A rocket from the commercial company SpaceX lifted off on Wednesday morning with some 60 satellites aboard. Once they reached low Earth orbit, the satellites were released and began to fan out like a deck of cards.
They follow predictable paths around the Earth, but along the way those paths can cross with other things in orbit — satellites from other companies, old rocket stages, loose bits of metal — and cause a catastrophic collision.
Some satellite operations experts say that all too often, only one thing stands in the way of disaster: an automated email alert sent to the inboxes of operators on the ground.
"That is crazy," says Brian Weeden, director of program planning at the Secure World Foundation, which promotes sustainability in space. "But that's currently the status of things."
Now Weeden and others feel it's time for a hard look at the system for managing space traffic, which they think is ad hoc and ill-prepared for what's to come. In just three launches since November, SpaceX has added nearly 200 satellites to a slice of the sky above Earth that's already pretty congested. It plans to launch hundreds more this year, as does a rival company, OneWeb. Both companies say they are diligently complying with voluntary standards to minimize space debris, but critics say those standards simply aren't adequate.
"We're already out in front of the headlights, so to speak," says Moriba Jah, an expert in orbital mechanics at the University of Texas at Austin. "And I think a major cataclysm of some form will happen in space that will have very long-term consequences."
The closest thing the world has to a space traffic control is the U.S. military's 18th Space Control Squadron. "Currently, we have a catalog of approximately 26,000 objects," says Diana McKissock, who helps oversee what the military calls "space situational awareness." (That's a fancy name for keeping tabs on everything up there that's bigger than about the size of a softball.)
The military tracks all of it with a global network of radars and telescopes. It takes measurements and then feeds them into an old computer. "It was first designed in 1983, but the version that we currently use was considered operational in 1996," McKissock says.
Each day, the computer system calculates thousands of potential collisions between objects and spits out the appropriate warnings.
With SpaceX launching satellites by the dozens, the 18th Space Control Squadron has been put to the test. Each new satellite must be individually identified and tracked by the network long enough to establish its orbital path. SpaceX says it is committed to helping ensure safety in space. The company has been supplying the military with orbital data to speed the identification and tracking process.
"I won't say it's easy," McKissock says. "But I will say when faced with a challenge, it's amazing what innovation can come out of meeting that challenge."
For critics of the current system, the real issues come after possible collisions are identified. Once a warning message is sent, McKissock says, the military has no further role in what happens next. "There is nothing in place after we send those messages to ensure that people are making decisions that benefit the entire space community," she says.
About six months ago, a SpaceX satellite and a European Space Agency satellite were predicted to have a close pass. SpaceX saw an initial email from the military and felt that the two satellites would probably speed by each other at a safe distance. The problem, says Weeden of the Secure World Foundation, was that there was a second email.
"There was a new email they got that had a much closer approach that somehow got trapped in a spam folder or just didn't make it to the right people," he says. "That was a problem."
SpaceX says it has fixed that problem. But Weeden says the real issue runs deeper. There are no standards for how close is too close or what satellite operators should do if they get a notice of a possible collision: "It's up to each and every operator to decide for themselves what they want to do, if anything, in response to those close-approach warnings."
Jah says there's an incentive not to move — because to get out of the way, satellites have to expend some of their precious fuel. "Propellant is like platinum up there," he says. "Whenever my propellant is gone, I'm done. I don't make money or I lose the service." Operators must weigh the risks to their satellite against these very real costs, and they can arrive at different decisions.
SpaceX's new Starlink system is supposed to entail thousands of satellites. The company says it's developing an automated collision-avoidance system so satellites can move themselves out of the way.
But that doesn't satisfy Jah. As many hundreds of new satellites go up this year, he says, the companies can't just make decisions in a vacuum. Often, a company will rely on its own highly accurate data for its satellites — but use lower-quality public data for other objects. Foreign governments also have their own data. All of this means that companies might not reach the same conclusions on the potential for a crash or how to move out of the way.
"Each of them thinks of themselves to be quite smart, and we have the right people to maybe automate maneuvers or figure these things out," he says. "But that's done in the absence of the reasoning of the other people."
Jah believes what's needed is a global set of standards for what data to use and for how close is too close and regulations that clearly lay out the right of way. But, he says, such a system remains far off and there's no obvious international body that could take on the responsibility for such rules.
In the U.S., the Commerce Department might take a larger role. The Trump administration has tasked that department with overseeing commercial uses of space, but it's just getting started. In the meantime, the job of coordinating space traffic remains spread across the military, which monitors for collisions, and the Federal Communications Commission and Federal Aviation Administration, which approve and oversee launches.
Given the current system, Jah worries that a collision is only a matter of time. If it happens, "people will move swiftly to try to do something," he says. "But I think it's going to be reactionary, unfortunately."