So many satellites. Can we clean up space?

At the close of 2022, a European satellite unfurled a glimmering silver sail behind it. The purpose of this appendage was simple: to accelerate the satellite’s self-destruction by pushing it into the Earth’s atmosphere. 

Strange as it may sound at first, this was in fact just the latest in a growing wave of efforts to address a burgeoning problem facing humanity’s endeavors in space – the proliferation of debris and satellites orbiting our planet. 

We have essentially been treating space as a junkyard.

And the challenge is becoming no easier, with the United States granting Amazon authorization in early February to launch more than 3,000 satellites – not to mention a Russian missile that destroyed a defunct Soviet satellite in November 2021, creating a fresh cloud of debris that will endanger spacecraft for years, maybe decades, to come.

There is hope, as the European Space Agency’s silver sail illustrates, but the situation is complex. A plethora of countries and companies now seek to utilize the promise of space, with a range of competing and overlapping priorities. It raises the question of where responsibility lies to tackle this mess – and whether we even care.

“I think until the last few years it wasn’t people being irresponsible,” says Nic Ross, founder and CEO of Niparo, a space sustainability consultancy based in Edinburgh, Scotland. “It was people not even thinking of space as a finite resource.”

A mushrooming launch rate

In recent years, the situation above our skies has shifted dramatically. For decades, since the dawn of the Space Age in the late 1950s, the launch rate of satellites remained fairly stable, but in the past few years, it has exploded.

This exponential growth has been led not by government agencies, which long dominated the arena of space exploration and activities, but rather by commercial enterprises. Starlink, a satellite-based broadband service being rolled out by SpaceX, has already put about 3,500 satellites into orbit.

To put that in context, there are currently only 7,200 functioning satellites floating above the Earth. And Starlink has received authority to launch a further 7,500 – not to mention Amazon’s Kuiper program, which now has the green light, and OneWeb, another company that already has more than 500 satellites in orbit.

The main worry with the mushrooming population of satellites comes down to one thing: collisions.

The International Space Station has had to take evasive action more than 30 times in its 24-year history to protect astronauts on board. And falling debris has the potential to affect humans on Earth. But for now, the most frequent risks are faced by satellites.

“In ESA, when we have to perform collision avoidance maneuvers, it sometimes causes interruption of service,” says Francesca Letizia, a space debris engineer contracted to the European Space Agency. “At the moment, it’s tolerated because it only happens once in a while, but if you go to a long-term scenario where you have 10 times the number of objects, then maybe the interruption becomes more significant.”

That, of course, assumes the satellites are even able to make the maneuver. In 2009, for example, an inactive Russian satellite, Cosmos 2251, collided with an active satellite owned by the U.S.-based company Iridium. The impact produced thousands of pieces of debris, many of which will still be in orbit decades from now.

Some positive steps

Since that time, monitoring and warning systems have improved, and many modern satellites have self-propulsion capabilities, which allow them to take evasive action if another satellite flies too close. Starlink satellites, for example, have already had to undertake more than 26,000 such maneuvers. The concern is that as particular orbits become ever more crowded, the task of avoiding every conceivable collision will become more difficult. 

And it’s not just other satellites that have to be taken into account. It’s also the hundreds of thousands of pieces of debris hurtling through the same orbits. Some of these originate from accidents – perhaps collisions, or explosions caused by unspent fuel. But some are created intentionally.

“The biggest problem we have right now is countries testing their own missiles against their own satellites,” says Krystal Azelton, director of space applications programs at Secure World Foundation, a U.S.-based organization that promotes cooperative solutions for space sustainability. 

“People on Earth receive immense value from space,” continues Ms Azelton. “It is fragile, it’s not infinite, and it needs to be managed in a way that is sustainable.”

And this cuts to the core of why we should care: The number of industries, down here on Earth, that are reliant on space is only growing. So many of our day-to-day activities now depend upon satellites, not least all the mapping and navigation on our phones. Yet a recent report indicates that the vast majority of us deeply underestimate the role that space plays in supporting our way of life.

Magnets and harpoons

Efforts are afoot to address the threats. On the one hand, for example, there are companies seeking to remove objects in orbit that are no longer functional – a process known as active debris removal. Concepts include the space equivalent of a net, a magnet, or a harpoon.

One of the most recent trials involved small-scale plasma thrusters attached to a CubeSat (miniature satellite), enabling it to power itself into Earth’s atmosphere and burn up once its mission is over. CubeSats, which can be as small as a tissue box, are responsible for a big chunk of the ballooning satellite population, so finding ways to facilitate their de-orbit could produce outsize returns in efforts to keep space a little cleaner.

Another approach is to minimize the creation of further debris, largely by fostering international agreement on what the norms of behavior should be. The Inter-Agency Space Debris Coordination Committee, for example, has set down the guideline that all satellites in low Earth orbit should be removed from that orbit within 25 years of end of mission – a number that the U.S. recently unilaterally reduced to five years. 

Of course, much of this hinges on whether nations abide by the frameworks, and how they value responsibility in their national policies. But many analysts agree that while there are gaps and deficiencies, it is in the interests of all parties, both public and private, to keep space usable; self-interest, in other words, generally encourages compliance.

Yet some space experts argue the solutions run deeper than just addressing the physical congestion in certain orbits.

“I think we can solve this”

“When I look at the definition of space sustainability, I question whether or not the guidelines we have actually fit within the framework that space is for everybody,” says Hugh Lewis, a professor of astronautics at the University of Southampton in England. “For me, it’s shifted from a typical engineering problem to something that’s centered around ethics, morals, and responsibility.”

Dr. Lewis, who represents the U.K. Space Agency at the interagency committee, notes that all of humanity has an interest in space, yet a relatively small number of nations have held sway there. Newcomer nations must by definition adapt to frameworks set by established heavyweights, and fit in where they can. 

That’s the case even though, as Spock from “Star Trek” put it, “the needs of the many outweigh the needs of the few.”

Another problem highlighted by both Dr. Lewis and Dr. Ross of Niparo is the way satellites are so often de-orbited by simply directing them into Earth’s atmosphere and letting the colossal pressures and temperatures involved essentially vaporize the spacecraft. This tosses aside the notion of a circular economy that reuses materials, and raises concerns about the effects on the atmosphere when those materials are deposited in its upper reaches.

“I think I’ve been quite pessimistic, but ... collectively, as humanity, I think we can solve this, just as I hope for with things like climate change,” says Dr. Lewis.  

“I think we’re very good at giving ourselves the worst case to dig out of, and that’s certainly where we’ll end up with space debris as well, but I have hope we can dig ourselves out and find solutions.”