Venus transfer design by combining invariant manifolds and low-thrust arcs

The design of interplanetary trajectories based on patched circular restricted three body models is gradually becoming a valuable alternative to the classical patched conic approach. The main advantage offered by such a model is the possibility to exploit the manifold dynamics to move naturally far from or toward a body. Generally, propulsive maneuvers are required to match these structures. Low-thrust arcs offer the possibility to have a significant propellant mass reduction when moving from manifold to manifold. The aim of this paper is to present a methodology to design low-thrust trajectories between two planetary orbits connecting the manifolds of two circular three body systems. The approach is based on a grid search on the main parameters governing the solution to identify those trajectories moving within the manifold images on given Poincarè sections. The value of the Jacoby constant of the target libration point periodic orbit is chosen as stop condition for the thrusting phases. Ballistic arcs follow up to the proper Poincarè section intersection. A grid search for an Earth to Venus transfer is presented as test case.     

ISO10012标准宣贯中的几个问题

简述了现行企业计量管理工作在宣贯ＩＳＯ１００１２标准中,遇到的主要问题及处理方法 。     

从国防计量认可复查看江西国防单位的计量工作

介绍江西国防科技工业单位的三级计量技术机构进行国防计量认可复查的情况 ,指出了存在的问题 ,并对问题的解决提出了建议     

空间目标编目测量资源调度策略设计与实现

空间目标编目测量资源调度是一个复杂的系统问题。首先对测量资源调度要素进行分析,然后在对调度需求分解的基础上,给出一个基于CSP（约束满足问题）模型的随机搜索编目调度算法。该算法在目标数量多、任务数据量大、复杂度高的任务环境下,求解快速、稳定。最后对调度软件实现中的核心问题——数据结构组织方式进行了阐述,基于合理的数据结构,调度算法得以高效实现。     

全测速多站系统的最优布站问题与数值算法

从解算弹道的逐点多站最小二乘算法得到的弹道精度出发,给出了一个全测速多站系统的最优布站数学模型,并通过大量试算选定了具有良好收敛性的数值算法.初步的计算表明：对全测速多站系统,其最优布站方案与现有布站方案在弹道精度上有着显著的差别;在最优布站方案下可确保逐点多站最小二乘算法具有良好的数值稳定性,并得到满足精度要求的外测弹道.     

大尺寸整体C/SiC复合材料蒙皮骨架松动问题分析

针对大尺寸整体C/SiC复合材料骨架和蒙皮结构在165 dB热噪声试验调试过程中出现的蒙皮松动问题进行分析,提出了蒙皮与骨架装配时空悬面积过大引起蒙皮呼吸振动幅度增加,从而导致噪声振动环境中蒙皮松动的现象.仿真分析表明,在相同的加速度激励下随着蒙皮与骨架局部空悬面积变大,位移响应增大约1.72倍;通过装配间隙为0.2、...     

对中国高模量碳纤维应用中工艺性能问题的分析

文章简述了航天器结构对高模量碳纤维需求,对中国高模量碳纤维品质稳定性、工艺稳定性等内容进行了简要评述,着重对中国高模量碳纤维工艺性能做了分析,并对加强中国高模量碳纤维批生产提出了建议.     

HBM—3000型门式布氏硬度计的调整与修理

介绍HBM－3000型门式布氏硬度计的电器控制系统的电器原理及手动与自动操作程序以及在调整与修理过程中发现的问题和解决的方法     

The gauge-generalized Gyldén–Meshcherskii Problem

The Gyldén–Meshcherskii Problem (GMP) extends the classical two-body problem of Newton and Kepler by considering time-varying gravitating masses, an important extension of the two-body problem for modeling cometary motion and cosmological phenomena. In this paper, we consider the GMP in a specialized setup, the setup of gauge theory. We show that the variational equations, modeling the effect of the mass time variation on the orbital elements, can be derived by fixing a gauge of a particular form that is different from the Lagrange gauge. Thus, the orbital elements modeling the effect of a time-varying secondary mass are non-osculating. This implies that the trajectory of a celestial body whose mass is continuously changing cannot be approximated by a series of Keplerian orbits. Finally, we provide the first-order averaged equations written in terms of non-osculating elements.     

卫星可见光遥感图像异常原因分析方法初探

随着中国高分辨率可见光遥感卫星数量日益增多，在轨卫星的图像品质和异常原因分析将成为今后一段时间相关研制人员关注的重点。文章列举了在轨可见光卫星的成像异常现象，分别对地面分辨率、对比度、信噪比和几何形变未能达标的原因进行了初步分析，提出了问题定位的初步方法。