What Will It Take To Reach Zero Space Debris?

The space debris problem won’t solve itself. We’ve been kicking the can down the road for years as we continue launching more rockets and payloads into space. In the last couple of years, organizations—especially the European Space Association—have begun to address the problem more seriously.

Now they’re asking this question: What will it take to reach zero space debris?

At first glance, it may seem unreal, maybe naive. There are billions of pieces of space junk orbiting Earth, and more than 25,000 of those pieces are larger than 10 cm. Though small, these pieces are travelling fast and can cause significant damage when impacting satellites or space stations. What will it take to get rid of all this debris?

The ESA has released the Zero Debris Technical Booklet to elucidate the challenges to a zero-debris future and propose solutions to get there. The Booklet’s development follows the signing of the Zero Debris Charter by members of the Zero-Debris community.

“Despite several initiatives for space debris mitigation in recent years and modest improvements in public awareness, there is a general consensus that more ambitious actions are urgently needed from all space stakeholders to prevent, mitigate, and remediate debris,” the report states. The report points out that the Guidelines for the Long-term Sustainability of Outer Space Activities of the United Nations Committee on the Peaceful Uses of Outer Space outlines how access to space is hindered by debris.

The booklet defines zero debris targets and presents “technical needs, solutions and key enablers” that can help organizations achieve them.

The obvious first step is to cease creating more debris.

It begins with avoiding the unintentional release of debris. Exposure to the space environment can degrade materials during missions and beyond their end date, and unintentional impacts can also release debris. The Booklet promotes the “Development of multi-layer insulation and coating technologies preventing long-term degradation of materials” and similar developments for materials that can resist impacts. Improved monitoring, simulations, and testing can help us get there.

The Booklet also points out the need for different propulsion technologies. Some propulsion technologies release enormous quantities of small particles. The Booklet promotes the development of alternate propulsion systems based on things like electromagnetic tethers, momentum-transfer tethers, and drag or solar radiation pressure augmentation devices.

The Booklet also points out how improved Space Traffic surveillance and Coordination (STC) can help solve the problem. “Improved STC will help prevent collisions and reduce the occurrence of unnecessary collision avoidance manoeuvres,” the Booklet states.

That will require a technological solution, but different space agencies will also have to share information, which some will be more reluctant to do than others. The Technical Booklet explains that standardized guidelines will need to be developed and adopted for this to happen.

For existing debris, removal is the only solution. “For space objects which fail to de-orbit themselves for whatever reason, external means can be used to remove these objects from orbit,” the Booklet states.

That begins with assessing defunct satellites to determine the best way to de-orbit them. Are they at risk of breaking up due to de-orbiting methods? Once assessed, we need to develop reliable and configurable methods to remove them. That means a technological approach will be needed, as will communication between different space-faring nations.

The Booklet states that this will require the “Development of interoperable interfaces and requirements that facilitate removal for different types and sizes of objects (e.g. large/Small Spacecraft, launcher stages and elements, constellation spacecraft), adapted for different orbital regions (e.g. LEO, MEO, GEO), for different Disposal strategies (e.g. controlled, uncontrolled re-entry, orbital transfer to graveyard orbit), and with easy adoption in mind,” the Booklet explains.

De-orbiting systems could be as simple as deployable solar sails like the experimental Canadian Advanced Nanospace eXperiment-7 (CanX-7.) It was launched in 2016 and achieved a decay rate of 20/km per year.

While the CanX-7 and other similar systems are passive, there are also designs for Active Debris Removal (ADR).

One ADR system is Clearspace-1. It will demonstrate technologies for rendezvousing, capturing, and de-orbiting an end-of-life satellite called PROBA-1. After capture, both Clearspace-1 and PROBA-1 will plummet into Earth’s atmosphere and be destroyed.

Predicting and avoiding the risk of collisions between satellites and other objects in space is also part of the Booklet. “The increasing number of debris and the risk associated with collisions in orbit lead to an
ever-increasing need for operators to carry out collision avoidance manoeuvres,” the Booklet states. This can be partially addressed during the design phase but inevitably requires coordination.

Again, the Booklet calls for more cooperation between agencies. The effort needs a standardized set of guidelines for collision assessments and “methods to integrate collision risk assessments from multiple providers.”

When it comes to technology, collision avoidance and prediction will also benefit from the development of machine-learning algorithms, the development and uptake of optical and radio tracking aids, and a longer list of additional developments.

The Technical Booklet summarizes our problem: Space Debris requires standardized methods to assess hazards, avoid hazards, and remove hazards. While the technology needed to address the space debris problem hasn’t been thoroughly developed yet, there’s little doubt that it will be. However, the needed technologies may not be the biggest obstacle to solving the space debris problem. The critical part is cooperation.

Without cooperation, the problem will never be fully solved. However, cooperation can be in short supply. Our species is at least partly defined by our internecine squabbling and the tragedy of the commons. Different nations have different ideologies, politics, and leadership. Can we imagine Russia under Putin taking part in a cooperative effort to reduce space debris? How about China? North Korea? Iran?

What’s worse, some nations are actively creating more debris. In 2007, China conducted an anti-satellite missile test that destroyed a defunct satellite and created a massive amount of debris. In 2017, Russia did the same. India conducted a similar test in 2019, though they claim that it was at such a low altitude that the debris would quickly burn up in Earth’s atmosphere. However, the US Strategic Command said the debris remained in space longer than India claimed.

It doesn’t seem likely that the planet’s nations and space agencies will be cooperating any time soon, and even the once-reliable United States may eschew increased cooperation under its new leadership. Who knows?

But just as with climate change and a host of other problems, we can only solve the space debris problem through cooperation.

The ESA deserves credit for outlining the technical challenges and solutions to the problem. Though daunting, that may turn out to be the easy part.

It’s our politics that hamper the effort.

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