New Space Robots Will Fix Satellites, or Maybe Destroy Them


People in the satellite industry are fond of automobile analogies. Like this one: Imagine that you buy a car and need it to run for 15 years, but you can’t change the oil or replace the alternator, let alone refuel it. That, they say, is the state of satellites. Once they’ve slipped the surly bonds of Earth, satellites pretty much just have to work, from the time they unfurl from their rocket fairing to the day they shut down for good.

But engineers now want to make satellites actually like cars: fixable, updatable, soup-up-able. To do that, you need another satellite, a robot that can play doctor, gas station attendant, and person in the parking lot who agrees to give your dead car a push.

Animation by NASA

Right now, two major programs—one headed by NASA and one by Darpa—are aiming to create such servicing satellites. But the complications are not just technical. The kinds of satellites that can sidle up to another orbiter and give it new life could also, technically, scoot up and end its life. Because the technology now exists to build these satellite hackers, we're stuck in a quandary: If your enemy can launch such orbiters, and you don't match them, you run the risk of having your space infrastructure quietly slaughtered.

NASA's peaceful program for satellites with these servicing capabilities is called Restore-L. In a promo video for the program, a white-knight satellite with two robotic arms slowly approaches a smaller spacecraft in distress. Reaching out one of its limbs, it delicately grasps the satellite and pulls it close. The other arm peels back a panel to reveal the fuel tank. When the fill-up is finished, the servicing craft releases the patient from its embrace and pushes off. Easy peasy! The mission is expected to launch in the mid-2020s, and will do a demo with the Landsat-7 satellite.

Meanwhile, over at Darpa, the RSGS—Robotic Servicing of Geosynchronous Satellites—program is set to launch in 2021. It will do what the agency dubs “house calls in space.” RSGS merely gets its seed funding from the government: A private company, SSL, will both build and operate the vehicle, tuning up public and private satellites for a fee.

SSL is also making Restore-L. And the company’s Al Tadros, vice president of space infrastructure and civil space, sees technological utility beyond just fixing what’s broken or filling up an empty tank. Spacecraft, he says, could be much lighter at liftoff if they were half-fueled and then topped off in orbit, making for cheaper launches. Or dexterous space robots could assemble new satellites or giant space telescopes, sent up in pieces like cosmic Ikea furniture.

Most of the talk around servicing satellites has this shiny, affirmative air. But the same type of technology that allows you to get intimate with one satellite and improve it also lets you harm it. Servicing satellites could double as weapons.

Restore-L and RSGS’s maker doesn’t put much weight to that argument. They're not designed for that, he says. "Just about anything could be seen as a weapon," says Tadros. "My kids throw their toys at me, and I’m sure that wasn’t the designer’s intent, but it hurts."

Besides, he says, people on Earth—governments, as well as amateur satellite-spotters—are watching what happens up there. It’s hard to hide in space. In part because of that transparency, operators tend to play nice. "There’s already kind of an implied trust there that people are behaving," says Tadros.

"There are a lot of cheaper ways to make a weapon than billion-dollar satellite servicing," he adds. "But maybe I’m not a criminal mind."

Still, Darpa realizes the situation in space is touchy. Soon after the agency started RSGS, it also funded a kind of consciousness-raising group to talk through complications and come up with best practices. It’s called Confers, which is (of course) an acronym, standing for Consortium for Execution of Rendezvous and Servicing Operations.

Brian Weeden, who works at the Secure World Foundation, a think tank, heads the group, which currently has 11 companies on the roster. "We’re focused on a level of transparency that’s going to assuage concerns," says Weeden, "and will create confidence that these companies are doing what they’re supposed to be doing."

There’s a loud voice of dissent out there. That voice bellows from Brian Chow, a policy analyst who’s written extensively about the threat that servicing satellites can pose, in academic papers and op-eds. He uses terms like "space stalkers," "the silent Apocalypse Next," and "Pearl Harbor in Space." He is not kidding around.

"When you talk about a major technology revolution, it comes with good and bad," says Chow. But this time, it's different: The good and the bad are identical twins. "It’s not two different applications in two different systems," he says, like nuclear bombs and nuclear power. A space servicer is, by its very design, a space stalker.

Because servicing satellites have a peaceful purpose, it's not practical to ban them. That, says Chow, makes them the perfect cover. Launch 'em. Say, "They’re for servicing!" Service something sometimes. Then go bend the antenna on a foe's GPS satellite.

And while, of course, the US is not always a stand-up actor, Chow is concerned about China and Russia, where engineers are also developing and launching such satellites, and their militaries are more enmeshed with even the peaceful parts of the space programs. "At a moment’s notice, at any time, they can just redirect those things," he says.

Amateurs on the internet and the Air Force could see that redirection. Satellites, streaking across the sky faster than stars, are often visible from the ground, even with the naked eye. Their radio communications can sometimes be intercepted with homemade antennas. If you're more sophisticated, like the Air Force, you can use big telescopes and radar systems to watch passively and ping satellites like you would ships. But while the Outer Space Treaty prohibits harmful interference (like breaking antennas), no definitive laws spell out when to perceive proximity as a threat, and react accordingly. Respond too soon and you could set off an international incident.

A few solutions exist, as Chow sees it: Establish "self-defense zones" around satellites, a circumference beyond which the US could take action if sufficiently threatened. The specific size of that zone would be for others to decide, but right now, if two satellites could probably come within a kilometer or so of each other, the Joint Space Operations Center sends its highest-level emergency message. And if the US establishes these zones, says Chow, the country should pledge to give the same space to others.

More proactively, Chow suggests that future copies of RSGS-type spacecraft could act as bodyguards, a standing deterrence army commensurate with the number of foreign (potential) space stalkers.

Already, the Pentagon's interest in servicing satellites is likely not completely benign. After all, the D in Darpa stands for "defense," not "dulcet." Commentators called a previous Darpa servicing program "the future of anti-satellite weapons" and "a wrestler's arm, about to toss an opponent out of the ring." And in the late '90s, the Air Force wished for deployment of "satellites to intercept, image and, if needed, take action against a target satellite." Now even more than then, the highest officials see space as a contested domain (see: Space Force).

But the seeds of that viewpoint existed from the start. It’s always been politically fraught up there, from the launch of Sputnik to the leak in the Space Station. The toy designer can say they didn’t intend for the toy to become a projectile, but that won't stop it from bonking you in the head.

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