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1.
潜在威胁小行星碰撞防御的计算与分析   总被引:1,自引:1,他引:0  
研究了采用碰撞的方式进行小行星防御的动力学问题。采用多面体模型来建立小行星的外形模型,以碎石堆模型来建立小行星的结构模型,计算了小行星受到与其密度和材质相同的球体高速碰撞过程和碰撞后的碎石分布。计算过程在考虑了小行星与碰撞球体的接触形变以及小行星内部组成碎石堆的接触形变条件下,计算了碎石堆内部的相互引力、法向接触力、切向静摩擦力、切向动摩擦力和滚动摩擦力矩。以小行星101955 Bennu(中文名贝努)为对象计算了潜在威胁小行星的碰撞防御过程的动力学行为。结果显示:采用高速碰撞的方法进行小行星防御可以有效地将小行星撞成大量碎小的石块,且该方法具有核爆的方法不可比拟的优势,即对空间环境无污染。  相似文献   

2.
<正>5月初,在美国马里兰州召开的第六届行星防御会议上进行了一场小行星防御演习。美国宇航局下属喷气推进实验室虚构了一颗可能在2027年4月29日撞击地球的小行星(代号2019PDC),由来自美国宇航局、美国联邦应急管理局、欧空局等机构的专家团队负责迎战小行星,以拯救人类。最后的结果是,虽然人类采用动能撞击法将2019PDC号小行星撞碎,但一块60米左右的碎块仍在飞向地球,  相似文献   

3.
为了评估空间碎片超高速撞击航天器的碎片云破坏能力,挖掘超高速撞击数值模 拟结果数据的应用价值,基于9.53mm铝球以6.64km/s速度对2.2mm铝靶撞 击的Ls-Dyna/SPH(Smoothed Particle Hydrodynamic)数值模拟研究结果,对靶后碎片云的 粒子动能进行求和统计,建立了碎片云比动能概念和函数形式;碎片云比动能综合考虑了靶 后所有碎片云粒子的动能,反映了一定距离处垂直于撞击方向平面上单位面积上的碎片云粒 子所蕴含的撞击能量;应用碎片云比动能概念,揭示出随着演化距离的增加,碎片云能量的 衰减规律;通过不同速度条件下的SPH计算,得到了碎片云的比动能函数的曲线形式随撞击 速度的变化规律;最后对采用2种材料模型进行数值模拟所对应的结果误差进行碎片云比动 能函数的曲线比较,反映出数值模拟中不同材料模型引起的差异.  相似文献   

4.
动量传递因子β是评估动能撞击效果的重要参量。根据动能撞击过程中动量传递因子的理论模型,分析了撞击器特性参数和小天体结构特性参数对动量传递因子取值的影响,并对不同动能撞击方案以及不同材料特性小天体的成坑效应和动量传递因子进行分析。研究表明:标度律参数μ对β影响较大,μ是地面实验拟合得到的系数,与材料强度特性相关;当小天体为单体岩石结构时,撞击器速度及密度、小天体密度及表面强度对β影响较大,而撞击器半径和小天体引力对β影响较小;当小天体为碎石堆结构时,β对撞击器特性参数和小天体特性参数不敏感,且数值较小。对三种不同动能撞击方案的成坑效应与动量传递因子形成规律进行研究,发现撞击器初始动能对β影响较大。当小天体为单体岩石结构时,其对应的动量传递因子取值较大,而当小天体为碎石堆结构时,其对应的β取值较小且基本不变。对相同动能撞击方案下不同材料特性小天体(C型、S型和X型小行星)产生的撞击效应进行分析,发现在引力主导时,βC>βS>βX,而在强度主导时β取值较小且基本相同。  相似文献   

5.
正目前,美国航空航天局公布了DART任务的最新进展,计划发射一艘太空飞船高速碰撞具有潜在威胁的小行星,并改变它的运行轨迹。美国航空航天局行星防御官员林德利·约翰逊说,DART是美国航空航天局证实“动能撞击器技术”的第一项太空任务,届时,太空飞船碰撞小行星的速度是5.9千米/秒,是子弹速度的9倍以上。  相似文献   

6.
近年来,各国针对近地小行星的威胁及相应防御策略的研究越来越多。调研了国内外近地天体观测发展现状和多种近地小行星撞击地球的防御策略,通过比较分析防御策略的实现原理、关键技术和存在的问题,对各种策略的适用性、可行性和有效性进行了评估。通过对各种策略的分析和总结,结合我国近地小行星防御策略的研究现状,尝试性提出了采用多种策略组合的方式对有潜在威胁的小行星采取相关有效方案,为航天器的研制和防御策略的实施争取更多的时间。  相似文献   

7.
航天器微流星体及空间碎片环境与风险分析   总被引:1,自引:0,他引:1  
微流星体及空间碎片的高速撞击威胁着长寿命、大尺寸航天器的安全运行,导致其严重的损伤和灾难性的失效。文章对低地球轨道微流星体及空间碎片环境进行了分析,给出了微流星体及空间碎片对航天器威胁方向的确定方法,得到了空间碎片撞击航天器相对撞击角的概率分布以及地球对微流星体遮挡的影响。编制了风险分析软件,以采用单防护屏防护结构的柱状低地球轨道航天器为例进行风险分析。  相似文献   

