WASHINGTON — Launch of the U.S. Air Force’s fifth Wideband Global Satcom (WGS) X- and Ka-band communications satellite will be delayed until at least late March due to ongoing industry and government investigations of the spacecraft’s Delta 4 carrier rocket, according to United Launch Alliance (ULA).
“There is more work to be done to close the investigation overall and to clear Delta missions for launch,” ULA spokeswoman Jessica Rye said in a Jan. 3 email. “Preparations are underway for some engine testing over the next couple months to further refine the investigation conclusions. As a result of this testing and other investigation related activities, the WGS-5 launch will be no earlier than late March.”
ULA manufactures and operates the Delta 4 and Atlas 5 rockets that launch the vast majority of U.S. government satellites.
During Delta 4’s otherwise successful Oct. 4 launch of the Air Force’s GPS 2F-3 satellite from Florida, the rocket’s Pratt & Whitney Rocketdyne-built RL-10 upper-stage engine underperformed. In early December, ULA said the anomaly was due to a fuel leak in the interior of the RL-10’s thrust chamber.
Delta 4 has been grounded while ULA and the military conduct separate investigations of the incident.
The WGS-5 launch was scheduled for January before the anomaly occurred on the GPS 2F-3 mission.
The Atlas 5 rocket, which in addition to military launches is used for many NASA science missions, uses a different variant of the RL-10 in its own upper stage. An Atlas 5 in mid-December launched the Air Force’s X-37B spaceplane on a classified mission after a brief delay related to the Delta 4 anomaly.
Atlas 5’s next two flights are for civilian agencies. On Jan. 30, the rocket will launch NASA’s Tracking and Data Relay Satellite-K from Cape Canaveral Air Force Station, Fla. The satellite will be the latest addition to a constellation NASA uses to communicate with spacecraft in low Earth orbit.
On Feb. 11, an Atlas 5 is scheduled to launch the Landsat Data Continuity Mission from Vandenberg Air Force Base, Calif. The craft will be the eighth in the long-running Landsat Earth observation program, which is managed by the U.S. Geological Survey.
“We are in the process of completing some final action items over the next week that are expected to result in final flight clearance for ULA and NASA for the upcoming Tracking and Data Relay Satellite-K and Landsat Data Continuity Mission missions launching on Atlas,” Rye said.
