Hard and expensive to clean up space debris

Soon, 62 years have passed since the first satellite, Soviet Sputnik, began the space age. After a couple of months Sputnik was scraped, sunk into the atmosphere and burned up.

Today, there are about 5,000 satellites around the earth, according to the UN Register. About 2,000 of these are active, according to statistics from the American organization Union of Concerned Scientists.

Satellites can stop working if the sun gets an outbreak and sends large amounts of radiation towards us, but the increasing problem is those that break because they collide with scrap. At the crash, a metal structure transforms into splitter, and each splitter can then cause damage.

In some cases, clouds of splits have been blamed, as when a number of years ago China shot its own old weather satellite with a missile to show that it could do so.

In 20 years, European space agency ESA estimates, every fifth satellite could be damaged or destroyed by scrap. "The scrap is replenished faster than it is cleared," says one expert. Something must be done.

Johan Köhler is the Swedish Space Agency's expert on space scrap and he believes that space cleaning where you take care of the big pieces is the right way to go:

- This is the kind of technology you develop and intend to use. To acquire the ability to go near a satellite, grab it and send it down into the atmosphere where it burns up. What determines whether it gets rid of is the political will and the financial opportunities, he notes.

It is practically impossible to push scrap out into space instead. Then additional fuel is required that you would rather not need to carry on board.

Since a small piece of scrap can punch holes in the International Space Station's hull and thus at worst kill the crew, new protective materials are tested. But as soon as the astronauts work outside the hull on the space walk, they are unprotected again. US NASA is experimenting with robots to do such jobs. But they can also be destroyed by a hit.

So space cleaning is called for. No authority keeps track of the fact that space nations or corporations themselves cleanse themselves, if they can at all.

The practical problem is to be able to steer a cleaning satellite close to the scrap piece and get hold of it. Attempts are made with a harpoon that chops the scrap, with tentacles that wrap around it or with nets that catch it. Tests with nets have gone well but it is expensive. “About half a billion euros”, ie over SEK 5 billion, says Rüdiger Jehn at ESA.

A project to build a scrap truck is underway. At best, it will be completed by 2025.

But the trend is also going in the opposite direction as more and more people want to get satellites, for example the OneWeb project, which wants about a thousand small satellites to give the world access to the internet.

And there is a clear trend that the satellites are being built less robustly, says Johan Köhler:

- It is to be able to build many and cheaper satellites. But you are also well aware that this means that the reliability of the satellites will be poorer.

Sweden has valuable knowledge to contribute, for those who want to achieve controlled satellites, says Köhler:

- Our satellite Prism has shown that satellites can fly very close together in a controlled way.