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This article studies the efficiency of ejecting waste generated by the life support system (LSS) of a manned spacecraft to reduce initial mass on low earth orbit. The spacecraft is used for a long-duration interplanetary mission and is equipped with either a chemical or a nuclear-thermal propulsion system. For this study we simulate an optimal control problem for a given spacecraft maneuver. An impulsive approximation of the optimal interplanetary spacecraft trajectory is assumed, which allows us to reduce the general optimal control problem to hierarchic structure of 'outer' and 'inner' subproblems. This structure is analyzed using the Pontryagin's Maximum principle. Numerical results, illustrating the efficiency of waste ejection are shown for typical Earth-Mars transfer trajectories. This results confirm in theory that using a waste ejection system makes an early manned Mars mission possible without having to design and build new, advanced biological LSS. 相似文献
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本文从控制理论的观点探讨了分析了惯性导航系统(INS),提出并了线性误差模型,计算了几种特殊情况下的特征值,表明推导特征值的准确表达式和通常采用的表达式稍有不同,分析了INS在静态初对准和标定过程中的可观测性,引入了基于物理本质的变换,能较容易地用检验新的动态矩阵来确定不可观测子空间及状态变量,最后提出了系统可观测性与估计量的特性之间的关系。 相似文献
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微镜单元的设计与加工工艺研究 总被引:1,自引:0,他引:1
详细介绍了微光学电子机械系统MOEMS领域的用于光学信号调制的微镜单元,分析了该微镜单元的工作原理及结构,推导了动态方程的有关参数,给出了仿真结果。首次提出了该结构前两阶频率的表达式,并与相应的有限元模态分析结果进行了比较。本文还对微镜的加工工艺作了简要介绍。 相似文献
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At present the main trends among the most important problems of otorhinolaryngology in space medicine have become defined as vestibulology, audiology and clinical aspects (prophylaxis, diagnosis and treatment of ENT diseases in flight). The principal result of recent vestibular studies has probably been the establishment of an apparent relationship between the resistance of the vestibular system to adequate ground-based stimulation and tolerance to space flight. The findings of the studies formed the basis for the development of a new system of vestibular selection, as well as demonstrated the usefulness of special vestibular training of astronauts by active and passive methods. In audiology certain urgency is acquired by the problem of noise limitation in space cabins and auditory system reliability prediction for preserving a high work capability in crew members. The hemodynamic changes in weightlessness, as well as the possibility for allergic lesions, create conditions for distorted course of the ENT diseases and vaso-motor disorders. The prophylaxis of aspirations also deserves close attention since the possibilities of their onset increase in weightlessness. The rendering of immediate, timely aid will depend not only on the presence of the necessary medical equipment but also on the ability of the crew members to render the appropriate otorhinolaryngological aid. 相似文献
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本文提出了用Bar-Itzhack和Berman误差模型对惯性导航系统(INS)地面对准的可观测性进行系统分析,指出了不可观测状态变量可分别包含在两个解耦子空间中,讨论了选择不可观测状态变量的限制,为计算不对准角,提出了全部由水平速度输出导出的一种估计算法。揭示了方位误差可以完全由水平误差和水平误差率的估值来估计,而完全不依赖于陀螺输出信号。 相似文献
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本文提出了以傅立叶级数分析的为基础将飞行试验数据方面的信号和噪声分开的技术,在频率域内用设计的最优滤波器完成此项工作,该方法以测量时间历程的谱范围为基础使信号和噪声分开,模拟数据用来说明此项技术及评价估计噪声特征的准确性,对20种模拟情况,估计噪声标准误差在真实值的5%以内,此外分析了从F-18大α角研究机的横侧机动飞行中获得飞行试验数据,理论分析表明,对模拟数据和飞行试验数据,该技术都是可信的。 相似文献
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