Space junk

Leon has a new hobby — whenever he goes jogging in the neighbourhood, he picks up rubbish he finds along the way. People leave behind so much litter! And it’s not just in Leon’s neighbourhood. Rubbish seems to follow people wherever they go — the deepest ocean, the highest mountains, and — even space! - What? Rubbish in space?

How is that possible? Since the beginning of space exploration in the 1950s, people have launched countless devices into the earth’s orbit. For a long time the main focus was to send things out, and no one really bothered with how to return them, once they were no longer needed. What happened to all these objects? Many years after they stopped functioning, the majority are still circling the earth at an altitude between 200 and 35,000 km.

Satellites and rocket parts that disattached during launch; loose nuts and bolts that came off various devices; and items astronauts lost on their space missions, such as a tool bag, or spatula. All these objects create an ever growing cloud of space debris or space junk. So what?? Space is huge! How much harm can a little spatula do anyway?

Well, one issue is the amount of space debris. There are hundreds of millions of objects orbiting the earth, in all shapes and sizes. And in the middle of all that space junk, there are still thousands of functioning satellites and other devices. The space around our planet is very crowded, which makes it difficult for scientists to study space from Earth. With so many objects moving constantly, there is also a high probability that some crash into each other.

As all these pieces are moving at enormous speeds of thousands of kilometres per hour, the effects of such collisions can be very dangerous. One such spectacular collision occurred in February 2009. A retired Russian satellite and a US commercial communication satellite crashed into one another at a speed of 42,000 kilometres per hour. Both satellites were destroyed, creating thousands of pieces of new debris. To avoid such collisions, most space junk has to be tracked constantly.

Very small objects pose an even greater risk than large ones, because they are nearly impossible to detect or track. A tiny piece of metal, this fast, can easily make a hole in a spacecraft hull, crack a telescope mirror, or break off a section of satellite. Which means the device can stop working, which might require costly repairs, causing problems for us on Earth. Each such collision occurring in space creates new debris, increasing the costs and risks of space exploration. So maybe we should stop sending stuff into space?

Or start a space cleaning program? Well, it’s very unlikely that people will give up launching satellites and space missions. It’s become too important for scientific research, technological development, for everyday life. Sooner or later though, all pieces of debris exit their orbit. Pulled by the earth's gravitational force, they will eventually burn up in the atmosphere.

This, however, takes many years. We need better, more effective solutions. There are several ideas: space nets that would capture the debris, giant magnets that would pull it down, and an electronic whip that would knock the debris out of the orbit. But all these are costly and difficult to carry out. The best thing would be to make sure that all new objects sent out to space are designed in such a way that prevents them from becoming space junk in the first place.