Sharp Boundaries of Solar Wind Plasma Structures and an Analysis of Their Pressure Balance

This work is devoted to studying the sharp boundaries of small-scale structures of the solar wind according to the data of measurements with high time resolution onboard the INTERBALL-1 satellite and simultaneous measurements of the WIND spacecraft. Such issues as the character of change of various plasma and magnetic field parameters on these boundaries, the duration of boundary passage and the balance of the total (thermal plus magnetic) pressure on the boundaries of the structures are considered. On the basis of the vast statistical material available, the typical conditions in the solar wind are investigated, in which such sharp boundaries are observed.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 163–170.Original Russian Text Copyright © 2005 by Riazantseva, Khabarova, Zastenker, Richardson.     

Variations of Protons and Doubly Ionized Helium Ions in the Solar Wind

Cosmic Research - We investigated variations on scales of 104–105 km and local spatial inhomogeneities in the density of protons Np, doubly ionized helium ions (α-particles) Nα, and...     

用太阳舵控制大型挠性体太空帆的控制方法

本文论述了一种用太阳舵控制大型挠性体太空帆的控制方法。介绍了太阳舵控制原理、控制方案,给出了控制规律,推导了解耦控制力矩方程。最后分析了挠性振动的稳定性控制。     

Properties of Sharp and Large Changes in the Solar Wind Ion Flux (Density)

The results of a detailed study of large (by 20% and more) and sharp (faster than ten minutes) changes of the ion flux in the solar wind are presented. The data are provided by regular measurements onboard the INTERBALL-1 satellite in the period 1996–1999. Using statistical analysis, we obtained the distribution of these changes in their absolute and relative strength. It is shown that, for a considerable proportion of the events, such sharp and large changes of the ion flux (density) take place under conditions of fairly constant values of the solar wind velocity and of both the magnitude and components of the interplanetary magnetic field.     

利用等离子体通道实现空间太阳能无线能量传输

空间太阳能电站是高效利用太阳能的有效途径,受到了国际的广泛关注。空间无线能量传输技术是空间太阳能电站的关键技术之一。文章首先分析了微波与激光无线能量传输技术的问题,根据空间太阳能传输的具体需求进一步提出基于等离子体通道的无线能量传输技术,并对基于此项技术的空间太阳能传输系统进行了论证,完善并发展了空间太阳能传输模型。基于等离子体通道的无线能量传输技术为多个领域的能量补给提供了新颖的技术途径,是具有广阔应用前景的战略选择。     

Quasi-synchronous orbits and their employment for the approach of a spacecraft to Phobos

The problem of construction of quasi-synchronous orbits which pass through a prescribed point over the surface of Phobos at a prescribed instant of time is considered. The orbits should pass as close as possible to the surface of Phobos at each passage above the planned region of landing.     

Transport Characteristics of Macroparticles in Dusty Plasma Induced by Solar Radiation under Microgravity Conditions

The transport characteristics of macroparticles, charged by the solar radiation under microgravity conditions, were investigated by analyzing the videorecords of experiments carried out onboard the Mirorbital station. The temperature, distributions of velocities, charge, friction coefficient, and diffusion coefficient were obtained for bronze particles.     

Evolution of the Orbit of an Earth Satellite with a Solar Sail

The efficiency of using the light pressure of solar radiation for increasing the semimajor axis of the orbit of an Earth Satellite carrying a solar sail is estimated. The orbit is nearly circular and has an altitude of about 900 km. The satellite is in the mode of single-axis solar orientation: it rotates at an angular velocity of 1 deg/s around the axis of symmetry, which traces the direction to the Sun. This mode is maintained by the solar sail, which serves in this case as a solar stabilizer. The following method of increasing the semimajor axis of the orbit (which is equivalent to increasing the total energy of the satellite's orbital motion) is considered. On those sections of the orbit, where the angle between the light pressure force acting upon the sail and the vector of geocentric velocity of the satellite does not exceed a specified limit, the sail is functioning as a solar stabilizer. On those sections of the orbit, where the above-indicated angle exceeds this limit, the sail is furled by way of turning the edges of the petals towards the Sun. Such a control increases the semimajor axis by more than 150 km for three months of flight. In this case, the accuracy of solar orientation decreases insignificantly.     

