The U.S. Defense Department has formally halted OCX (Operational Control Segment), a next-generation ground control system for the U.S. military’s GPS satellite navigation network.

IT outlet Ars Technica reported on April 20 local time that the U.S. Space Force said the Defense Department decided on April 17 to end OCX due to long-running technical problems.

OCX was a large project for a next-generation GPS operations control system. It was to process new signals from the latest GPS III satellites and include software to command and control the satellite constellation, ground control stations and upgrades to monitoring sites worldwide. The Defense Department awarded the project in 2010 to Raytheon, now RTX, targeting completion in 2016 and a total cost of $3.7 billion, but government spending had risen to about $6.27 billion by the time of the termination decision and the total cost to complete was estimated to be close to $8 billion.

The project fell well behind on both schedule and cost. Raytheon, renamed RTX, delivered the system to the Space Force only in 2025, but integration tests later found it was not ready for operational use. Col. Stephen Hobbs (스티븐 홉스) of Mission Delta 31, which operates the GPS satellite constellation, said, "Widespread system issues occurred," adding, "Despite repeated fixes, incorporation within the operational schedule proved to be an effectively impossible task."

The Space Force said it found risk factors that went beyond simple delays and could affect the military and civilian functions of the existing GPS. Hobbs said issues identified in some functional areas could jeopardise currently operating GPS capabilities.

The Defense Department and the Space Force will instead focus on improving and advancing the decades-old existing GPS control system. The Space Force said it has already applied some performance improvements through an "architecture evolution plan" and will use that as a basis to gradually employ the latest satellite functions, including the military M-code signal that is more resistant to jamming and spoofing.

The decision also aligns with recent changes in the Space Force’s procurement strategy. It is moving away from long-term investment in a single large programme and toward an incremental approach that divides capabilities and deploys them quickly. Tom Ainsworth (톰 에인스워스), assistant secretary of the Air Force for space acquisition and integration, stressed the need to deliver capabilities quickly rather than rely on complex, all-in-one systems.

Follow-on work is already under way. The Space Force signed a $105 million contract with Lockheed Martin earlier this month and began upgrades to ground systems that will support early operations of the next-generation GPS IIIF satellites. Launches of GPS IIIF satellites are set to begin next year, and the final satellite in the GPS III series is also preparing for launch.

OCX had been cited as a representative long-delayed programme at the Defense Department. The department considered cancelling it once in 2016 but continued after restructuring. The U.S. Government Accountability Office at the time cited flawed acquisition decisions and persistently high software defect rates as causes. The 16-year programme ultimately ended without leaving a dedicated control system for the latest satellites, concluding instead with a shift toward extending and upgrading the existing system.