purpose is to demonstrate the opportunities of the Jacobi probability distributions for fitting the statistical populations. The universal Pearson and Johnson systems of the distributions, the generalized lambda distribution and the Gram-Charlier distribution, which are widely used for fitting statistical populations, are analyzed. It is pointed out that the main disadvantage of these distributions is that they do not take into account real limited ranges of variations in the random variables. The paper considers the theoretical problems of the construction of the one-dimensional Jacobi probability distribution, based on the expansion the unknown density function in the term of the system of the orthogonal Jacobi polynomials with variations in a limited interval. The optimality principles of the Jacobi distribution are formulated to approximate the statistical data, and practical recommendations are given for its construction. In particular, the best fitting results are obtained for the Jacobi distribution constructed with the ultraspherical orthogonal Jacobi polynomials. The application of the Jacobi distribution is determined, which is significantly wider than the application of the Gram-Charlier distribution. Methods for determining the limited points of the Jacobi distribution are presented. Examples demonstrate the advantages of the Jacobi distribution for fitting the statistical populations in comparison with the universal distributions used in practice.