1·Why is space junk considered a problem?
为什么太空垃圾被认为是一个问题？
2·Many scientists are also suggesting different ways to clean up space junk.
许多科学家也提出了清理太空垃圾的不同方法。
3·In England, scientists are testing metal net that can be fired into space junk.
在英国，科学家们正在测试可以被发射到太空垃圾中的金属网。
4·According to BBC News, there are more than 22,000 pieces of space junk floating around the earth.
据 BBC 新闻报道，有超过22000块太空垃圾漂浮在地球周围。
5·The Germans are building robots that can collect pieces of space junk and bring them back to Earth to be safely destroyed.
德国人正在制造能够收集太空垃圾碎片并将其带回地球安全销毁的机器人。
6·For example, when a satellite hit an old Russian rocket in 2009, it broke into more than 2,000 pieces, increasing the amount of space junk.
例如，2009年，一颗卫星撞上了一枚俄罗斯旧火箭，它碎成了2000多块碎片，增加了太空垃圾的数量。
7·Space junk is dangerous.
太空垃圾极其危险。
8·Have you ever seen some space junk with your own eyes?
你在空间站亲眼眼看到过太空垃圾吗？
9·A four-inch piece of space junk can demolish a shuttle.
一片四英尺的太空垃圾可以摧毁一架航天飞机。
10·Pf : Probability that a piece of space junk will survive reentry.
Pf：指一块太空垃圾坠落到地球表面的概率。