A Russian satellite just took a very close look at an American spacecraft in low Earth orbit.

A few days ago, the snooping satellite Kosmos 2612 rendezvoused with ICEYE-X36, a commercial craft that observes our planet using synthetic aperture radar (SAR).

The close encounter, which occurred between Oct. 15 and Oct. 19, was reported by Marco Langbroek and other satellite trackers, with Langbroek calling it "a worrisome cat-and-mouse game" in orbit. The rendezvous has garnered a lot of attention in space circles, because it was non-consensual and startlingly close; at one point, the two spacecraft may have been separated by just a few meters. What did Russia hope to gain from it?

Not an isolated incident

Before tackling that question, we need to set the stage a bit. For example, it's important to note that inspections aren't unheard of in the final frontier. Russia, the United States and China have all maneuvered satellites into close proximity of other nations' hardware in recent years.

Most of this activity has taken place in geostationary orbit, which lies 22,236 miles (35,786 kilometers) above Earth. At this altitude, orbital velocity matches our planet's rotational speed, allowing spacecraft to "hover" over one patch of Earth continuously. GEO is therefore a popular destination for spy, communications and weather satellites — and for spacecraft designed to shadow and assess them.

Kosmos 2612 is operating in low Earth orbit (LEO), which is part of the reason its activities have created such a stir. Neither China nor the U.S. has conducted an uncooperative rendezvous in LEO, as far as we know. But Russia has, according to Victoria Samson, chief director of space security and stability for the nonprofit Secure World Foundation.

"They've done a few," she told Space.com. "Kosmos 2543 got within about 30 kilometers [19 miles] of USA 245 in January 2020, and then Kosmos 2558 got within about 70 kilometers [43 miles] of USA 326 in August 2022. And they've done repeated approaches to 326."

Kosmos 2612 got much closer to its target than those other inspectors did, of course. And there's another big difference: USA 245 and USA 326 are classified spy satellites managed by the U.S. National Reconnaissance Office, while ICEYE-X36 is a private Earth-observing craft.

Eyes in the sky

There are about 80 ICEYE spacecraft in LEO at the moment. They image our planet using SAR, which can peer through clouds and gather data both day and night. Some of these satellites are operated by ICEYE, a company based in Finland, while others are managed by its American subsidiary, ICEYE US. ICEYE-X36 is one of the latter.

At least some ICEYE satellites provide imagery to Ukraine, which Russia invaded in February 2022 and continues to assault with ground troops and missile and drone attacks. Indeed, ICEYE signed a contract this past January firming up this data-sharing relationship with Ukraine.

"The agreement ensures that the Ministry of Defence continues to receive a high volume of high-resolution satellite imagery through ICEYE's world-leading SAR constellation, supporting the Ukrainian Armed Forces with persistent situational awareness on tactical timelines," ICEYE representatives said in a January statement.

That likely explains Russia's interest in ICEYE satellites, which is extensive and longstanding. For example, Kosmos 2612 launched in April of this year with five other spacecraft. In May, four members of this fleet, including Kosmos 2612, conducted maneuvers to get into a co-planar orbit with ICEYE-X36. Such maneuvers use a lot of fuel and are therefore not performed lightly. (It's unclear if ICEYE-X36 is dedicated to capturing imagery of Ukraine or Russia, but Russia certainly seems to think it is.)

However, we still don't know the purpose of Kosmos 2612's close approach (which is apparently over, at least for now), Samson stressed.

There are a few possibilities. For example, Russia may want to get a better idea of ICEYE satellites' capabilities, and/or figure out what exactly they're studying on Earth below. Or maybe Kosmos 2612 was actively interfering with ICEYE-X36 in some way — messing with its sensors, perhaps, or blocking or intercepting its communications with the ground.

However, Samson leans toward another explanation.

"I think they're getting frustrated," she said of the Russians.

"They've been kind of in a stalemate, particularly for the past six months or so. And so I think it's just more a matter of demonstrating military prowess in a manner that the Ukrainians cannot respond to," she added. "The Ukrainians are just as good, perhaps even better than, the Russians on drones. But when it comes to space stuff, they're not peers, and this is just a way to remind everyone that that's the case."

As Kosmos 2612's activities show, space is becoming an increasingly competitive and contested domain. The U.S. has long held the advantage above Earth, fielding the most capable reconnaissance and communications craft, but Russia and China are challenging that dominance.

This drama is unfolding above our heads now, and it affects everyone on the planet. Samson therefore wishes that governments around the world were more forthcoming about their space activities — for example, that we learned about Kosmos 2612's shenanigans from the U.S .Space Force rather than from private companies and civilians who pore over government tracking data.

