B2 First - Reading Gapped Text Exercise

Space Junk

There is an ever increasing number of objects in low Earth orbit. A camera, a glove, a hand tool, even a toothbrush: they are all up there, above the clouds, going around and around the Earth. There are also thousands of pieces of metal and plastic. Some of them are only about the size of a fingernail. (1)  Scientists consider all these objects to be "space junk," and they are a problem.

Since people first launched rockets into space in the nineteen-fifties, we have been leaving behind all sorts of things. Some of them, like the camera, were lost by astronauts while they did work outside their spacecraft. (2) 

Some things we send into space fall back toward Earth and burn up in the atmosphere. But larger pieces sometimes survive the extreme heat and hit the ground or the ocean at great speeds. So there is always concern that something may fall from the sky and do some harm.

But space junk falling on housetops is not the biggest worry. Scientists are concerned about the "Kessler" syndrome. It is named for the American scientist who first thought of the idea in 1978. Imagine what happens when an empty rocket strikes another while orbiting the earth. (3)  They then hit other things. The pieces get smaller and smaller until they form a cloud of junk that blocks the path of future space vehicles.

So what can be done to clean up the space around our planet? Marco Castronuovo, an Italian Space Agency researcher, has an idea. In the publication "Acta Astronautica," he writes about launching a satellite into space that would get very close to some of the larger pieces of space junk. The satellite would connect a small rocket to the useless object. When the rocket explodes, it pushes the junk into a lower and slower orbit, nearer the Earth. (4) 

Mr. Castronuovo has proposed using a number of small satellites with robotic arms. One arm would catch the space junk, and another arm would connect the rocket. He imagines that each satellite would jump from one large piece of junk to another. He thinks this method could destroy about ten large objects each year.

Scientists have been concerned about space junk for many years. (5)  Mr. Castronuovo says his system could be put in place for a much more reasonable amount of money.

source: voanews