ADN与硝胺氧化剂的相互作用

用高压差示扫描量热法(PDSC)和热重-微商热重法(TG-DTG),研究了高能氧化剂ADN(二硝酰胺铵)的热分解及其与HMX和RDX的相互作用。结果表明,ADN与HMX和RDX之间存在着强烈的相互作用。因部分HMX溶于熔融的ADN中,而参与了ADN组分的分解,ADN的放热分解峰温因压力升高而提高,而HMX产生了双分解峰。大量的RDX因ADN的熔融而提前液化与ADN一起分解,因ADN气相产物的抑制作用,使混合体系中RDX组分常压下的分解峰温后移,而RDX自身分解气相产物的催化作用,使其高压下的分解峰温前移。     

Solar Probe Mission with Multiple Gravity-Assist Maneuvers Realized with Conversion Launchers

The trajectories of solar missions that could be realized with conversion launchers are investigated. The insufficient energy resources of the rocket launchers is compensated by multiple gravity-assist maneuvers near terrestrial planets. A method based on the construction of a set of attainability for all the mission trajectories rather than on optimization of separate trajectories is presented, which makes it possible to analyze the problem more widely and to find global extremums using various criteria. Detailed features of the most rational trajectories are given.     

Trajectories for missions of low-thrust spacecraft aimed at delivery of soil samples from main belt asteroids and Phobos

Trajectories of spacecraft with electro-jet low-thrust engines are studied for missions planning to deliver samples of matter from small bodies of the Solar System: asteroids Vesta and Fortuna, and Martian moon Phobos. Flight trajectories are analyzed for the mission to Phobos, the limits of optimization of payload spacecraft mass delivered to it are determined, and an estimate is given to losses in the payload mass when a low-thrust engine with constant outflow velocity is used. The model of an engine with ideally regulated low thrust is demonstrated to be convenient for calculations and analysis of flight trajectories of a low-thrust spacecraft.     

利用太阳帆定点探测器在地一月系共线平动点附近的探讨

共线平动点附近的运动仅仅是条件稳定的,探测器的轨道需要经过控制才能维持在其附近.以地-月系11点和12点附近大振幅晕轨道的控制为例,探讨了太阳帆在定点这类探测器中的应用.首先,考虑了月球轨道的偏心率和太阳辐射的影响,给出了太阳帆对日定向的探测器轨道的低阶分析解,并在此基础上构造了在太阳系真实引力模型下一段时间内维持在共线平动点附近的拟周期轨道.然后,给出了两种利用太阳帆的控制方案,一是固定面质比而改变太阳帆法线的方向,另一是固定太阳帆对日定向而改变面质比,并对两种方案分别作了数值模拟.最后,文章探讨了测控误差及地、月影对轨道控制的影响.     

太阳帆技术综述

文章简要阐述了太阳帆的概念、主要结构和技术,参考美国L’Garde公司的太阳帆展开设计,对涉及的充气及刚化予以概述,为研究分析太阳帆的展开技术提供借鉴。     

Single-Axis Solar Orientation of a Satellite of the Earth

The possibility of using the mode of single-axis solar orientation is considered for a satellite placed into a nearly circular orbit with an altitude of 900 km and bearing a solar sail. The satellite (together with the sail) has an axisymmetric structure, its symmetry axis being the principal central axis of the maximum moment of inertia. The center of the sail pressure lies on this axis and is displaced with respect to the satellite's center of mass. The symmetry axis of the satellite is set to the Sun so that its center of mass would be located between the Sun and the pressure center and would rotate around this axis with an angular velocity of a few degrees per second. The satellite's axis of symmetry makes a slow precession under the action of the gravitational moment and the moment of light pressure forces. Though the maximum magnitudes of these moments are comparable, the moment of the light pressure forces dominates and controls the precession in such a way that the symmetry axis orientation to the Sun remains unchanged.     

Optimization of the Flight of a Spacecraft with a Solar Sail from the Earth to Mars with a Perturbation Maneuver near Venus

The trajectories of the fastest flight of a spacecraft (SC) with a solar sail from the Earth's sphere of activity to the Martian sphere of activity including the section of a perturbation maneuver near Venus are investigated. The planetary spheres of activity are assumed to be point-like; i.e., the maneuver section and the initial and final positions of the SC coincide with the corresponding positions of the planets. The initial velocity of the SC is assumed to be equal to the Earth's velocity, so that no leveling of the velocities of the SC and Mars in the final point of the flight is required. The perturbation maneuver is considered as a jump of the heliocentric velocity of the SC at the point of its contact with Venus, which does not change the magnitude of its Venus-centric velocity. The orbits of planets are assumed to be circular and coplanar; the SC trajectory lies at the plane of these orbits. The sail is planar with a specularly reflecting surface. The trajectories of optimum flights are determined as a result of solving the boundary value problem of the Pontryagin maximum principle. The families of solutions to this problem depending on the initial angular positions of Venus and Mars are constructed by the method of continuation over a parameter.