Current DateSeptember 19, 2021

Space Debris: explosion of defunct satellites exacerbating the problem

There are currently countless pieces of space junk flying around the Earth. And the amount of waste in orbit around our planet is expected to increase exponentially as more and satellites are being launched every year. It’s a worrisome issue. Because if we’re not careful, some parts of space will become full of fast-moving junk, effectively rendering these areas unusable.

Indeed, since the beginning of the space age in 1957, numerous rockets, spacecraft and instruments have been launched into space. What should happen to them after they have reached the end of their lives? No one really thought about that. However, this lack of planning means that the planet is currently enveloped by a curtain of discarded satellites and other space debris. In other words, hundreds of thousands of dangerous shards are now flying around the Earth with no plan in place to remedy to the situation. The problem is even expected to exacerbate as these satellite remnants continue to collide with each other or even explode.

Furthermore, researchers from the European Space Agency have come to a striking conclusion in their annual report on the current state of the space waste problem. According to them, explosions from discarded satellites are the main cause of all the space debris that is floating around. “Think of explosions caused by the remaining energy – fuel and batteries – on board spacecraft and rockets,” explains researcher Holger Krag. “Although measures have been taken to prevent this for years, we do not see such events as common.”

And that’s pretty worrisome. Because the more space debris there are, the more collisions we can expect in the future, which will then lead to more space debris; a phenomenon known as Kessler syndrome. The concentration of space debris around the Earth will become so large that collisions between objects will trigger a chain reaction, with each collision producing space debris that increases the likelihood of further collisions. Eventually, some parts of the space will become full of fast-moving space debris, effectively rendering these areas unusable. Although this scenario must be avoided, some scientists claim that we are already at an early stage of the so-called Kessler syndrome.

“Given the constant increase in space debris, we need to develop and deliver technologies to make space safe again,” Krag says. “At the same time, regulators need to better monitor the status of space systems and global compliance with the reduction of debris under their jurisdiction.” In the meantime, some international guidelines and standards already exist. For example, rockets and spacecraft must conform to a particular design, so as to minimize the amount of fragments released during launch or the mission itself due to the harsh conditions in space. Also, stored energy must be released steadily after a vessel or instrument has reached the end of its life, thus preventing explosions. In addition, defunct instruments must be moved to a so-called ‘graveyard orbit’ so that they do not come into contact with working satellites. And finally, collisions should be avoided by carefully choosing the correct orbit around the earth and performing timely avoidance maneuvers.

Although not all satellites currently in orbit comply with these guidelines, more and more space agencies and private companies are trying to follow the rules. This is particularly important for the satellites that are in busy orbits around the Earth. In geostationary orbit, there is clear commercial interest for operators to keep the environment free of defunct satellites and debris. And that is also reflected in the figures. For example, it appears that between 85 and 100% of operators with instruments that had come to the end of their lives in the last decade tried to comply with the measures. 60 to 90 percent did so successfully.

“We have seen fundamental changes in the way we use space,” says researcher Tim Florer. “In order to continue to benefit from the science, technology and data that space operations bring, it is critical that we better comply with existing guidelines to reduce space debris in the design of missions. It cannot be stressed enough: this is essential for the sustainable use of space.”

In the meantime, ESA itself is also rolling up its sleeves to clean up space debris. In 2025, the ClearSpace-1 currently commissioned by ESA will clean up a rocket staircase dumped around the earth. This 100 kilo object is located at an altitude between 660 and 800 kilometers around the Earth. With its simple shape and sturdy construction, Vespa is ideally suited as the first target for the Clear-Space-1 mission. Then it’s bigger and more challenging debris. In the end, the ClearSpace-1 even has to pluck multiple objects from the sky at the same time.

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