Analysis of tape tether survival in LEO against orbital debris

The low earth orbit (LEO) environment contains a large number of artificial debris, of which a significant portion is due to dead satellites and fragments of satellites resulted from explosions and in-orbit collisions. Deorbiting defunct satellites at the end of their life can be achieved by a successful operation of an Electrodynamic Tether (EDT) system. The effectiveness of an EDT greatly depends on the survivability of the tether, which can become debris itself if cut by debris particles; a tether can be completely cut by debris having some minimal diameter. The objective of this paper is to develop an accurate model using power laws for debris-size ranges, in both ORDEM2000 and MASTER2009 debris flux models, to calculate tape tether survivability. The analytical model, which depends on tape dimensions (width, thickness) and orbital parameters (inclinations, altitudes) is then verified with fully numerical results to compare for different orbit inclinations, altitudes and tape width for both ORDEM2000 and MASTER2009 flux data.     

基于航线对象的五边进近调配程序模型研究

针对进近管制飞行密集、潜在冲突多、调配难度大的特点,提出一种智能化的调配程序研究方法。将五边调配程序分解为基本的飞行程序,并引入航线对象的概念,结合五边进近飞行特点建立调配程序的参数模型。通过模型计算得到关键位置点及飞行控制参数信息,同时生成飞行路径,综合全部信息即得到完整的调配方案,能够为实际管制工作提供参考和服务。计算机仿真结果证明了理论方法的可行性。     

The dynamics and control of the CubeSail mission: A solar sailing demonstration

The CubeSail mission is a low-cost demonstration of the UltraSail solar sailing concept (, ,  and ), using two near-identical CubeSat satellites to deploy a 260 m-long, 20 m² reflecting film. The two satellites are launched as a unit, detumbled, and separated, with the film unwinding symmetrically from motorized reels. The conformity to the CubeSat specification allows for reduction in launch costs as a secondary payload and utilization of the University of Illinois-developed spacecraft bus. The CubeSail demonstration is the first in a series of increasingly-complex missions aimed at validating several spacecraft subsystems, including attitude determination and control, the separation release unit, reel-based film deployment, as well as the dynamical behavior of the sail and on-orbit solar propulsion. The presented work describes dynamical behavior and control methods used during three main phases of the mission. The three phases include initial detumbling and stabilization using magnetic torque actuators, gravity-gradient-based deployment of the film, and steady-state film deformations in low Earth orbit in the presence of external forces of solar radiation pressure, aerodynamic drag, and gravity-gradient.     

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。     

一种机载软件安全性需求获取方法

通过对国内外软件安全性分析方法的研究,结合国内软件开发技术和管理方法,探索并提出了一种机载软件安全性需求获取方法。并以某环控防冰系统监测软件为例,给出了软件安全性需求获取方法的应用实例。     

飞机保障设备发展现状及建议

航空保障设备是综合保障要素之一,是战斗能力形成的重要支撑。本文介绍了国外保障设备发展趋势,分析了我军面临的主要问题:保障设备需求论证不充分,研制流程不规范,"通用化、系列化、模块化"程度低,缺乏全寿命周期的数据信息分析共享等,提出了飞机保障设备发展措施与建议,可作为我军保障设备未来发展的参考。     

缓冲气囊展开与缓冲着陆过程的仿真分析

文章基于显式有限元模型,采用控制体积法对缓冲气囊的展开及缓冲过程进行仿真分析。首先对单个球形气囊进行折叠展开过程模拟,之后依据NASA"猎户座"缓冲着陆器的缩比模型,建立了一个用以评估气囊着陆衰减系统的LS-DYNA有限元模型。分别研究了缓冲着陆器正碰和侧碰对缓冲气囊压力、着陆器的加速度和运动的影响。并与文献进行对比验证,计算结果表明数值模拟的正确性。     

Orbit Design for Responsive Space Using Multiple-objective Evolutionary Computation

Responsive orbits have exhibited advantages in emergencies for their excellent responsiveness and coverage to targets. Generally, there are several conflicting metrics to trade in the orbit design for responsive space. A special multiple-objective genetic algorithm, namely the Nondominated Sorting Genetic Algorithm Ⅱ (NSGAⅡ), is used to design responsive orbits. This algorithm has considered the conflicting metrics of orbits to achieve the optimal solution, including the orbital elements and launch programs of responsive vehicles. Low-Earth fast access orbits and low-Earth repeat coverage orbits, two subtypes of responsive orbits, can be designed using NSGAⅡ under given metric tradeoffs, number of vehicles, and launch mode. By selecting the optimal solution from the obtained Pareto fronts, a designer can process the metric tradeoffs conveniently in orbit design. Recurring to the flexibility of the algorithm, the NSGAⅡ promotes the responsive orbit design further.      

一种综合通信导航识别系统的多波形部署方案设计

针对拥有多个相同任务通道的综合通信导航识别系统的多波形部署问题,提出了一种采用静态策略 的多通道多波形部署设计方案。本方案基于软件通信体系结构设计,实现了多波形应用与多个任务通道的匹配 机制和根据静态策略在多个任务通道上部署波形的机制。     

一种新的升力式再入投送系统轨道部署方法

针对天基再入投送系统与传统星座轨道部署问题的不同,建立了用于轨道部署覆盖性能仿真的星下点轨迹、覆盖条带计算模型和覆盖判别条件模型;针对传统部署方法的不均匀性,提出了一种新的升力式再入飞行器全球部署方法。该方法采用双倾角条带覆盖方式克服了传统部署方法的固有缺陷,既实现了全球覆盖又提高了重点区域的覆盖重数。仿真结果表明该部署方法的覆盖性能相对传统方法有明显提高,在满足全球100%覆盖的同时又对重点区域的覆盖重数提高了约20%,覆盖性能优异。