Исследование возможности непрямого перелета на ограниченную орбиту вокруг точки либрации L2 системы Земля — Луна
The paper analyzes the possibility of flight into the orbit around the translunar libration point using gravity-assist maneuver near the Moon. The orbits, which spacecraft can enter without the use of intermediate maneuvers after the flyby of the Moon, are studied. The flight from a parking low-Earth orbit into different orbits is simulated. Color maps of characteristics dependent on the parameters of the flyby point and the map showing the areas on the plane corresponding to the quasi-halo orbit, moving on which the spacecraft does not go to the penumbra of the Moon are constructed.
This paper presents a study on the features and characteristics of the Lissajous orbit family around libration point L2 of the Earth-Moon system which allow optimization in terms of improving the communication between an orbiting spacecraft and the Earth.
A procedure has been proposed for calculating limited orbits around the L2 libration points of the Sun–Earth system. The motion of a spacecraft in the vicinity of the libration point has been considered a superposition of three components, i.e., decreasing (stable), increasing (unstable), and limited. The proposed procedure makes it possible to correct the state vector of the spacecraft so as to neutralize the unstable component of the motion. Using this procedure, the calculation of orbits around various types of libration points has been carried out and the dependence on the orbit type on the initial conditions has been studied.
Several missions are planned in Russia to launch spacecraft into the vicinity of the Solar-Terrestrial collinear libration points. The first of them is Spectr-Roentgen-Gamma intended to explore the sky in X-ray and Gamma-ray band. There are technical constraints on this project’s realization, influencing the scenario of inserting the spacecraft into the operational orbit. One of these constraints is the location of the available ground station.
Due to the high latitude of Russian stations it is impossible to have visibility of the spacecraft from them during those phases of flight when the spacecraft is well below the ecliptic plane. To avoid this phenomenon, it is necessary to decrease the orbit amplitude in the direction orthogonal to the ecliptic plane. There are several methods how to do this including one with gravity assist maneuvers near Moon or use of the rocket engine for correction maneuvers, but the simplest – the search of an appropriate option within the family of possible transfer trajectories.
In the paper all these approaches are analyzed and it is shown that for standard scenario for them some difficulties do exist leading to the decrease the reliability of mission at large. The reason is that the thrust of the spacecraft rocket engines is too low, leading to burn durations that are too long.
For more practical approach, it is proposed to use the upper stage of the launcher for the maneuvers intended to decrease the amplitude of the orbit in the ecliptic pole direction. This leads to increasing the duration of spacecraft visibility to an acceptable level for the ground stations situated on the Russian territory. But the most promising and effective option is a single impulse trajectory with an optimal choice of the initial orbital state vector.
Also the problem of reaching the maximum amplitude of the orbit normal to the ecliptic, the “Z-amplitude”, is considered. This goal is to be reached for another project -Millimetron. This project goal is to build a space interferometer with very long base consisting of two telescopes: one in space near the [Sun-Earth L2] libration point and the other on the Earth’s surface.
It is shown that it is possible to put the spacecraft into an orbit with a Z-amplitude value of more than one million kilometers, practically with the same velocity impulse as for orbits with several times less Z-amplitude. The proposed method for this is the appropriate choice of the perigee position of the transfer orbit.
This book constitutes the joint refereed proceedings of the 18th International Conference on Next Generation Wired/Wireless Advanced Networks and Systems, NEW2AN 2018, the 11th Conference on Internet of Things and Smart Spaces, ruSMART 2018. The 64 revised full papers presented were carefully reviewed and selected from 186 submissions. The papers of NEW2AN focus on advanced wireless networking and applications; lower-layer communication enablers; novel and innovative approaches to performance and efficiency analysis of ad-hoc and machine-type systems; employed game-theoretical formulations, Markov chain models, and advanced queuing theory; grapheme and other emerging material, photonics and optics; generation and processing of signals; and business aspects. The ruSMART papers deal with fully-customized applications and services.
The key regulator in the control of aggressive behavior is dopamine receptors. Association of variants in these genes with aggression has been shown in modern populations. However, these studies have not been conducted in traditional cultures. The aim of our study was to investigate population features in distributions of allele and genotype frequencies of DRD2 rs1800497, DRD4 120 bp Ins, and DRD4 exon III polymorphisms and their associations with aggressive behavior in the traditional African populations of Hadza and Datoga, which display a contrast in their culturally permitted aggression. Overall, 820 healthy unrelated Hadza and Datoga individuals were studied. Self‐rated scores of aggression were collected using Buss and Perry's Aggression Questionnaire. Polymerase chain reaction‐Restriction fragment length polymorphism (PCR‐RFLP) was used to determine the genotype of each individual. We show that the Hadza and the Datoga differed significantly in allele and genotype frequencies of all studied loci. Our association analysis detected that only ethnicity and sex of individuals significantly influenced their aggression rank, but we failed to identify any associations of DRD2 rs1800497, DRD4 120 bp Ins, or DRD4 exon III polymorphisms with aggression. Thus, our data have no strong evidence to support the involvement of polymorphisms of DRD2 and DRD4 in controlling aggressive behavior.
