Levels of space junk are close to a tipping point, the European Space Agency (ESA)'s top safety official has warned.
Earth's orbit is polluted by more than 34,000 man-made objects and there is no international regulation to force operators to retrieve their debris or abandoned devices.
Destroying objects in orbit is not an option as it would simply generate smaller debris.
The scale of the problem was illustrated in September when an ESA satellite had to dodge a small SpaceX Internet-providing craft.
Although such near-collisions have happened before, the urgency of the issue is underlined when considering the scale of the Starlink constellation imagined by Elon Musk, comprising some 12,000 satellites.
The animation above shows the distribution of space debris of different sizes based on a statistical model.
The ESA has recently commissioned the first space debris removal mission to Swiss startup, ClearSpace. The mission ClearSpace-1 is planned to operate in 2025 and will "hug" the unwanted VESPA satellite using four robotic arms and put it back in the atmosphere where it will disintegrate.
“Imagine how dangerous sailing the high seas would be if all the ships ever lost in history were still drifting on top of the water,” said Jan Wörner, ESA director-general in a briefing about the mission. “That is the current situation in orbit, and it cannot be allowed to continue.”
As for climate change, if nothing is done “we are heading for disaster” says Holger Krag, from the European Space Agency’s Space Safety department, in charge of the space debris. Euronews had the opportunity to discuss the issue during the recent European Space Week in Helsinki.
"Space sustainability" is one of the key issues for the space community and had a dedicated session during the European Space Week plenary. The arrival of new players able to put into orbit dozens of tiny satellites -the size of a shoebox- doesn't help reducing space waste.
Space rule number one: there are no rules
People unfamiliar with space regulations might imagine that there's a sort of air traffic control up there. In fact, there is none. "ESA is not a regulator," says Krag. Nor is NASA.
"The space regulation from a legal point of view is that you have freedom. Every country has freedom to access space, almost unlimited freedom, and the actors in a country have the same freedom," he said.
"In other words, freedom only stops when you start influencing the freedom of another. So you cannot put up just a law or a rule. That’s why I believe having an international regime like the one of air traffic won’t happen anytime soon," says Krag.
He believes the solution will come from pragmatism and responsibility from the operators. "Today you can broadcast your position, your maneuver plans," he says. "This is a piece we can deliver already today."
He is optimistic of progress, saying that "signs are good."
If you fear a crash, send an email
There is also no international platform to organize or monitor space traffic. If your satellite might collide with another, you send an email to the operator.
But there is not even a central database of email addresses, nor is there any obligation to answer, or any protocol for who has to do what.
An estimated 2,000 active 3,000 inactive satellites are orbiting over our heads, along with rockets and other parts totalling an incredible 34,000 objects.
Currently, the main control room for potential space collisions is the U.S. Air Force's Space Surveillance Network. "They are very pragmatic in sharing their data. It's an extremely meaningful source for anyone operating spacecraft, you couldn't do without them" explains Krag.
But it's imperfect. "It's a military system so it didn't need that much accuracy," he says. It was created to protect the United States, not to track tiny objects flying at 40,000 km/h. The alert system is not very reliable, resulting in frequent false alarms that cost time, money and man-hours.
"Today, ESA has a fleet of 20 spacecraft to operate," Krag says. "For each one of these 20 spacecraft, we are getting several hundreds of collision alerts in a day. That keeps us quite busy. Most of them are false alerts because the data lacks accuracy. We are acting based on probability."
The solution lies in improving accuracy through surveillance, he believes.
"Debris flies at 25,000 km/h so the solutions needed are different from regular air traffic operations," he says. "We need to coordinate, and it needs to be automated. We can't wait for the UN to put in place a central traffic management system, there needs to be a pragmatic solution among the operations already up there."
Bring the rubbish home
One of the solutions is to devise ways of bringing existing debris 'home'.
It's not an easy task. Imagine a tiny object, not emitting any light or signal, flying at 25,000 km/h on a random orbit. At such a speed, the tiniest piece of junk can cause devastating damage. The solution would also have to be cost-effective as it would need to operate several thousand times.
It is not possible to stop objects using a "wall" because of space dynamics in which debris would simply bounce in the opposite direction. That is why the ESA has chosen the "robotic hug" ClearSpace-1 method.
"It's like tentacles that embrace the object because you can capture the object before you touch it. Dynamics in space are very interesting because if you touch the object on one side it will immediately drift away, so you can embrace it before you touch it then grab it".
"Let's not forget this is an extremely difficult exercise. It's already difficult to dock with a cooperative object like the International Space Station. Now we want to do that with an object which we don't even know precisely which status has, is it flying still, is it tumbling... it doesn't send any signal, we have to determine its location from the ground, then later from space, we have to meet it, capture, then we have to move that down to get it out of space. That hasn't been done before".
The space community is thinking about new technologies like using the Earth's magnetic fields or plasma thrusters.
Experts say the environmental pollution caused by satellites re-entering atmosphere is almost negligible. Nevertheless, the ESA is working on more efficient and green fuels, better waste management and a reduction in toxic materials on spacecraft.
Ensure future devices can come back
In addition to debris removal, the ESA says every operator should make sure they can bring their devices back to Earth.
The best solution is to keep some fuel for the maneuver, but operators often use the satellite as long as possible, leaving them stranded without enough fuel to do the re-entry.
Krag says this is not necessarily a case of bad faith, as it's very difficult to bring an object down — only 50% of missions manage it.
Among the new private space actors, Krag says some are trying to be "clean" and are asking the traditional players on how to avoid adding debris to space, some are less worried about it.
Registering a shuttle to the United Nations is advised in the international guidelines but it's on a voluntary basis. Space operators have to comply only with the legislation in each country.
"A good enhancement would be a monitoring mission that comes to the operations center to do a technical inspection, as you would do with your car once a year," Krag says. "The other thing we need is technology, and there the ESA can help. For example, an independent engine, and an independent communications system for satellites allowing to use them after their end of life."
Krag warns that the feared Kessler syndrome — a cascading effect of collisions, and feedback collisions, is already happening right now. Even if space exploration ended today, he says, "the number of objects would keep growing due to the collisions".
"We should at least constraint this effect. It is like for climate change, where warming beyond 2ºC would create cascading effects. If we continue the way we do now, it will be a disaster. The new players must behave much better than we did in the past."