When your satellite breaks in space, as DigitalGlobe’s did on Monday, there isn’t an easy way to repair it. Technology that’s currently on the horizon may change that, however, allowing satellite providers to staunch their financial losses and get more out of their investments.
For DigitalGlobe, the loss was brutal: an Earth-imaging satellite called WorldView-4, which had clients that include Google Maps. A critical instrument needed to stabilize the spacecraft has stopped working properly. Now, the satellite can’t take decent pictures of Earth for DigitalGlobe’s customers, and there seems to be no way to fix the damage.
WorldView-4 generated $85 million in revenue for Maxar, DigitalGlobe’s parent company, in fiscal year 2018, and the spacecraft is insured for $183 million. (Maxar says it intends to seek all of that money.) But if a servicing company offered a way to repair the satellite in orbit, for tens of millions of dollars, Maxar wouldn’t be facing as big of a financial hole. WorldView-4 just needs a new working gyroscope to get things up and running again.
As of now, there’s nothing to be done if a satellite fails in orbit and becomes inoperable. The satellite transitions from useful to potentially dangerous; defunct satellites can become space debris, a hazard to functioning spacecraft that can create a collision risk. Such impacts could create thousands of pieces of junk, which then also pose a threat to other vehicles in space. So figuring out how to repair — or at least, clean up — dead satellites is important.
“If I have several hundred satellites in the same orbit that are going to be crossing paths, I want to get the ones that are failed and potential threats out of the way,” Chris Blackerby, the COO of Astroscale, an international company that wants to clean up space debris, tells RR-Magazine. “It’s the same way if I’m a trucking company and my truck fails on the highway; I don’t want to leave it there.”
Several aerospace startups are trying to figure out how to repair satellites, working on technologies that could someday provide a solution for DigitalGlobe and Maxar. These companies propose to build spacecraft that would stay in space and rendezvous with failed satellites. Some will aim to get rid of them by dragging them down closer to Earth so they fall out of orbit and burn up in our planet’s atmosphere. Others suggest another solution: adding replacement parts to the craft so that it can continue working as it was intended.
Fortunately, it seems that WorldView-4 is still within Maxar’s control. One of the satellite’s gyroscopes failed, which is a type of spinning rotor that is used by many spacecraft to help them point. Since WorldView-4 is tasked with taking super precise images of Earth, this failure means the satellite can’t really do its job anymore. Maxar says it has moved the vehicle into a “safe configuration.”
“We will continue to maintain operational control of the satellite and monitor its location and health, but the satellite cannot collect new imagery and will likely not be recoverable,” a spokesperson for Maxar said in a statement to RR-Magazine. So the company could move the spacecraft with the vehicle’s onboard thrusters if needed, possibly depositing it into the atmosphere one day if needed. But if the satellite could be fixed, it would let Maxar continue earning money on its space investment.
This kind of repair job is actually something NASA’s Space Shuttle used to provide. In 1984, astronauts on board the Challenger Space Shuttle used the vehicle’s robotic arm to capture an astronomy satellite that was having some issues in orbit. The crew then refurbished the spacecraft and replaced the systems that weren’t working, before putting it back on its path around Earth. The satellite then continued to work just fine for the next five years.
Since the Space Shuttle has been discontinued, devoted repairs aren’t an option. But this kind of servicing is something that companies like Altius Space Machines in Colorado are hoping to sell someday, just with robotic satellites instead. The routine would be relatively straightforward: launch whatever spare part you need into orbit, a servicing satellite goes to retrieve that part, and the servicer then meets up with the failed satellite and tacks on the part. And if that servicer were in an orbit that lots of other satellites use, it could serve as a repair shop.
Part of the interest in repairs is because it doesn’t take much to make a spacecraft go AWOL. “A lot of times, when a spacecraft fails, it’s only one or two components that die and the rest of the stuff is still working,” Jonathan Goff, president and CEO of Altius Space Machines, tells RR-Magazine.
The technologies needed for such servicing operations aren’t quite fully mature yet, though. Spacecraft will need to be able to rendezvous with satellites and dock with them delicately — at speeds of 17,000 miles per hour or more. Handling all of this autonomously will require a suite of sensors and cameras to help guide the vehicle through space. Then, once a servicing satellite reaches one of its targets, it will need to be able to perform very technical procedures, such as attaching a new piece of hardware or transferring fuel.
Another big problem is accessibility. The satellites that go into space right now aren’t exactly built to be grabbed. WorldView-4 is considered “non-cooperative,” meaning it doesn’t have any features that would allow another spacecraft to dock to it. Many of the satellite servicing companies in the works right now are trying to come up with some kind of standardized interface to solve this problem. The idea is that, in the future, all satellites would be built with an interface that would include some kind of grappling feature.
For Astroscale, grappling would involve some kind of magnet system. That way, the satellites can attach and detach more easily. (Though Astroscale’s mission is less about fixing satellites and more about dragging them to Earth once they break.) “It’s like a car,” says Blackerby. “It has a hitch on it, so if it fails on the highway, AAA can come and tow it away.”
For Altius, which is focused on servicing, its interface would be a little more complex. Not only would it include a grappling system, but also some kind of plug and play port, which would allow a spacecraft to install various electronic devices to a malfunctioning satellite. Plus, the interface would include some kind of system for transferring fluids in case the satellite has run out of propellant. “And these interfaces aren’t just for repairing stuff that broke,” says Goff. “Once you add an interface like this, you can use it to upgrade to increase the functionality of your satellite.”
Since WorldView-4 wasn’t built to be serviceable, its future seems grim. But Goff argues that if it had some kind of plug-in interface, perhaps a new gyro could have been attached to the outside of the satellite. It would require some software tuning, to recalibrate the new shape and weight of the vehicle, as well as the new location of the gyro. “As I understand it, that should be totally possible,” he says. “I can’t really think of hardly any components that moving into the outside would be a huge problem.”
WorldView-4 may be doomed, but other satellites could be saved in the future. There are numerous demonstration missions that are in the works, many of which by Maxar. NASA and Maxar are developing a spacecraft called Restore-L, which will attempt to refuel a government-owned satellite already in orbit called Landsat-7. And Maxar is developing new servicing technologies as well as working on a servicing satellite for DARPA called RSGS. Most of these missions are targeting the early 2020s for launch.
Thinking about all of this now is key, as aerospace companies like SpaceX, OneWeb, Iridium, and more want to send hundreds to thousands of satellites into orbit within the next decade. That will just increase the percentages of probes that break in space. Blackerby says his company has estimated that about 5 to 10 percent of satellites malfunction in some way before their missions have been completed, and he says that’s a conservative number.
“Already, it’s a crowded orbital environment,” says Blackerby. “So having some plan to mitigate the potential for future accidents, it’s going to be vital.”