This book constitutes the joint refereed proceedings of the 17th International Conference on Next Generation Wired/Wireless Advanced Networks and Systems, NEW2AN 2017, the 10th Conference on Internet of Things and Smart Spaces, ruSMART 2017. The 71 revised full papers presented were carefully reviewed and selected from 202 submissions. The papers of NEW2AN focus on advanced wireless networking and applications; lower-layer communication enablers; novel and innovative approaches to performance and efficiency analysis of ad-hoc and machine-type systems; employed game-theoretical formulations, Markov chain models, and advanced queuing theory; grapheme and other emerging material, photonics and optics; generation and processing of signals; and business aspects. The ruSMART papers deal with fully-customized applications and services. The NsCC Workshop papers capture the current state-of-the-art in the field of molecular and nanoscale communications such as information, communication and network theoretical analysis of molecular and nanonetwork, mobility in molecular and nanonetworks; novel and practical communication protocols; routing schemes and architectures; design/engineering/evaluation of molecular and nonoscale communication systems; potential applications and interconnections to the Internet (e.g. the Internet of Nano Things).
The question of ensuring reliability, especially of durability of mobile communication systems on the stage of planning, is considered in this paper. The purpose of this work is rising quality of projection radio engineering devices (their components) of mobile communication systems. Research of real methods for calculating the indicators of longevity radio engineering devices was conducted for aim achievement. They have some disadvantages, because according to industry standards 4.012.013-84 they use constant value of variation coefficient in mathematical expression. Unified method in the form of IDEF0-diagram was proposed for elimination of defects. It allows to remove quantification of the durability of the constituent parts of the mobile communication systems of «resource» type. Method consists of five successive steps: the formation of source data, updated calculation of variation coefficient, calculation of storage time, evaluation of complex load factor and calculating of indicators of «resource» type. Notably attention is paid to calculating of updated variation coefficient, which makes a significant contribution to the result. It was detected that it is necessary to apply complex load factor in mathematical expressions in the evaluation of resource of radio engineering devices of mobile communicational systems, because it considers both electrical load and temperature, which is explained by the thermally dependent electrical parameters of electrical components. A summary table of the mean group value of the coefficient of variation for certain subgroups of electrical components was compiled. This table is accessory to counting indicators of durability of «resource» type if the necessary electronics are not available in handbooks about reliability. The calculation of the quantitative values of the durability of the video transmitter with the construction of visual dependencies of gamma-percent resource on the complex load factor was completed. Dependences that have been obtained mirror underestimation of gamma-percent resource with the method which is given in industry standards 4.012.013-84 compared with the proposed. It is recommended to integrate the results of research into methodology of calculating of reliability indicators of «resource» type of components at enterprises and research institutes engaged in the development of mobile communication systems.
Since the 1970s, scholars have produced a large body of research attempting to establish the mechanisms by which sexual serial killers come to arrive at a life of repeat fatal violence. From the standpoint of developmental psychology, however, the explanations offered are far too limited in scope. Human development is the product of complex reciprocal transactions that occur between an individual and their environment throughout their life span. This present study is meant to encourage a critical reconsideration of past knowledge (mainly static traits) in favor of the recognition of the complexity of human development. Using life span developmental psychology as a guiding framework, this study traces the developmental mechanisms that come together to shape the psychopathology that drives the motivations of sexual serial killers.
Many electronic devices operate in a cyclic mode. This should be considered when forecastingreliability indicators at the design stage.The accuracy of the prediction and the planning for the event to ensure reliability depends on correctness of valuation and accounting greatest possiblenumber of factors. That in turn will affect the overall progress of the design and, in the end,result in the quality and competitiveness of products
Let G be a semisimple algebraic group whose decomposition into the product of simple components does not contain simple groups of type A, and P⊆G be a parabolic subgroup. Extending the results of Popov , we enumerate all triples (G, P, n) such that (a) there exists an open G-orbit on the multiple flag variety G/P × G/P × . . . × G/P (n factors), (b) the number of G-orbits on the multiple flag variety is finite.
I give the explicit formula for the (set-theoretical) system of Resultants of m+1 homogeneous polynomials in n+1 variables