9-14 用于探索太空的发明：人造卫星（在线收听）

Inventions for Exploring Space: Artificial Satellites

SputnikⅠwas the first artificial satellite. It can be described as an aluminium¹ sphere with a diameter² of 58 centimetres and weighing 83.6 kilograms, equipped with instruments to measure the temperature and the density of the atmosphere. SputnikⅠwas launched into orbit around the Earth by the former Soviet Union on 4 October 1957. Since then, hundreds of artificial satellites have been launched, each with a different function.

Some artificial satellites are used for telecommunications, which enable us to make telephone calls to any part of the world, to see live television transmissions³ and to communicate via the Internet. Other artificial satellites are used for navigation⁴, so that people on Earth can know at any moment the position of an object, within a few metres. Others are weather or meteorological⁵ satellites, launched to monitor the state of the atmosphere and to follow the movement of the clouds as they gather. There are also military satellites, for the purpose of gathering in formation on the armaments and the troops in countries which may be hostile and also to indicate the launch of a missile.

Each satellite has its own orbit which is selected according to its purpose. Communications satellites, for example, have a geostationary⁶ orbit. That is an orbit which turns at the same speed as the rotation of the Earth. Satellites used for weather forecasting pass over the two poles of the Earth. By so doing, a different part of the Earth’s surface is viewed on each successive⁷orbit. All artificial satellites get the energy they need by huge solar panels which extend like wings. These are therefore controlled in such a way that they are always turned toward the Sun.

注释：

1. aluminium [7Alju:5minjEm] a. [化] 铝的，铝制的

2. diameter [dai5AmitE] n. 直径

3. transmission [trAnz5miFEn] n. 播送，发射，发送

4. navigation [7nAvi5^eiFEn] n. 领航，导航

5. meteorological [7mi:tiErE5lRdVik(E)l] a. 气象的，气象学的

6. geostationary [7dVi(:)Eu5steiFEnEri] a. 与地球旋转同步的，对地静止的

7. successive [sEk5sesiv] a. 连续的，接连的

用于探索太空的发明：人造卫星

史普尼克1号是第一颗人造卫星。它可以被描述为一个直径58厘米、重83.6公斤的铝质球体，装备着用来测量大气温度和密度的仪器。该卫星是1957年10月4日由前苏联发射至环地球轨道的。从那以后，成百颗有着各种不同功能的人造卫星被发射升空。

有些人造卫星被用于通讯，使我们可以把电话打到世界任何一个角落，收看电视直播，并通过互联网交流。有些被用于导航，这样地球上的人便可以在任何时刻都能够知道一个物体的方位，其精确度达到几米以内。有些则是天气或气象卫星，发射升空用于监测大气状况，并在云层形成后跟踪其运动轨迹。此外，还有军事卫星，用于收集可能的敌对国的军事情报，还能在有导弹发射时发出信号。

每一颗人造卫星根据其不同目的选用不同的运行轨道。比如，通讯卫星有一个对地静止轨道。这种轨道是与地球自转保持同步的。用于天气预报的卫星的轨道会通过地球的两极。这样，地球表面的每一部分在卫星连续的轨道运行中都被一览无余。所有人造卫星都靠巨大的、仿佛翅膀一样展开的太阳能电池板获得能量。因此，它们被控制成总是面向太阳。