8.
根据俄应用天文学研究所提供的数据目前有约400颗小行星和30多颗彗星对地球构成潜在威胁,10月24日,俄罗斯联邦航空航天局副局长列米舍夫斯基称,俄已做好“在必要时”驱走威胁地球的小行星的准备。必要时,俄火箭制造部门可实施太空手段来赶走威胁地球的小行星。他强调,拯救受小行星威胁的地球需要国际合作,要能就小行星撞击威胁进行预警。  相似文献   

9.
正自从人类认识到近地小行星(NEA)的撞击危险性以来,一直在思考如何减轻和避免小行星撞击地球带来的灾害,并提出了许多应对措施。从不同的角度出发,可以将这些措施分成几种类型。按对撞击者处理方式不同,可分为偏转小行星的轨道和击碎小行星两种方式;按使用的能源不同,可分为动能、电磁能、引力、太阳能以及核能等方式;按接近小行星的方式不同,可分为拦截、轨道交会等方式;根据是否能快速地向目标传递能量,还可以分为直接和间接两种方式。究竟采取何种方式,要根据撞击可能发生的时间、撞击者的大小和轨  相似文献   

10.
数量庞大的近地小行星对地球安全构成了重大潜在威胁,受现阶段小天体观测技术水平限制,仍有大量危险性小行星尚未发现。瞄准我国近地小行星空间观测技术发展需求,通过综合分析国内外近地小行星观测现状及相关技术水平,并结合天/地基小行星观测平台能力对比,从我国近地小天体观测技术基础出发,提出了我国空间红外小行星观测技术方案。采用可见–红外融合探测的技术方案开展小行星搜寻与光谱详察,并通过空间小行星观测平台与地面观测装备网络协同观测,为推动形成我国天体一体化小行星观测体系奠定基础;同时通过对多种小行星撞击地球的防御策略以及小行星利用价值综合分析,为我国开展近地小行星观测、预警、防御等任务提出了初步建议。  相似文献   

11.
The asteroid and cometary impact hazard has long been recognised as an important issue requiring risk assessment and contingency planning. At the same time asteroids have also been acknowledged as possible sources of raw materials for future large-scale space engineering ventures. This paper explores possible synergies between these two apparently opposed views; planetary protection and space resource exploitation. In particular, the paper assumes a 5 tonne low-thrust spacecraft as a baseline for asteroid deflection and capture (or resource transport) missions. The system is assumed to land on the asteroid and provide a continuous thrust able to modify the orbit of the asteroid according to the mission objective. The paper analyses the capability of such a near-term system to provide both planetary protection and asteroid resources to Earth. Results show that a 5 tonne spacecraft could provide a high level of protection for modest impact hazards: airburst and local damage events (caused by 15–170 m diameter objects). At the same time, the same spacecraft could also be used to transport to bound Earth orbits significant quantities of material through judicious use of orbital dynamics and passively safe aero-capture manoeuvres or low energy ballistic capture. As will be shown, a 5 tonne low-thrust spacecraft could potentially transport between 12 and 350 times its own mass of asteroid resources by means of ballistic capture or aero-capture trajectories that pose very low dynamical pressures on the object.  相似文献   

12.
Modern techniques for planetary defense from comets and asteroids involve the deflection of the bolide via kinetic, gravitational, ablative, or radiative means. While potentially effective, none of these methods are capable of operating in a terminal interdiction mode wherethe threat is discovered with little time prior to impact. We present a practical and effective method for planetary defense which enables extremely short interdiction time scales, but can also operate within longer time scales and can be effective for extremely large threats. Called PI (“Pulverize It”), the method makes use of an array of hypervelocity penetrators which uses the kinetic energy of the asteroid or comet to disrupt it. In the terminal interdiction mode, the fragments of maximum 10 m diameter disperse laterally as they continue towards the Earth, and then enter the Earth’s atmosphere where they burn up as a series of airburst events which spatially and temporally de-correlate the energy of the original parent bolide for any arbitrary observer on the ground in the form of acoustical shockwaves and optical pulses. We show that terminal interdiction modes ranging from 2 minutes prior to impact for 20-meter class bolides (such as the Chelyabinsk asteroid), 1 day prior to impact for 100 m-class asteroids, 10 days prior to impact for Apophis-class asteroids (370 m), and even 60 days prior to impact for 1 km-class threats are all possible, though longer warning times are always preferred. Using only technologies readily available today, the PI method allows for a cost-effective and practical roadmap towards robust planetary defense capability.  相似文献   