"I think it just speaks to the importance of transparency, and sharing information about these sort of things," she said. "As much as you may want to, you cannot keep the existence of satellites classified, because people can see them."

The space around Earth is turning into a junkyard. Researchers think a refundable deposit scheme could force satellite operators to clean up their act before a tipping point is reached.

For years, space sustainability experts have warned that the growing number of satellites in orbit and the quantity of dead metal left behind threatens to trigger a dangerous cascade of collisions known as the Kessler Syndrome. Predicted in the 1970s by NASA physicist Donald Kessler, this chain of orbital smashups could make the space around Earth unusable and unsafe.

The dangerous tipping might be nearer than some think. Humankind's utilization of space is at an inflection point, as companies such as SpaceX, Blue Origin and Amazon plan to launch constellations of hundreds of thousands of telecommunication satellites and orbiting data centers in the coming years.

"Low Earth orbit looks like lots of other resources that we have trashed as economic actors," Daniel Kaffine, a professor of environmental and resource economics at University of Colorado Boulder, told Space.com.

"Waiting until it gets really, really bad to start implementing any of these types of policy interventions has historically been what we have done," Kaffine added. "But maybe we can think about things we can do right now."

In a paper published last month in the journal Nature Communications, Kaffine and his collaborators propose a scheme that would require satellite operators to post a bond of $200,000 before launch, refundable with interest upon the completion of a successful deorbit. Companies that fail to remove their junk would lose the money, which could go toward a shared pool funding active debris-removal missions, the researchers said.

"You could possibly raise billions of dollars by that," said Kaffine. "We think it's a very neat policy that doesn't require international coordination."

International bodies, such as the Inter-Agency Space Debris Coordination Committee, ask satellite operators to remove their spacecraft from orbit within 25 years after the mission's end. The American Federal Communications Commission (FCC) imposes an even stricter standard — a five-year requirement for satellites in low Earth orbit. Still, a staggering 60% of satellites remain in place when their propellant runs out, the researchers say, as no consequences ensue if they fail to deorbit.

Solving the problem on the international level would be difficult, as international bodies have no powers to enforce compliance. Moreover, the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), which sets down rules for the peaceful exploration of outer space, requires the unanimous support of every member state to pass new regulations, which is nearly impossible to achieve.

"The policy we propose could be implemented on a national level, which is why we think it's interesting," Indigo Brownhall, a space sustainability researcher at University College London and the paper's lead author, told Space.com. "Any country in Europe can request satellites registered with them to follow this bond policy."

To put it simply, no satellite registered in a given country gets to space before putting the money into the kitty. The researchers acknowledge that it might be hard to persuade major players historically averse to regulations, such as the U.S., to roll out such a scheme. But they say a more environmentally conscious block, like the European Union (EU), could enforce compliance by limiting market access to those who observe their rules.

"The consumer market in Europe is massive, like 300 to 400 million people," Brownhall said. "And the EU can request anyone who wants to sell space data or any products in the EU to follow their rules. They did this with GDPR [General Data Protection Regulation]. And you can imagine that somebody like Starlink [SpaceX's satellite-internet subsidiary] surely wants to sell Starlink terminals to Europeans."

The authors estimate that, even if the scheme only covered 20% of global satellite launches, it would reduce the number of derelict satellites careening around the planet by 18%.

Currently, more than 57,000 pieces of space debris larger than 4 inches (10 centimeters) hurtle around Earth completely out of control, according to estimates by the European Space Agency. That's double the figure from less than 10 years ago. Most of these fragments were generated by explosions and orbital collisions that shattered satellites and used rocket stages into clouds of dangerous debris.

"Leaving big satellites that no longer work up there is like a ticking time bomb," Brownhall said. "Active satellites can move out of the way, but when two derelict satellites are going to hit each other, there is nothing you can do but watch it."

Kaffine said the policy could be modelled on U.S. oil operators' bond scheme, in place since the 1960s, which ensures that oil giants plug used oil wells after ceasing extraction.

"If the oil operators clean up after completing the oil production job, they get the money back," said Kaffine. "If they don't, the money goes into a fund, which the government then uses to clean up orphan wells. It's quite an analogous situation to what we see in space."

In the meantime, evidence of the worsening orbital situation is coming thick and fast. Space situational awareness companies such as U.S.-based LeoLabs, which use networks of ground-based radars and telescopes to monitor traffic in space, report increasing numbers of disintegration events — incidents involving either an explosion or a collision between old satellites, fragments and rocket bodies. In the past six months, LeoLabs has reported at least four fragmentation events in space, which together created hundreds of new pieces of space debris.