地球轨道‘清道夫’计划

在人类探索宇宙奥秘的同时，大量的太空垃圾也被遗弃在地球轨道上。这些人造太空物体对宇航员造成了生命危害，同时也容易破坏卫星的运作。一位意大利航天局的研究人员建议发射一系列自动清扫机来清理这些太空垃圾。

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.