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Orbiting the Earth
天上的卫星都在忙些啥？
Every now and then you may hear news of satellites sent into space.
你可能不时听到关于卫星被送入太空的消息。
On Feb 21, for example, US company SpaceX took 46 satellites into orbit.
例如，2月21日，美国太空探索技术公司（SpaceX）将46颗卫星送入轨道。
On Feb 27, China sent 22 satellites into space.
2月27日，中国向太空发射了22颗卫星。
Why do we need so many satellites?
我们为什么需要这么多卫星？
What do they do for us?
卫星为我们派上了哪些用场？
At present, there are more than 3,000 active satellites moving around the Earth,
目前有3000多颗活跃的卫星在围绕地球运行。
according to Statista, a German company that works on market data.
据专门从事市场数据分析的德国公司Statista的数据显示，
Satellites have all kinds of roles, from transmitting TV signals,
卫星有各种各样的作用，从传输电视信号，
giving you directions on the road, to helping scientists with their research.
到为你导航，再到帮助科学家开展研究。
For example, the 22 satellites China just sent up are part of the BeiDou Navigation Satellite System.
例如，中国刚刚发射的22颗卫星就是北斗卫星导航系统的一部分。
Shared bikes that use BeiDou chips can provide more accurate positioning, making them easier to find.
搭载北斗芯片的共享单车可以提供更精确的定位，也更容易让人们找到。
Drones can also use BeiDou while flying.
无人机飞行时也可以使用北斗系统。
Before satellites, TV signals didn’t reach very far.
在有卫星之前，电视信号没法到达很远的地方，
Mountains or tall buildings would block the signals.
因为高山或高楼会阻挡信号。
Phone calls to faraway places were also a problem.
给遥远的地方打电话也是个问题，
Setting up telephone wires over long distances is difficult.
架设长途电话线十分困难。
With satellites, TV signals and phone calls can be sent directly to a satellite and back down to different locations on Earth.
而有了卫星，电视信号和电话可以直接发送到卫星上，然后传回地球的不同位置。
SpaceX’s Starlink project is trying to go further.
美国太空探索技术公司的“星链”项目希望卫星能起更大作用，
It plans to use satellites to provide people with internet all over the globe.
该项目计划利用卫星向全球各地的人们提供互联网。
Satellites can also provide information about clouds, oceans, land and ice.
卫星还可以提供关于云、海洋、陆地和冰的信息，
They help scientists predict changes in weather and climate.
以便科学家预测天气和气候的变化。
By monitoring wildfires and volcanoes, satellites help emergency workers deal with natural disasters.
通过监测野火和火山，卫星帮助紧急救援人员应对自然灾害。
Farmers can use satellite images to decide the best time to water their fields.
农民还可以利用卫星图像来判定灌溉农田的最佳时间。
Some satellites fly near other planets.
有些卫星会在其他星球附近飞行。
They may look for water on Mars or take close-up pictures of Saturn’s rings.
这些卫星或是在火星上寻找水，或是拍摄土星环的特写照片。
In 2020, video website Bilibili sent a satellite into space.
2020年，视频网站哔哩哔哩将一颗卫星送入太空。
Its job is to look at other planets and share the pictures and videos with Bilibili’s users.
这颗卫星负责观察其他星球，并与哔哩哔哩用户共享图片和视频。
