WASHINGTON — Satellites are notoriously hard to upgrade.

Located anywhere from hundreds of miles to tens of thousands of miles above the Earth’s surface, the machines are difficult to reach physically. For years, engineers have designed satellites with the expectation that the hardware and software they put on orbit with a satellite is all they’d get. That incentivized exquisite satellite designs, built to last many years in space before finally being replaced by a satellite with upgraded technologies.

That mindset has started to change in recent years. Companies including Northrop Grumman and Astroscale are pioneering new on-orbit services that could enable everything from supplemental fuel for maneuvering to satellite repairs using mechanical arms. On the software side, companies are embracing software-defined payloads that the military can reconfigure for new uses using the hardware on orbit.

The U.S. Space Force is investing in those efforts. And the Defense Advanced Research Projects Agency is investing in robotic arms that could revolutionize the ability to repair satellites in space. On the software side, the GPS III satellites, the latest generation launched by the military, feature a 70 percent digital mission data unit, the main piece of the navigation system. GPS IIIF — which will follow after the GPS III series — satellites will feature fully digital navigation payloads built by L3Harris, give operators on the ground more flexibility in how they use the satellites.

But there’s only so much you can change with software alone, and in the end on-orbit GPS satellites are limited by their hardware. However, that may soon change.

Later this year, Lockheed Martin will launch a pair of small cubesat experiments that could pave the way for on-orbit hardware upgrades for GPS satellites, and possibly other Space Force satellites. In short, the company wants to take new hardware (be it a new sensor, data storage, a processor or something else), integrate it with a cubesat, and then plug the cubesat into the GPS satellite via a port on the bus on orbit. Perhaps the cubesat remains connected for the remainder of the satellite’s service life, or perhaps it undocks once a specific mission is complete.

“When we and others build satellites today, they launched with what they’ve got. That’s starting to change with things like software definition,” David Barnhart, Lockheed Martin director of space technology demonstrations, told C4ISRNET ahead of the 36th annual Space Symposium. “But this is essentially significant because it’s the first time that you can really effectively upgrade the hardware.”

The two 12U cubesats — each around the size of a four-slice toaster — that make up Lockheed Martin’s In-space Upgrade Satellite System, or LINUSS, are part of a series of demonstrations that will lead up to the first on-orbit upgrade, which will take place with the 13th GPS IIIF space vehicle. LINUSS will launch into geosynchronous orbit where it will test the precise orbital maneuvers that will be needed to plug the cubesat into the GPS satellite. Lockheed Martin expects to complete the LINUSS mission in two months, although the cubesats could be used for additional experiments in the weeks and months afterward.

The key enabling technology for this satellite upgrade approach is the company’s Augmentation System Port Interface. ASPIN is the docking part where the cubesats will plug into the satellite bus.

“So I kind of think of it like a USB port,” said Barnhart. “You buy your computer, you bring it home, and you want to add something. Like maybe your computer doesn’t have a camera or you want a better camera so you plug in the USB device, and all of a sudden your computer has a new capability it didn’t have out of the box. And that’s kind of the same concept with ASPIN.”

Barnhart added that the ASPIN capability will be part of the baseline for the LM 2100 bus, which Lockheed Martin will use for satellites it’s building for GPS and the Space Force’s Next Generation Overhead Persistent Infrared missile warning system. Future satellites built on that bus will be able to use the on-orbit upgrade capability. Importantly, other companies will be able to build technologies that can plug into ASPIN, meaning that third-party companies can theoretically upgrade Lockheed Martin-built GPS satellites with their technologies.

“All of our LM2100 buses are very long life, and so we’re trying to ensure that they are technically relevant, you know, throughout the entire lifetime by being able to bring up new capability early in the mission, midway in the mission, even at the end of the mission lifetime, by swapping in and out hardware,” said Barnhart.

“And it’s really not just in-orbit upgrading, it’s the possibility of being able to test sensors on production systems in an easier way. [It] is a huge benefit to our customers,” added Barnhart.

The company has several demonstrations planned to build the capability for GPS IIIF space vehicle 13. Barnhart said he expects the company to release a full road map later this year.

In addition to the maneuvering demonstration, LINUSS will also test new high-performance onboard processing capabilities, low-toxicity propulsion, inertial measurement capabilities, and 3-D printed components. It will also showcase Lockheed Martin’s software-defined satellite technology, SmartSat.

Nathan Strout covers space, unmanned and intelligence systems for C4ISRNET.

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