13.
Asteroid deflection techniques are essential in order to protect the Earth from catastrophic impacts by hazardous asteroids. Rapid design and optimization of low-thrust rendezvous/interception trajectories is considered as one of the key technologies to successfully deflect potentially hazardous asteroids. In this paper, we address a general framework for the rapid design and optimization of low-thrust rendezvous/interception trajectories for future asteroid deflection missions. The design and optimization process includes three closely associated steps. Firstly, shape-based approaches and genetic algorithm (GA) are adopted to perform preliminary design, which provides a reasonable initial guess for subsequent accurate optimization. Secondly, Radau pseudospectral method is utilized to transcribe the low-thrust trajectory optimization problem into a discrete nonlinear programming (NLP) problem. Finally, sequential quadratic programming (SQP) is used to efficiently solve the nonlinear programming problem and obtain the optimal low-thrust rendezvous/interception trajectories. The rapid design and optimization algorithms developed in this paper are validated by three simulation cases with different performance indexes and boundary constraints.  相似文献   

14.
近地小行星交会、绕飞、着陆与采样返回技术经过数10年的发展日趋成熟。美国的OSIRIS-Rex对C类小行星进行特征分析与采样,日本宇宙航空研究开发机构的“隼鸟-2号”任务目的是小行星深层采样。美国国家航空航天局(NASA)和欧洲空间局(ESA)的小行星探测任务开始转向行星防御领域。NASA的ARM(Asteroid Redirect Mission)计划是开展小行星抓捕与轨道重定向,ESA联合NASA提出了小行星撞击与偏转评估计划,拟对双星系统开展撞击实验,为行星防御提供技术积累。此外,行星资源公司和深空工业公司分别规划了小行星商业采矿的蓝图,并已开展相关的在轨技术验证。对近地小行星的探测历程进行了回顾,重点介绍了OSIRIS-Rex、“隼鸟-2号”、NASA和ESA的行星防御计划及小行星采矿公司的商业采矿战略规划,总结了未来开展行星防御与采矿的关键技术。  相似文献   

15.
The lifetime of almost all the asteroids against catastrophic impact events is less than the age of the solar system, implying that the asteroids can be considered as outcomes of catastrophic collisions. Therefore to understand their physical properties (structure, shape, rotation, regolith development) and their family memberships (since families are generated by the escape of breakup fragments), a systematic knowledge of the outcomes of catastrophic impacts under a variety of conditions seems needed. In particular, interesting fields to be explored by laboratory experiments are: the dependence of the critical energy densities associated with various degrees of fragmentation on the target's size and composition; the velocity distribution of the fragments and the inelasticity of the process in different cases; the shape of the fragments and its possible correlation with other quantities; the way a dust- or regolith-covered target affects the collisional outcomes; the angular momentum partitioning and the rotation of the fragments. On this latter problem very few experimental results are presently available; on the other hand, the rotation of small asteroids presents several intriguing “anomalies”.

A significant progress of our understanding of asteroid collisional evolution and related phenomena can be provided by new laboratory experiments of collisional breakup. The targets should have spherical and/or irregular shape (up to axial ratios of the order of 2), and should be made of (possibly different) geological materials. The interesting projectile velocities are of the order of the relative velocities commonly found among asteroids, i.e., in the range 1 to 10 Kms−1. In order to get catastrophic collisions, the ratio of the projectile kinetic energy to the target mass (≡E/M) has to be chosen within a “critical” range (for basalt targets, from 106 to 108 erg/g). In some particular cases, this kind of experiments has been already performed in past (Gault and Wedekind [10]; Fujiwara et al. [7]; Fujiwara and Tsukamoto [9]); however the generalization of the results to a wide range of experimental conditions is lacking, and many problems of outstanding importance to model asteroid evolution are still completely open.  相似文献   


16.
This paper presents the design of a multi-spacecraft system for the deflection of asteroids. Each spacecraft is equipped with a fibre laser and a solar concentrator. The laser induces the sublimation of a portion of the surface of the asteroid, and the resultant jet of gas and debris thrusts the asteroid off its natural course. The main idea is to have a formation of spacecraft flying in the proximity of the asteroid with all the spacecraft beaming to the same location to achieve the required deflection thrust. The paper presents the design of the formation orbits and the multi-objective optimisation of the formation in order to minimise the total mass in space and maximise the deflection of the asteroid. The paper demonstrates how significant deflections can be obtained with relatively small sized, easy-to-control spacecraft.  相似文献   

17.
近地小行星与地球碰撞虽然罕见但可能会造成灾难性后果。近年来,各国加强了对近地小行星的监控、跟踪力度,并且实施了几次卓有成效的探测任务,如何防御近地小行星威胁的研究越来越多。总结了目前近地小行星的主要观测监视设施和现状,讨论了国际上对小行星威胁的评估情况,分析和评估了目前提出的防御手段的研究现状及其可行性。  相似文献   

18.
A kinetic impact occurs when an asteroid is moving. The impact may be caused by other small celestial body or an artificial object. Ejecta is produced from an impact. Dynamics of ejecta near a binary system which contains an ellipsoid and a sphere is analyzed. A phase diagram which comes from numerical simulation is shown in this work. The phase diagram shows a clear structure. Some special trajectories are also shown, which indicates a potential source of asteroid orbiting objects.  相似文献   

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