What weighs 2 300 tons, travels at an average speed of 27 000 km/h, and is becoming a growing concern for the international community? Answer: the space debris in the so called Low Earth Orbits. Dead satellites, old rocket boosters, pieces of destroyed spacecrafts and the like is what constitutes this massive scrap yard that is constantly revolving around Earth. While space may appear infinite, it still has its limits.
Since the beginning of the space age in October 1957 when the Soviet Union launched the Sputnik 1, we humans have sent over 6000 spacecrafts into outer space. Out of these spacecrafts, a big chunk has been satellites. There are as of now over 1 000 operating satellites in orbit around the earth, and around half of these are flying at an altitude of between 160 and 2 000 kilometers above sea level. Orbits in this interval are called low Earth orbits (LEO), and it is mainly in these orbits where the issue of space debris comes into play.
When a satellite is worn-out, there are two alternatives. Either it has been programmed to de-orbit back into the atmosphere to incinerate, or it stays in orbit until it de-orbits by itself, which can take a long time. In the past, the latter has been quite common, which together with some daring endeavours has resulted in a big amount of junk now circling around in LEO.
So why is this a problem? Well, although a majority of the junk are pieces of relatively small size – most of them are not bigger than one centimeter in diameter – at tens of thousands of kilometres per hour, even the tiniest fragments can cause notable damage to the spacecraft still in use. Also, and most importantly; the number of bigger scrap pieces is increasing at an exponential pace. This development is caused by ever more densely populated orbits which means more collisions between the objects in them, creating even more debris. If this growth continues, which it will if we do not actively start removing debris, space missions into any LEO could in the future become practically impossible due to the elevated risk of collision, in turn leading to severe implications for weather forecasting, telecommunications, scientific research, the global positioning system (GPS) and many military applications (especially for the US). We have become so reliant on the low Earth orbits, both on a geo-political scale and in our day-to-day lives that we just cannot seem to afford to lose this unique environment.
There are things being done to attend this problem. For instance, in 2009, the first ever international conference on orbital debris removal was held in Virginia, US, to discuss possible technical solutions for the current situation. However, because of the nature of the issue, there is still a lot standing in the way of a solution.
One part of the complications is the purely technical aspect. A cost-efficient, secure way of actually removing the debris from its orbits is yet to be found. Robotic arms that would grab the debris and bring it back into the atmosphere, lasers which would disintegrate the debris into negligible size, electromagnetic fields that would drag the debris close enough to Earth to de-orbit; the suggestions have been as creative as they have been numerous, and what particular solution or combination of solutions that will actually be used remains to be seen. It is also to be decided how the costs of any of these operations would be divided. One could argue that those who put the junk there – mainly USA, Russia and China – should be the ones who pay for its removal. On the other hand, since every nation would benefit from a clean space environment, this could make the big space nations reluctant to pay for it by themselves, seeing that it allows for a lot for “free-riding” by the smaller, emerging space nations.
Another complicating matter is that anything that could be used to remove debris also could be used to remove functioning satellites. The fear of other nations “accidentally” disrupting one’s own satellite system feeds suspicion among countries that are already not on the best terms with each other. Recently, Japan announced they would deploy an electromagnetic tether to test its potential to remove space debris. This action is speculated to have increased the tension between the nation and its neighbour China, a relation which was already shaky due to the two nations’ territorial dispute in the East China Sea. There are also legal issues involved in space debris removal, since any part of any spacecraft, according to international space law, remains the property of whoever launched it. To remove a piece of junk from orbit that is not yours, you would first have to ask the owner of it for permission. All this could be a very time consuming process, time which we might not have.
Since the issue of space debris is a global one, it surely must be jointly tackled by the entire international community. To solve the political problems involved, one alternative could be to launch all large scale debris-removal missions from a neutral state, to increase transparency and minimise suspicion between rivalling nations. Switzerland has been suggested as a possible candidate for this.
New technological breakthroughs tend to give rise to new problems, and perhaps it was only a matter of time before space activity got complicated. Just like we have been polluting Earth during the industrial age, we have been polluting the low Earth orbits during the space age. The time to do something about this might be now if we wish to keep enjoying the services provided by satellites. To reach any solution, however, less hostility and more co-operation among nations will be needed.