Los comunes en el espacio

Debris in space

Flying blind

The tragedy of the commons meets the final frontier

THE Earth’s orbit is getting crowded. The past few years have witnessed huge growth in the number of satellites. Unfortunately, wherever civilisation ventures it leaves a trail of rubbish. Of the 18,000 tracked objects travelling around the Earth that are larger than 10cm (4 inches), only about 900 are active satellites. The rest is debris—everything from fragments of paint to entire dead satellites and bits of old rockets. Smashed bits of space equipment orbit along with items dropped by astronauts, including tools and the odd glove.

That is quite enough trash, without needlessly creating vastly more of the stuff by smashing up satellites. Yet the destruction of the Chinese Fengyun-1C in an anti-satellite missile test in 2007 accounts for more than a quarter of all catalogued objects in low-Earth orbit. And the collision of an American commercial satellite and a defunct Russian military one has just added thousands more pieces of debris. For the sake of the whole planet, the space industry needs to clean up its act.

In space no one can hear you clean

Space junk is dangerous. Anything larger than a fleck of paint poses a hazard to the useful working satellites that surround the Earth, and on which the world increasingly depends for communications, broadcasting and surveillance. Space waste is not biodegradable. You cannot sweep it up. Instead, it will stay in orbit for decades, or even centuries, before it eventually falls to earth and burns up.

As the pile of rubbish grows, so does the risk of collisions. In the 1970s one NASA scientist pointed out that debris from one collision could go on to create a second, which would create still more debris and more collisions, and so on. Eventually, an entire orbit would be rendered useless for generations.

The orbits around the Earth are too valuable to let this happen. Space is a public common and humanity needs to value it. So it is time to stop so many satellites from flying blind. Although some organisations collect and analyse data on potential collisions, they are not always precise and there are gaps in their knowledge—as the recent collision has shown. The European Space Agency has said it will encourage space agencies to share more information. It will also establish standards for working more closely with America.

But that is too modest. What is needed is an international civil satellite-awareness system that would provide everyone from small governments to business with the information they need to operate safely. To create such a system cheaply, however, requires countries to pool information from their separate ground sensors. The system should lay down the rules of the road, such as who has to give way. All space-faring countries should comply with international guidelines to minimise the amount of debris created by launches. There is a strong case for a moratorium on debris-creating anti-satellite tests. And satellite-launchers should be obliged to buy insurance to cover the risk of extra costs before they venture into space, rather as car-drivers must before they take to the road. One such cost arises when a satellite has to take evasive action and thereby uses up fuel, reducing its life in orbit.

This plan need not be expensive, but it faces one big difficulty. Because orbit is open to anyone with a launch-rocket handy, some countries may be tempted to let everyone else bear the costs of precaution while they reap the benefits. The space powers can use all sorts of levers to bring such recalcitrants round, from access to technology to moral pressure. Ultimately, though, if free riders refuse, it is important that the resulting stink does not block an agreement altogether. Do not let the mess on the ground exacerbate the mess in the skies above.

En The Economist, 19 de febrero de 2009.