共查询到20条相似文献,搜索用时 15 毫秒
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Aleksashkin S. N. Bobylev A. V. Vlasenko O. V. Pichkhadze K. M. Terterashvili A. V. Yaroshevsky V. A. 《Cosmic Research》2003,41(3):280-284
The possibility of using an inflatable braking device for controlled descent in the Martian atmosphere of large-capacity cargoes is analyzed. The most complicated version of the trajectory control problem is considered, namely, the injection of a spacecraft at hyperbolic velocity into a parking orbit after braking in the atmosphere. 相似文献
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M. Yu. Zabolotnov 《Cosmic Research》2003,41(2):171-177
An analysis of the stability of the resonance motion of a spacecraft with a small asymmetry during its descent in the atmosphere is carried out. In the vicinity of the main resonance, the action–angle variables are introduced and an equation of the variation of action is composed. A conclusion related to the stability of the resonance motion is made from the investigation of this equation. Sufficient conditions of stability of the resonance motion of a spacecraft are obtained and represented in a form convenient for analysis. 相似文献
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提出了一种火星再入探测器的半解析法一体化模型,为未来火星探测器的初步设计提供包括弹道、气动参数、防热系统在内的设计依据。在任务初步设计阶段,由于涉及多个学科,火星大气与地球大气模型差异很大,需要考虑的因素很多,因此需要一个半解析的,能够实时进行弹道、气动参数和防热层温度分布计算的设计工具。该工具应该包括气动外形、弹道、防热为一体的设计模型,且能满足计算负担要求。基于此,提出了一种普遍适应的火星探测器外形定义方程,并对其中的一种特殊情况进行了解析公式的推导。在合理假设的前提下,给出了计算防热层内部温度分布的半解析计算公式,并以MER\|B (Mars Exploration Rover)探测器为例进行了弹道和气动受热仿真。计算结果表明,该一体化计算模型的仿真计算落点与实际落点很接近,达到了火星探测器初步设计阶段一体化的计算要求。
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The estimation of the probability of capture into a resonance mode of motion is considered for a spacecraft with a small asymmetry during its entry into the atmosphere. It is assumed that the initial conditions of spacecraft motion are distributed uniformly in some sufficiently small domain. The problem is solved for the equations of spacecraft motion linear with respect to the angle of attack. An analytical estimate of the probability of the spacecraft capture into the resonance corresponding to an ascending branch of the velocity head is obtained. The emphasis in the analysis of the estimate is made on the effect of the spacecraft asymmetry type on the probability of capture. A comparison of the estimate with the results of numerical computation is carried out. A model problem concerning the construction of the domain of the spacecraft center of mass locations, most dangerous from the point of view of the realization of the stable resonant modes of motion, is solved. 相似文献
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针对火星和地球大气分子热力学和化学行为的差异性,采用理论分析和数值模拟两种手段,研究探测器进入过程高超声速流动的分子振动激发、离解反应及热力学和化学非平衡等真实气体效应,获得不同气体模型条件下的高超声速气动加热规律,探究引起地火差异的根本原因。分析认为,探测器进入火星大气层的稀薄气体效应明显;激波层内发生CO 2气体为主的大规模离解,在极高温环境下O 2和CO也将离解;沿进入轨道的高超声速流动基本处于化学非平衡但热力学平衡状态;激波层内能量储存和分配模式因分子振动激发和化学反应而改变,分子振动激发会增强气动加热量,但均介于化学反应模型的完全非催化和完全催化壁结果之间;相同来流条件下CO 2介质高超声速气动加热强于空气介质,但真实的火星进入热载荷因大气稀薄而弱于地球再入环境。相关研究为我国未来火星探测器热防护系统设计提供技术支持。 相似文献
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An analysis of the typical external factors of a forecasting background is performed for the case when these factors affect the operation of onboard maintenance systems of low-orbit satellites. Taking into account the formulated requirements for the method of forecasting spacecraft characteristics, we have substantiated and tested a neural network prognostic model. 相似文献
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The separation of motions into slow (precession) and fast (nutation) components in the problem of the entry of a spacecraft (SC) with a small asymmetry into the atmosphere is considered. For the separation of the slow and fast motions the method of integral manifolds is used together with the asymptotic method for singularly perturbed systems. The separation of motions allows one to isolate the frequencies that are functions of the slow variables of a system, and further on, after determining the integer relations between them, to construct the resonant curves (surfaces). This method gives the possibility to analyze the conditions of the emergence of resonances for a SC at angles of attack that are not small and when aerodynamic characteristics are nonlinear. Examples of the construction of resonant curves for a SC with typical aerodynamic characteristics are considered. 相似文献
