By Jason Palmer, BBC News

媒體英語會帶大家一起學習 BBC 撰稿人在報道世界大事時常用到的單詞和短語。

Background: 在人類探索宇宙奧秘的同時，大量的太空垃圾也被遺棄在地球軌道上。這些人造太空物體對宇航員造成了生命危害，同時也容易破壞衛星的運作。一位意大利航天局的研究人員建議發射一系列自動清掃機來清理這些太空垃圾。

After a half century of successes in space, low-Earth orbit has become a very messy place.

More than 17,000 pieces of space junk bigger than a hand's breadth are floating around up there; the largest of them weighs nearly ten tonnes.

The debris poses a growing risk to communication satellites and occasionally manned space missions.

As time goes on catastrophic collisions become more likely, which would create even more debris.

Marco Castronuovo has a simple plan to solve the problem, starting with the largest, heaviest threats.

He's proposed sending up a robotic mission that will skip between chunks of junk, affixing a little rocket to each one that will drive them out of orbit.

The debris would then burn up harmlessly in the atmosphere over an ocean.

Each orbital housekeeper could clean up five objects a year, and would be sent on a seven-year mission.

It's a slow but straightforward solution to a problem that could otherwise leave low-Earth orbit completely unusable.