China calls them scavengers, Russia calls them inspectors and the U.S. calls them threats.

The race is on to clean up the space junk orbiting above our heads. But fears are these trash collectors are really killer “gremlins”.

Touted as space-junk clean-up drones, they also have the potential to grab vital GPS, communications and surveillance satellites — and send them hurtling towards the ground.

And strange things are already happening in orbit.

Analysts are asking: is it space junk, or sabotage?

Several critical geostationary orbit satellites have been reporting anomalies. Most recently, Intelsat 29e — which provided communication and navigation services to the Caribbean and North Atlantic — “experienced damage that caused a leak of the propellant on board the satellite”.

Nobody is yet suggesting sabotage. Space junk remains the number one suspect.

But as the satellite was only three-years-old, and joins five other major satellite malfunctions in the past two years, the incident has started analysts talking.

Is space junk already getting out of control? Or is something more sinister at play?

According to the Massachusetts Institute of Technology (MIT), attacks against satellites may have already happened.

COLLISION COURSE

Last year, fears Moscow was developing a secret satellite saboteur were renewed when what was initially believed to be a piece of space junk left over from a rocket launch began to behave abnormally.

It was changing course and speed under its own power. And it was doing so just days after US Vice-President Mike Pence formally announced plans to create a new Space Force.

Why would it do this? Why the secrecy? Was it some sort of message?

Now, Beijing has declassified tantalizing details of what it calls an artificial-intelligence controlled space clean-up project.

The so-called scavenger program was confirmed in state-controlled media by Luo Jianjun, deputy director of the National Laboratory of Space Flight Dynamics Technology at Northwestern Polytechnical University in Xian.

“We prefer not to talk about it publicly,” he said.

But talk about it he did.

ORBITAL PICK-UP

Referring to the uncontrolled crash of the Tiangong-1 experimental space station last year, Mr. Luo said the use of newly developed technology could guide such craft to burn up in the Earth’s atmosphere safely.

According to the South China Morning Post, he said the project was still experimental and that there had been no large-scale deployment of such orbital robots.

The project involves small satellites — some weighing less than 10kg — with robotic arms and small thrusters. Their sensors and thrusters enable them to approach within 20cm of an object before reaching out and grabbing it.

This could be a cast-off rocket casing. An old satellite with a dead power source. Or a fully-functional military or commercial device.

Once attached, the scavenger can then set about pushing it towards the Earth’s atmosphere — and a fiery fate.

“Most details remain secret because of the technology’s potential military applications,” Mr. Luo states.

WEAPONISED GARBAGE TRUCKS?

The Morning Post also quoted a recently declassified Communist Party document as saying the concept of orbital drones had been under development since 2008.

“The project has not only found applications in more than 10 satellite models … but also drones, smart weapons and robots,” the document reads.

The Centre for Strategic and International Studies (CSIS) states in its 2019 Space Threat Assessment that a Chinese experimental satellite, designated SJ-17, circled a Chinese communications satellite several times in 2017 and 2018.

Any military objective could be similar to that of Russia.

The small robotic devices hide among space junk — or even attached to a bigger object. Here they remain, powered down until awoken by a coded call.

This is because every rocket launch is carefully observed by competing governments and corporations. Whatever ends up in orbit is accurately tracked and recorded — not least to determine if it could end up hitting some high-value target, such as the International Space Station.

But only the most sensitive and comprehensive space junk tracking systems would be capable of detecting the strange appearance or shift in the course of an object so small.

These grapple-equipped gremlins can then pass close to a satellite of interest, photographing and scanning its make-up, or even intercepting its signals. They can also tear away at its surface, damaging sensitive equipment and rendering the satellite useless.

Or, they could grab a dead satellite and propel the junk out of orbit.

BATTLESPACE

In March last year, India launched a missile that successfully destroyed a satellite already in orbit. It is only the fourth nation to do so.

But there was fallout: a great cloud of metallic debris cannoning through space.

Some pieces are just millimeters across. Others, tens of centimeters. All can rip holes in propellant tanks, depressurize a spacecraft — or smash another satellite, causing yet another cloud of debris to erupt.

It joins a hail of some 3000 high-velocity fragments — all of which are being tracked — caused when China conducted a similar ‘kinetic-kill’ test in 2007. It’s estimated a total of more than 600,000 pieces are cannoning about up there.

The risk is, such debris could initiate a runaway chain reaction.

It’s called the Kessler Syndrome, after the researcher who first predicted it.

And, some academics are warning it could soon close access to high orbit within as little as 20 years.

“If the useful orbits around Earth become too full of rubbish, and our satellites can’t operate safely, it will have serious implications,” the Australian Academy of Science warns.

And space agencies around the world, including Australia, are racing to find ways to mitigate the problem. Some, such as the space nets being tested by Britain and repair robots proposed by the US, could also be construed as weapons.

‘SOFT’ OPTIONS

There’s no point winning an orbital war if nobody could ever leave the surface of the Earth again for several thousand years.

Which is why the militaries of such nations such as China, Russia and the United States are looking for less destructive ways to dominate space — including gremlin satellites.

Militaries are exploring other options, such as Russia’s recent controversial jamming of GPS satellites operating above Norway and Sweden.

And then there are lasers. While not yet capable of shooting an object out of space, they can damage or blind the sensors they carry.

“It’s happening all the time at this low level,” Centre for Strategic and International Studies Aerospace Security Project head Todd Harrison told MIT Technology Review. “It’s more grey-zone aggression. Countries are pushing the limits of accepted behavior and challenging norms. They’re staying below the threshold of conflict.”

This story originally appeared in news.com.au.