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再入航天器防热层/金属结构热匹配评价方法研究 总被引:1,自引:0,他引:1
概述了在轨温度交变环境下再入航天器防热层/金属结构热匹配的3种评价方法———温度交变试验、热应力理论计算和有限元模型分析。结合工程实际,介绍了3种方法的应用情况和应用特点:温度交变试验可以定性研究温度交变环境及胶层厚度对结构热匹配特性的影响;热应力理论计算能够在一定程度上量化结构热应力等结果;有限元模型分析可以获得结构任意时刻、任意位置的热应力与热变形的量化数据,具有较大的应用优势。通过对比分析,建议采用温度交变试验与有限元模型分析相结合的方法,以实现防热层/金属结构热匹配特性的准确评价,最终验证防热结构方案设计的合理性。 相似文献
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The motion of a spacecraft with small asymmetry relative to its center of mass is considered. The restoring aerodynamic moment of the spacecraft is described by the Fourier series in terms of the angle of attack with the two first sinusoidal and the first cosinusoidal terms. A solution for the angle of attack in the undisturbed rotational motion is found. The analytical expression is obtained for the integral of action taken along the separatrices that separate the rotational and oscillatory regions of the phase portrait of a system. The transition of the spacecraft's motion from planar rotational to oscillatory is investigated. This transition is caused by a slow variation of moment characteristic coefficients, as well as by the presence of small asymmetry and damping and slow variation of their coefficients. Analytical formulas are obtained for determining the times of transition from rotational to oscillatory motion, as well as for the critical angular velocity of beyond-the-atmosphere rotation. When this critical velocity is exceeded, body rotation proceeds for a long time interval (planar autorotation arises). 相似文献
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The conceptual and methodological principles, as well as some results of the comprehensive substantiation of a technical approach at early stages of design of power-propellant systems (PPS), are presented. By the PPS of a spacecraft is meant a set of devices for production, transformation, and distribution of energy onboard orbital vehicles. The element-stream matrix is suggested to be used as a rational form of representing the PPS structure. 相似文献
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Initial orbital parameter errors are used to examine the miss distance between a spacecraft and an ensemble of tracked objects by a Monte Carlo-type analysis. The radial separation between orbits is evaluated and a keep-out zone is determined, which reduces the risk of collision to an acceptable level.An operational prediction methodology is suggested based on a catalog database, which identifies potentially hazardous approaches and computes the probability of collision for selected spacecraft. An example for the Mir Space Station is presented, which estimates the collision probability and the cross-sectional flux of cataloged objects for the time frame of interest. The results appear to be in good agreement with those of other space debris models. 相似文献
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空间飞行器大角度机动控制律设计 总被引:1,自引:1,他引:1
研究了空间飞行器大角度机动控制问题。为避免欧拉角描述姿态运动存在奇异性的问题,由姿态四元数建立姿态运动方程。针对飞行器姿态运动模型的非线性和不确定性,利用模糊逻辑系统对不确定性函数进行逼近,将获得的模糊函数作为系统不确定性界函数。对模糊逼近所带来的误差以及外部干扰项,采用变结构补偿控制方法,并在线自适应调整参数。理论分析和仿真研究表明此方法具有姿态控制精度高,实时计算量小,便于工程实现等优点。 相似文献
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针对火星稀薄大气环境的不确定性对进入器气动特性的影响问题,先以海盗号火星进入器的飞行试验数据对发展的三维并行直接模拟蒙特卡罗(DSMC)仿真软件进行了算例校验,再以火星科学实验室外形为例,计算气体组分、密度、温度及速度等来流参数的不确定性对进入器气动特性的影响偏差,定性定量给出火星高空稀薄环境下大气不确定性所带来的气动力特性规律。研究结果表明,通过与海盗号飞行实验数据的对比校验了所建立方法的正确性与可靠性;CO2大气环境对进入器气动特性的影响较大,利用空气稀薄环境中的计算及实验结果亦需进行CO2效应修正,这一点与连续流区的结论一致;来流密度及速度的不确定性对气动力、力矩特性均有影响,而来流温度影响的最大偏差小于0.5%;纵向压心对来流密度、温度及速度的扰动均不敏感。 相似文献
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在轨服务航天器对失控航天器参数估计算法研究 总被引:1,自引:0,他引:1
为获取空间失控航天器运行参数,采用单目视觉在服务航天器上进行在轨参数估计.对于非合作目标航天器以其外形特征直线为观测对象,采用对偶四元数描述相对位置和姿态,建屯视觉相机观测模型和目标器相对运动模型,并以这些模型为基础,以位置、姿态及惯量比为估计变量,推导适合IEKF形式的系统状态方程和观测方程.IEKF虑波在虑波周期内能够对状态更新信息进行多次迭代,进而减少了观测方程线性化引起的误差,确保了整个虑波估计的收敛稳定.最后进行了相关算法的数学仿真,仿真结果表明采用文中设计的虑波算法能够实现相应参数的在轨估计. 相似文献
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