Atlas Is Back With GPS

An Atlas V rocket launches on May 15, carrying the GPS IIF-4 satellite. (Image courtesy United Launch Alliance, LLC.)

“Go Atlas.”

“Go Centaur.”

“Go GPS.”

With those words, the launch team completed its final status check at T-minus 20 seconds. Moments later, for the first time in 28 years, an Atlas rocket powered a Global Positioning System satellite to orbit.

The Atlas V, flying in the the 401 configuration with a standard four-meter-diameter fairing and no strap-on solid rocket motors, lifted off from the Cape Canaveral Complex 41 pad as its launch window opened at 5:39 p.m. ET (2:39 PT) on Wednesday, May 15.

The rocket’s first stage is powered by a single RD-180 engine that burns kerosene and liquid oxygen in two thrust chambers, producing 860,000 pounds of thrust on liftoff. The engine of the Centaur upper stage, to which the GPS spacecraft is attached, burns liquid hydrogen and oxygen.

Ray Johnson, vice president for Space Launch Operations, reported the successful separation of the GPS IIF-4 spacecraft 3½ hours into the mission.

“There were no significant problems or issues,” Johnson said. “I want to congratulate the entire Atlas launch team and the GPS satellite team on this very successful launch.”

Johnson noted that this was the first GPS launch on an Atlas V. Earlier Atlas boosters were used to launch 11 Block 1 series GPS satellites from February 1978 through October 1985. These satellites were used to test the navigation system concept. The current operational GPS satellites have all been launched with Delta rockets, beginning in February 1989.