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91.
针对嫦娥二号探测器直接进入地月转移轨道、距月面100km高度捕获月球、完成既定任务后飞往日地第二拉格朗日平动点等飞行轨道方面的新特点,分析了定轨预报策略,利用事后精密轨道,全面评估了关键变轨点定轨预报和变轨后快速定轨的精度,其中,近月制动前3h定轨预报至近月点的位置误差为1km,速度误差为 0.3m/s 。利用不同月球引力场模型进行环月轨道精密定轨,根据实测数据残差分析和精密星历比对的结果,采用SGM100h引力场模型的定轨残差均方根最大。此外,针对嫦娥二号扩展任务,分析了不同测轨条件下的定轨精度,测量数据残差分析结果表明,在扩展任务中途修正前的定轨弧段内,测距、时延和时延率数据的残差分别为5m,5ns和1ps/s。 相似文献
92.
I.S. Veselovsky M.I. Panasyuk Yu.I. Yermolaev L.M. Zelenyi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
We briefly present the selected results obtained up to now by the Russian scientific groups regarding powerful solar ejections as main causes of large geomagnetic storms in the near-Earth space. Strongest perturbations on the Sun and in the near-Earth space responsible for large geomagnetic storms were well registered and analyzed during the 23rd solar cycle. Open issues and perspectives are discussed. 相似文献
93.
Pia Zacharias Sven Bingert Hardi Peter 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
We study extreme-ultraviolet emission line spectra derived from three-dimensional magnetohydrodynamic models of structures in the corona. In order to investigate the effects of increased magnetic activity at photospheric levels in a numerical experiment, a much higher magnetic flux density is applied at the photosphere as compared to the Sun. Thus, we can expect our results to highlight the differences between the Sun and more active, but still solar-like stars. We discuss signatures seen in extreme-ultraviolet emission lines synthesized from these models and compare them to observed signatures in the spatial distribution and temporal evolution of Doppler shifts in lines formed in the transition region and corona. This is of major interest to test the quality of the underlying magnetohydrodynamic model to heat the corona, i.e. currents in the corona driven by photospheric motions (flux braiding). 相似文献
94.
设计了一种新型的数字式太阳敏感器。采用SiP(Stystem in Package)设计,将滤光片直接安装于探测器上。此设计减小了数字式太阳敏感器的体积与质量,可提高其可靠性。所设计的数字式太阳敏感器可用于深空探测卫星系统的太阳捕获和太阳定向,同时,也可作为星上其他光电敏感器的监护仪器,防止其他光学敏感器被强光损坏。最后,完成了原理样机的研制与标定,并在外场进行了太阳光斑的拍图测试。实验表明所提出方法可行,可满足火星探测、深空探测的使用需求。 相似文献
95.
给出了椭圆暗条电流回路下暗条垂直平衡方程,并用它计算了NOAA131活动区暗条的平衡电流,分析了其暗条电流的特性. 相似文献
96.
本文对1989年4月9日与4B级大耀斑伴生的两个波段(3750 MHz,2840 MHz)的射电大爆发进行了简单的初步分析。结果表明:这两个波段的爆发不仅各自具有繁多的周期,而且都存在30+3s的准周期振荡。这种现象可能与磁环的准周期振荡有关,或与粒子流有关。 相似文献
97.
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99.
Franca Chiuderi Drago 《Space Science Reviews》1994,70(1-2):279-282
Different models of coronal streamers are used to calculate the radio brightness temperature at the wavelengths of observation of the Nançays Radioheliograph. Calculation are performed assuming the location of the streamer both on the disk and at the limb. Their comparison with observations show that a satisfactory agreement with a particular model can be found in the shape and in the relative enhacement of the streamer with respect to the quiet Sun, although the absolute values of the computed brightness temperatures are much higher than the observed ones. 相似文献
100.
A. A. Van Ballegooijen 《Space Science Reviews》1994,70(1-2):31-35
The formation of magnetic fine structures and associated electric currents is considered in the context of the coronal heating problem. The penetration of field-aligned electric currents into the lower atmosphere is discussed. It is argued that currents strong enough to heat the corona can persist only for short periods of time. The formation of thin current sheets is discussed. It is argued that photospheric magnetic structures (flux tubes) play an important role in the generation of coronal currents. 相似文献