The Earth's orbit is getting crowded. The past few years have witnessed huge growth in the number of satellites.

过去数年，随着卫星数量的剧增，地球轨道日趋拥挤。

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Solar power satellites that have been manufactured on the moon will have been placed in orbit around a number of planets and moons, providing nearby planetary outposts with continuous electric power.

由月球制造的太阳能人造卫星将被安置在许多行星及其卫星的轨道上，成为这些星球的观察站，并以太阳光为能源连续不断地工作。

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Together, these incidents increased the number of objects in orbit at an altitude of 700-1, 000km by a third (see chart).

这些事故及事件使离地700 - 1000公里的轨道上运行的太空物增加了三分之一(见图表)。

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The number of man-made objects in Earth orbit has been growing each year.

VOA: special.2009.04.01

n So the velocity is given by this product of the quantum number n Planck constant 2 pi mass of the electron time the radius of the orbit, which itself is a function of n.

速度是量子数,普朗克常数2π乘以轨道半径的值,它自身也是n的函数。

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The European Commission says the money will be needed beyond 2014 to raise the number of spacecraft in orbit to 30.

BBC: Galileo price rises 1.9bn euros

As technologies advance, he said, the Pentagon can reduce the number of drones in orbit, while still increasing the video, data and other information being transmitted.

NPR: Military Weighs Cutbacks, Shifts In Drone Programs

Besides spy satellites, Israel also has a number of communications satellites in orbit.

BBC: Israel launches Ofek 9 spy satellite