London —

Germany and the United Kingdom have warned of the growing threat posed by Russian and Chinese space satellites, which have been regularly spotted spying on satellites used by Western powers.

The countries have in recent weeks highlighted frequent instances of Russia stalking, jamming and interfering with their satellites in space.

“Russia’s actions, especially in space, pose a fundamental threat to us all. A threat we can no longer ignore,” German Defense Minister Boris Pistorius told a Berlin conference of space industry leaders in September.

Targeting communications satellites can impact things like satellite imagery, telecoms and broadband satellite internet access. Disrupting navigation and positioning systems can impact military operations as well as civil aviation, according to the global think tank RAND.

The warnings come in the wake of Russia’s full-scale invasion of Ukraine, now well into its third year. Ukrainian officials say Moscow has increased its level of cooperation with China, with Beijing conducting satellite reconnaissance of Ukrainian territory on its behalf.

Here is what officials and experts say about the satellite threats in space.

Pistorius noted that two Russian reconnaissance satellites were recently spotted tracking two IntelSat satellites, which are used by the German Armed Forces and its allies. IntelSat is a commercial satellite services provider whose fleet is used by governments and companies in the US and Europe.

“Russia and China have rapidly expanded their space warfare capabilities in recent years: They can jam, blind, manipulate, or kinetically destroy satellites,” Pistorius added, announcing a multi-billion-dollar boost in funding for German space programs.

The head of the UK Space Command also sounded the alarm, saying that Russian satellites are stalking British assets in space, as well as jamming them on a “weekly” basis.

“They’ve got payloads on board that can see our satellites and are trying to collect information from them,” Major General Paul Tedman told the BBC last month. Jamming is conducted using ground-based infrastructure. Russia has spent years developing electronic warfare capabilities amid the war in Ukraine.

Separately, NATO Secretary General Mark Rutte once again warned this year of Russia’s plans to develop nuclear weapons in space to disable and destroy satellites.

Russian President Vladimir Putin has publicly said Moscow has no intention of deploying nuclear weapons in space. But Russia also vetoed a UN Security Council resolution that called for member states to not develop space-based nuclear weapons in 2024. China abstained from voting.

How does satellite ‘spying’ work and how is it detected?

In general, it’s relatively simple for space forces to detect and locate foreign satellites, but it’s difficult to determine their exact capabilities and intentions.

Authorities make assumptions about the intent of Russian satellites based on where the satellite is in space, what else it’s near and historical patterns of what similar satellites have done, according to expert Clayton Swope, the deputy director of the Aerospace Security Project at the Center for Strategic and International Studies (CSIS) in Washington, DC.

For example, if a Russian satellite lingers for a long period of time near a European communications satellite, authorities can infer that it’s there to spy.

Experts believe the Russian satellites that got close to the two IntelSat satellites used in part by Germany were there to intercept signals.

Meanwhile, in lower orbits, Russian satellites have previously tested “things that look like weapons and fired projectiles,” Swope told CNN. Authorities can identify satellites that look similar to those equipped with projectiles to determine that they are a physical threat to other countries’ assets.

“The Russians have a history of having those types of satellites shadowing other satellites in a way that people might think it’s a sleeper cell, waiting to strike at a moment’s notice,” Swope said.

“It’s very hard to distinguish between a threat in the sense of a weapon and the threat in the sense of intelligence collection,” he added. “Sometimes you really are guessing a lot about what the capabilities of a satellite are as well as the intentions of the operator.”

The Russian space agency has previously downplayed the danger of its weapons tests in space.

Germany and the UK are just the latest countries to sound the alarm. The United States and France first warned more than a decade ago that Russian satellites appeared to be spying and collecting information on their assets, including on commercially run satellites.

The US Department of Defense said in 2015 that a Russian military satellite had parked itself near two Intelsat satellites, prompting the US to contact Moscow about its movements, which many at the time described as “mysterious.”

Then in 2017, after France and Italy jointly launched an intelligence satellite, Russian satellites were soon getting close to it to take a look, according to Juliana Suess, a security policy researcher at the German Institute for International and Security Affairs (SWP).

“So, these kinds of behaviors are not entirely new, but I think also need to be seen in the context of Ukraine, and to be seen in the context of the airspace violations that we see Russia conducting with regard to NATO airspace,” Suess told CNN of the recent reports of satellite spying and interference. “All of these things ought to be seen in the broader context.”

China is just as much of a threat as Russia, if not more so, experts told CNN.

Although the threats from Russia are more pressing for Europe due to their proximity, “the much bigger space power is obviously China,” Suess said. Analysts have noted some sophisticated Chinese maneuvers in space aimed at getting close to other satellites, “at just incredibly high speeds and with precision that I think has really raised some eyebrows in the West.”

Some of China’s capabilities have raised international concerns, according to the SWP analyst. For example, China has tested a satellite with a robotic arm that can shift other satellites into a different orbit.

China also has “a lot more money to conduct themselves in space,” Suess said. “We’re not going to see much more space growth out of Russia at the moment. Their resources are far too stretched for that.”

Beijing’s activities in space are very active and their objectives are more opaque, according to Swope, the CSIS analyst.

“We don’t always know what they’re doing, and they’re doing a lot of different things that leave a lot of people scratching their heads,” Swope added.

Germany said it will budget up to €35 billion ($40.2 billion) over the next five years for space projects.

“It is a big number, for sure. I think it also reflects that there’s a sort of political will to now catch up and, you know, really get things going,” Suess said. But she also stressed that the space race is an ongoing process, with no finish line in sight. “Europe as a whole has a lot to catch up on. Germany certainly has a lot to catch up on.”

A spokesperson for the German Ministry of Defense told CNN that its procurement measures relating to space will amount to around €1.9 billion ($2.2 billion) in 2025, “but will grow significantly in the coming years.”

The UK government also announced a commitment to increase defense spending this year and a strategic review of British capabilities outlined that “greater attention must be given to the space and cyber and electromagnetic domains.” The UK announced in October that it is testing sensors to detect laser threats in space as part of measures to protect British satellites.

But an analysis from the London-based think tank Chatham House argued that even greater near-term investment is needed, and that the strategic review failed to recognize how urgent the threats in space truly are, putting the country at risk of falling behind.

Meanwhile, France has “been very vocal about the need to have what they refer to as ‘bodyguard satellites,’ so, satellites whose job it is to protect other satellites,” Swope said. What those satellites will look like is an open question, he added, with development ongoing.

The US still has a historic advantage in space after investing much more in recent years, analysts said. But European allies may benefit from that through cooperation under the North Atlantic Treaty Organization (NATO) and other alliances.

NATO declared in 2019 that space is an “operational domain” for the transatlantic alliance and years later announced that Article 5 would apply in space. Article 5 is the principle that an attack on one NATO member is an attack on all members. Analysts at RAND have argued, though, that NATO needs to “throttle up” on its space enterprise or risk falling short at a critical time.

While falling behind is a real concern, particularly compared to China’s advances, there is also evidence that the Russia has not integrated its satellite systems into its military infrastructure as well as many other space powers.

Suess cited an example of a Russian fighter jet downed in Ukraine that was found with a built-in Russian navigation system but also a commercial GPS taped to the dashboard. Analysts have also seen evidence that Russia is procuring commercial satellite imagery from the private market – an indication that its own capabilities are not up to scratch.

“We have seen from anecdotal evidence in Ukraine that Russia does not have some sort of level of confidence that one would typically expect in their own systems,” Suess added.