Every now and then you may hear news of satellites sent into space. On Feb 21， 2022， for example， US company SpaceX took 46 satellites into orbit. A few days later， China sent 22 satellites into space. Why do we need so many satellites？ What do they do for us？

At present， there are more than 3，000 active satellites moving around the Earth， according to Statista， a German company that works on market data. Satellites have all kinds of roles， from transmitting TV signals， giving you directions on the road， to helping scientists with their research. For example， the 22 satellites China sent up are part of the BeiDou Navigation Satellite System. Shared bikes that use BeiDou chips can provide more accurate positioning， making them easier to find. Drones can also use BeiDou while flying.

你可能不時聽到關(guān)于衛(wèi)星被送入太空的消息。例如，2022年2月21日，美國太空探索技術(shù)公司SpaceX將46顆衛(wèi)星送入軌道。幾天后，中國向太空發(fā)射了22顆衛(wèi)星。我們?yōu)槭裁葱枰@么多衛(wèi)星？衛(wèi)星能為我們做什么？

據(jù)專門從事市場數(shù)據(jù)分析的德國公司Statista的數(shù)據(jù)顯示，目前有3000多顆有源衛(wèi)星在圍繞地球運行。衛(wèi)星有各種各樣的作用，從傳輸電視信號，到為你導(dǎo)航，再到幫助科學(xué)家開展研究。例如，中國發(fā)射的22顆衛(wèi)星就是北斗衛(wèi)星導(dǎo)航系統(tǒng)的一部分。可為安有北斗芯片的共享單車提供更精確的定位，也更容易讓人們找到。無人機飛行時也可以使用北斗系統(tǒng)。

Before satellites， TV signals didnt reach very far. Mountains or tall buildings would block the signals. Phone calls to faraway places were also a problem. Setting up telephone wires over long distances is difficult. With satellites， TV signals and phone calls can be sent directly to a satellite and back down to different locations on Earth. SpaceXs Starlink project is trying to go further. It plans to use satellites to provide people with Internet all over the globe.

Satellites can also provide information about clouds， oceans， land and ice. They help scientists predict changes in weather and climate. By monitoring wildfires and volcanoes， satellites help emergency workers deal with natural disasters. Farmers can use satellite images to decide the best time to water their fields.

Some satellites fly near other planets. They may look for water on Mars or take close-up pictures of Saturns rings. In 2020， video website Bilibili sent a satellite into space. Its job is to look at other planets and share the pictures and videos with Bilibilis users.

在有衛(wèi)星之前，因為高山或高樓會阻擋信號，電視信號沒法到達很遠的地方。給遙遠的地方打電話也是個問題，架設(shè)長途電話線十分困難。而有了衛(wèi)星，電視和電話信號可以直接發(fā)送到衛(wèi)星，然后傳到地球的不同位置。SpaceX的“星鏈”項目希望衛(wèi)星能起更大作用，該項目計劃利用衛(wèi)星向全球各地的人提供互聯(lián)網(wǎng)。

衛(wèi)星還可以提供關(guān)于云、海洋、陸地和冰的信息，以幫助科學(xué)家預(yù)測天氣和氣候的變化。通過監(jiān)測野火和火山，衛(wèi)星幫助緊急救援人員應(yīng)對自然災(zāi)害。農(nóng)民還可以利用衛(wèi)星圖像來判定灌溉農(nóng)田的最佳時間。

有些衛(wèi)星會在其他星球附近飛行。它們可以在火星上尋找水，也可以拍攝土星環(huán)的特寫照片。2020年，視頻網(wǎng)站嗶哩嗶哩將一顆衛(wèi)星送入太空。這顆衛(wèi)星負責(zé)觀察其他星球，并與嗶哩嗶哩用戶共享圖片和視頻。

Word Bank

orbit /'??b?t/ n. （天體等運行的）軌道

A new satellite has been put into orbit around the Earth.

transmit /tr?ns'm?t/ v. 傳送；輸送

drone /dr??n/ n. 無人駕駛飛機