In order to guarantee the characteristics of frozen orbit, in-plane orbit control needs to adjust the semi-major axis, eccentricity, argument of perigee simultaneously.

为了保证冻结轨道的冻结特性，平面内轨道控制需要对半长轴、偏心率和近地点幅角都控制。

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The semi-physical node controls the interface of Ethernet according to the satellite orbit and simulates the handoff of ISL, and so changes the topology of satellite network.

其中半实物仿真节点是自行设计的。 仿真节点根据卫星运行轨道通过控制以太网接口模拟卫星网络星际链路切换，改变网络拓扑结构。

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The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

第三定律（周期定律）：各个行星绕太阳公转周期的平方和它们的椭圆轨道的半长轴的立方成正比。

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The achievements include sending rovers to Mars, placing countless communication and imagining satellites in orbit, and the International Space Station, a semi-permanent home in space.

FORBES: Man in Space! 50 Years Later