Space Debris

Since the first satellite was launched in 1957, humans have sent thousands of objects into orbit around the earth. Many are still working and useful, but a great many are not. Dead satellites, spent rocket parts, and countless smaller fragments from past collisions now circle the planet at tremendous speed. This growing cloud of "space debris" has become a serious problem, and experts warn that it could （ 1 ） future space activity if it is not brought under control.

The danger lies above all in speed. Objects in orbit travel many times faster than a bullet, so even a tiny fragment can cause severe damage if it strikes a working satellite or a spacecraft carrying astronauts. Worse still, every collision creates a fresh cloud of debris, each new piece capable of causing further collisions in turn. Some scientists fear that this process could （ 2 ）, filling certain valuable orbits with so much debris that they become too dangerous to use at all for many years.

Removing debris is difficult and expensive, but engineers are testing imaginative ideas such as nets, harpoons, and even lasers to capture or push down old objects so that they burn up harmlessly in the atmosphere. Equally important are new rules requiring satellites to be moved aside or brought down safely at the end of their working lives, before they can add to the problem. （ 3 ） space is shared by many countries and companies, dealing with the danger will require international cooperation just as much as clever technology.