The U.S. Space Force on Tuesday launched the final satellite in its Global Positioning System (GPS) Block III series, completing a key phase of a long-running effort to modernize the constellation.
The launch concludes the deployment of 10 GPS III satellites, a series intended to incrementally improve positioning accuracy, signal reliability, and resistance to interference. The milestone marks the end of one phase within a broader modernization program that has been underway since 2000.
The satellite lifted off aboard the SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station at 2:53 a.m. ET after a one-day delay due to weather. About 90 minutes after liftoff, it was expected to deploy into medium Earth orbit.
Designated GPS III SV10, the satellite had originally been assigned to the United Launch Alliance Vulcan rocket. The Space Force reassigned the mission to SpaceX in March 2026 following delays in Vulcan’s development schedule.
SpaceX launched nine of the 10 satellites in the series. United Launch Alliance launched GPS III SV02 on August 22, 2019, aboard a Delta IV Medium rocket.
The GPS modernization effort covers satellites, ground systems, and user equipment, spanning multiple generations. The GPS III program is the latest completed block. The SV-10 mission delivered the 10th and final satellite, each designed for a 15-year lifespan, longer than earlier models. Lockheed Martin designed and built all 10 GPS III satellites under a contract awarded in 2008.
The company is currently producing the follow-on GPS IIIF satellites, which are expected to continue incremental upgrades to the system.
“We’re closing out a chapter that has defined the last several years of work for this team,” said U.S. Space Force Col. Stephen Hobbs, commander of Mission Delta 31. “Closing out the GPS III block is not the end of the story, but rather it’s a foundation for what comes next.”
Military connectivity
The GPS III satellites contribute to the deployment of M-Code, a military GPS signal designed to be more resistant to jamming and interference.
“M-Code is critical to what our warfighters on the ground use every day,” Hobbs said. “It’s the more robust anti-jam signal that we use.”
He added that M-Code is currently being broadcast globally in what the Space Force refers to as “alternate mode flex power,” and that additional satellites will expand that capability.
Civilian connectivity
The modernization effort also includes updates for civilian users, including the L5 signal. L5 is designed for safety-critical applications such as aviation and operates on a protected frequency with higher power than legacy signals, which can improve accuracy and reliability.
Full global availability of the L5 signal depends on the number of satellites broadcasting it. Officials have said that at least 24 satellites are required for full coverage.
According to Hobbs, there are currently 11 GPS IIF satellites and 10 GPS III satellites in orbit, for a total of 21 capable of contributing to the signal.
“We’ll at least need three more from the upcoming IIIF satellites to get to that global L5 signal,” he said.
The GPS IIIF series is expected to include 22 additional satellites with further technical upgrades, continuing the phased approach to modernizing the system.