Calculation and Study of Limited Orbits around the L2 Libration Point of the Sun–Earth System
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.
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.
Simulating principles of proposed attribute (A) and object-attribute (OA) architectures of computer systems (CS) that implement the dataflow execution model, and the results of a dataflow-supercomputer system simulation are described. A new formalism of "Attribute Nets" (A-nets) is proposed for mathematical modeling of dataflow-CS that differs significantly from apparatus of Petri Nets. This formalism lays foundation for the OA-programming&simulation environment of a dataflow-CS which is used in development programming and test of the OA-supercomputer system.
The following topics were dealt with: human/computer interfaces; texture, depth and motor perception; neural nets; fuzzy systems; learning; product/process design; simulation; robotics; visual system cybernetics; batch processes; image compression and interpretation; AI applications; fuzzy adaptive control; decision modelling; agile manufacturing; service sector; inductive algorithms; complex systems; Petri nets; real time imaging; KBS; machine recognition; requirements engineering; inspection and shop floor control; environmental decision making; medicine; supervisory control; discrete event systems; power systems; software methods; heuristic search; vision systems; database systems; information modelling; facility design and material handling; conflict resolution; emergency management; genetic algorithms; decision making and path planning; IVHS; senses approximation; intelligent user interface; robust controllers for mechanical systems; cognitive and learning systems; command and control systems; pilot associate systems; neural net applications; real time systems; mobile robot visual processes; medical applications; utility energy systems; machine recognition; computing systems design; software engineering; military applications; data analysis; stochastic processes; guided vehicles; and stability and compensation.
The results concern roll pass design for rolling a round bar of a 20mm diameter from a 55mm diameter input. Concerning materials, this roll pass design must cover a wide range of steels, from low-carbon micro-alloyed steels to stainless steels. The roll pass design proposal takes into consideration lower plasticity of certain steels. The comparison was enabled by suggesting two roll pass designs. The classical oval-round roll pass design, where the maximum extension coefficient is set to 1.55 in oval and 1.22 in round grooves. The second roll pass design uses a combination of smooth part of the roll (curves) and round roll passes. Distribution of the extension coefficient in individual passes is similar to that of oval-round series. The paper also compares values of energy-force parameters calculated analytically using the method of finite elements. If we compare the distribution of temperature, stress and size of the grain, it is proved that the oval-round roll pass designs are the best as far as the balanced distribution of the above-mentioned values is concerned. The roll pas design combining smooth part of the roll with a round part does not achieve such balance. However, its advantage lies in far lower requirement for the needed length of the working part of the roll. Five passes are carried out on the smooth part of the roll, which considerably cuts down the required length of the roll body. Therefore it is this variant that will be used in the laboratory of wire rolling created within the project RMSTC.
Mathematical and computer simulation of economic processes.
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.
In the article are esteemed assigning and main capabilities of the subsystem of the analysis and maintenance of thermal values of designs of radio electronic means ASONIKA-T, and also principles of simulation of thermal processes in designs with the help of the subsystem ASONIKA-T. The example of simulation of thermal processes in a standard design is adduced.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.