Right now, hundreds of thousands of objects are zipping around the Earth at orbital velocity. Some of them are satellites, some are dead rockets, and some are merely debris. Most of them, however, are never tracked by anyone. And many of them present a natural hazard, or potentially a deliberate threat, to our assets.
“Nobody is able to achieve persistent monitoring of everything all the time,” says Moriba Jah, associate professor of aerospace engineering at the University of Texas at Austin. “So there’s gaps. That’s part of the paranoia of the US government.”
The united States controls a sophisticated network of radars and telescopes on the ground, but the radars don’t capture everything, and the telescopes mostly work at night. Moreover, assuming they do track something, their measurements are generally inaccurate. “It’s like taking glasses and rubbing a Hershey bar on them,” Jah says.
A ground sensor tracking a satellite in low Earth orbit is probably off by about 100 m, and that estimate gets worse the farther away the satellite is. “Altogether, we really don’t have that great data,” says Brian Weeden, director of program planning at Secure World Foundation, an NGO that promotes space sustainability and security. “I think I would give it a four out of 10.”
Out of the hundreds of thousands of objects orbiting the Earth, the US military only tracks around 24-25,000. The rest are less than 10 cm large, or roughly the size of a softball, too small for the sensors to pick up. But even a quarter flying at 17,000 mph can damage a satellite, and without the data to know where it is, space becomes a hostile environment.
“We can’t avoid collisions unless we know not only where stuff is, but where it is going,” says Weeden.
An object’s location and trajectory are only one piece of the picture, though. We may be able to roughly measure an object’s orbit, but that tells us nothing about who owns it, what it can do, or what its purpose is. This problem Jah calls “the identity crisis.” With no knowledge of an object’s characteristics, there is no way to distinguish a shard of metal from a functional satellite. “So in a Shakespearean sense,” Jah says,” debris or not debris? That is the question.”
As of now, the US military publically catalogues about 21,900 objects in space. That leaves roughly 3-4000 objects larger than 10 cm that are being tracked, but whose identities are unknown. To Jah, this blind spot represents not just a mild concern, a security threat.
“The danger is misinterpretation, miscommunication, and escalation of behavior in space,” he says. “It’s like, ah, here’s this Chinese satellite that’s coming close to my American satellite. Why are they doing this? Are they trying to spy on me or hurt my satellite?”
Weeden expresses more skepticism about the threat of nefarious activity. “I think that’s highly unlikely,” he says. “There are some people who are worried about that, but it’s much more about avoiding collisions… There’s just no examples of somebody destroying someone else’s satellite. You could get a lot of the same effects just by jamming the signals, or interfering with them on the ground.”
Regardless of the likelihood of an attack, the mere uncertainty creates tension. “You don’t have continuous supervision,” Jah says. “So when an anomaly happens, it’s hard to tell whether it was something intentional or an act of God.” To remedy this, he prescribes what is known as a knowledge graph.
“A knowledge graph is a graph database with an ontology or schema put on top of it, semantically linking things together,” he explains. “It facilitates big data analytics.” To translate that into English, a knowledge graph is a framework that links together different kinds of data to see how they are related. For example, it could take satellite locations, ownerships and capabilities, then connect them all together to see who owns which satellite and what it can do. Each piece of information is only somewhat helpful on its own, but infinitely useful put together.
“That’s the Holy Grail,” Weeden says. “There’s this whole other suite of stuff you could be collecting data on that gives you a much better picture of what something is and what it’s doing.” So the question is: why has nobody linked that data together yet?
Part of the answer has to do with antiquated technology. “software development is one area where the Pentagon consistently falls on its ass,” Weeden says. “To give an example, when I was in the Air Force in 2004, we got told, ‘we’re going to train you to use these two computer systems, but don’t get attached because they’re getting replaced with something else in 2005.’ When I left in 2007, we were still using those two systems. And as far as I know, they’re still being used operationally.”
Another part of the answer has to do with a lack of international cooperation. “There’s not a lot of incentives to make the data available,” Weeden explains. Governments don’t want to disclose how much they know or expose operational secrets, and private companies don’t want to publicize anomalies with their assets because it might trigger insurance markets or cause bad PR. There are some commercial sellers of data, but they won’t give up their property without compensation.
Space is becoming increasingly militarized, and if states want to enforce arms controls in that domain, they will first need to monitor it. “There’s no global pool of observational data,” Jah laments. And an effective regulatory regime in space will be nearly impossible without it. As it stands, the vast expanse outside the Earth’s atmosphere, despite being vital to our internet, telecommunications, GPS, and countless other technologies, is the new wild west.
As space debris accumulates and more objects are launched into orbit, the environment is becoming more complex. State and private actors alike have been less than scrupulous with properly disposing of junk assets. The US, Russia, China and India have conducted over 70 anti-satellite tests since 1959, with 20 occuring since 2005, and blowing up satellites unsurprisingly creates a lot of debris.
International regulators can’t control the growth of debris until they can hold culprits accountable. And that, Jah says, is a very difficult task without knowledge graphs. “Who’s tracking this? Who’s making the links? Nobody’s doing that,” he says. “The world’s f#@%!&%g blind to this! It’s crazy.”