Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polarorbiting Iridium satellite.
峰顶正上方是明亮的北极星，这次曝光正好逮住了一颗极轨铱星的闪光。
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This paper studies magnetic control of polarorbiting, nadir pointing satellite.
本文研究如何用磁力矩器控制极地轨道上对地指向卫星的姿态。
3
The magnetic control system for polarorbiting, nadir pointing small satellite is studied in this paper. It is shown that the dynamics with magnetic control system is a linear periodic system.