Assured access to space A military satellite waiting to launch with ULA will now fly with SpaceX The Space Force wants to launch this particular GPS satellite soon, but ULA isn't ready. Stephen Clark – Apr 7, 2025 8:08 pm | 9 The second flight of United Launch Alliance's Vulcan rocket took off in October. The test flight was successful despite a malfunction with one of its solid rocket boosters. Credit: United Launch Alliance The second flight of United Launch Alliance's Vulcan rocket took off in October. The test flight was successful despite a malfunction with one of its solid rocket boosters. Credit: United Launch Alliance Story text Size Small Standard Large Width * Standard Wide Links Standard Orange * Subscribers only   Learn more For the second time in six months, SpaceX will deploy a US military satellite that was sitting in storage, waiting for a slot on United Launch Alliance's launch schedule. Space Systems Command, which oversees the military's launch program, announced Monday that it is reassigning the launch of a Global Positioning System satellite from ULA's Vulcan rocket to SpaceX's Falcon 9. This satellite, designated GPS III SV-08 (Space Vehicle-08), will join the Space Force's fleet of navigation satellites beaming positioning and timing signals for military and civilian users around the world. The Space Force booked the Vulcan rocket to launch this spacecraft in 2023, when ULA hoped to begin flying military satellites on its new rocket by mid-2024. The Vulcan rocket is now scheduled to launch its first national security mission around the middle of this year, following the Space Force's certification of ULA's new launcher last month. The "launch vehicle trade" allows the Space Force to launch the GPS III SV-08 satellite from Cape Canaveral, Florida, as soon as the end of May, according to a press release. “Capability sitting on the ground” With Vulcan now cleared to launch military missions, officials are hopeful ULA can ramp up the rocket's flight cadence. Vulcan launched on two demonstration flights last year, and ULA eventually wants to launch Vulcan twice per month. ULA engineers have their work cut out for them. The company's Vulcan backlog now stands at 89 missions, following the Space Force's announcement last week of 19 additional launches awarded to ULA. Last year, the Pentagon's chief acquisition official for space wrote a letter to ULA's owners—Boeing and Lockheed Martin—expressing concern about ULA's ability to scale the manufacturing of the Vulcan rocket. "Currently there is military satellite capability sitting on the ground due to Vulcan delays," Frank Calvelli, the Pentagon's chief of space acquisition, wrote in the letter. Vulcan may finally be on the cusp of delivering for the Space Force, but there are several military payloads in the queue to launch on Vulcan before GPS III SV-08, which was complete and in storage at its Lockheed Martin factory in Colorado. Col. Jim Horne, senior materiel leader of launch execution, said in a statement that the rocket swap showcases the Space Force's ability to launch in three months from call-up, compared to the typical planning cycle of two years. "It highlights another instance of the Space Force's ability to complete high-priority launches on a rapid timescale, which demonstrates the capability to respond to emergent constellation needs as rapidly as Space Vehicle readiness allows," Horne said. The Space Force did the same thing last year, when teams from the military, SpaceX, and Lockheed Martin pulled a GPS satellite out of storage and prepared it for launch on a Falcon 9 rocket in less than five months, instead of waiting for its previously assigned slot with United Launch Alliance. Officials dubbed the exercise a "Rapid Response Trailblazer" that could be replicated to fulfill future military needs. The trailblazer mission successfully launched in December. Aside from proving the Space Force could prepare for a launch in a matter of a few months, Horne said the mission also demonstrated the Space Force's ability to adjust its manifest to minimize the impact of Vulcan delays. The GPS III SV-08 satellite shipped to Cape Canaveral Space Force Station, Florida, last week in preparation for launch at the end of May. Credit: Lockheed Martin In exchange for switching the next GPS satellite to launch on a Falcon 9, the Space Force will move a future GPS payload from SpaceX's Falcon Heavy back to ULA's Vulcan. That means the next three GPS satellites will fly on Vulcan. The Space Force compensated ULA for losing a GPS launch to last year's trailblazing SpaceX mission by reallocating another future GPS satellite to Vulcan. Space Systems Command said accelerating the GPS launch campaign must overcome "challenges such as space vehicle-to-launch vehicle integration, satellite control preparation, and rapid contracting and procurement actions." This satellite, No. 8 of 10 in the GPS III series, will replace an aging navigation satellite in the constellation. The GPS network has 31 operational satellites (it needs 24 for global coverage), but some of them are quite old. The longest-lived member of the GPS constellation launched in 1997, and was built for a design life of seven-and-a-half years. The GPS III satellites broadcast more accurate navigation signals, and they're more difficult for an adversary to jam. This generation of GPS satellites also has a new channel compatible with Europe's Galileo navigation network, allowing users to merge signals from both constellations to derive even better position estimates. So, there's a hunger to launch these modernized GPS III satellites. There are two more satellites in this series after GPS III SV-08. They're both finished and in storage, waiting for launch on Vulcan. An upgraded GPS design, known as GPS IIIF, will begin launching in 2027. Stephen Clark Space Reporter Stephen Clark Space Reporter Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet. 9 Comments