Last year, just before the Fourth of July holiday, the US Space Force officially took ownership of a new operating system for the GPS navigation network, raising hopes that one of the military’s most troubled space programs might finally bear fruit.

The GPS Next-Generation Operational Control System, or OCX, is designed for command and control of the military’s constellation of more than 30 GPS satellites. It consists of software to handle new signals and jam-resistant capabilities of the latest generation of GPS satellites, GPS III, which started launching in 2018. The ground segment also includes two master control stations and upgrades to ground monitoring stations around the world, among other hardware elements.

RTX Corporation, formerly known as Raytheon, won a Pentagon contract in 2010 to develop and deliver the control system. The program was supposed to be complete in 2016 at a cost of $3.7 billion. Today, the official cost for the ground system for the GPS III satellites stands at $7.6 billion. RTX is developing an OCX augmentation projected to cost more than $400 million to support a new series of GPS IIIF satellites set to begin launching next year, bringing the total effort to $8 billion.

Although RTX delivered OCX to the Space Force last July, the ground segment remains nonoperational. Nine months later, the Pentagon may soon call it quits on the program. Thomas Ainsworth, assistant secretary of the Air Force for space acquisition and integration, told Congress last week that OCX is still struggling.

Hopes Dashed

The Space Force’s formal acceptance of the ground system from RTX last year marked a turning point for OCX after years of blunders. The handover allowed military teams to validate the new control software and upgraded ground facilities before declaring the system ready for operational service. But this testing uncovered more problems.

“As a result, extensive and more operationally relevant testing with actual GPS satellites, ground antennas, and user equipment led to an increase in finding extensive system issues across all subsystems, many of which have not been resolved,” Ainsworth told the House Subcommittee on Strategic Forces in prepared testimony.

“For over 15 years, the program has experienced significant technical challenges, schedule slips, and associated cost growth, putting at risk the launch and capability of future GPS satellites,” Ainsworth continued.

Delays in the OCX program forced the military to retool the GPS network’s decades-old legacy control system to manage the GPS III satellites. Upgrades in 2020 allowed the Space Force to begin using a subset of the new capabilities enabled by “M-code” GPS signals designed for warfare.

The military-grade signals are especially important now to combat GPS jamming and spoofing around war zones in Ukraine and the Middle East. M-code is more resistant to jamming, and its encryption makes it more difficult to spoof, a kind of attack that makes receivers trust fake navigation signals over real ones. The upgrade also allows the military to deny an adversary access to GPS during conflict, while maintaining the ability for US and allied forces to use M-code for an advantage.

Military officials previously thought they needed OCX up and running to fully exploit M-code signals on approximately 700 types of weapons systems such as airplanes, ships, ground vehicles, and missiles.

Because of its civilian and military importance, the GPS network is an “attractive target for adversaries,” said Lieutenant General Doug Schiess, the Space Force’s deputy chief of operations. “Jamming [denial of signal] and spoofing [false signals] are a current and growing threat to GPS. We are modernizing GPS to mitigate these threats.”

But a key part of the modernization is still plagued by problems. Ainsworth told lawmakers that continuing to update the existing GPS ground control system “is now a viable option as systemic issues with OCX continue.”

This could spell the end for the OCX program. The service is weighing options for how to proceed, including possibly canceling the program entirely, a Space Force spokesperson told Air & Space Forces Magazine.

In a written statement released to Ars Technica, RTX said: “The GPS OCX program is a large-scale, highly complex ground system modernization effort. US Space Force accepted delivery of a mission-capable system in 2025 and assumed operational control at that time. RTX is working alongside the government to address any post-delivery concerns.”

How Did It Come to This?

The Government Accountability Office found that the OCX program was marred by “poor acquisition decisions and a slow recognition of development problems” before it exceeded cost and schedule targets in 2016, triggering an automatic Pentagon review for potential cancellation. The problems included difficulties with the software’s cybersecurity features and a “persistently high software development defect rate.”

At the time, defense officials blamed the troubles on the government’s lack of software expertise and Raytheon’s “poor systems engineering” practices. The military restructured the program and continued development, only to encounter further delays and cost overruns.

“There have been problems in program management, problems with contractor performance, problems in systems engineering, both on government and on the contractor side, over a number of years. It’s a very stressing program,” Ainsworth told lawmakers last week. “We are still considering how to ensure we move forward.”

This story originally appeared on Ars Technica.