WASHINGTON — The U.S. Air Force’s fifth Wideband Global Satcom (WGS) X- and Ka-band communications satellite has been scheduled to launch May 8 aboard a Delta 4 rocket in what will be the launcher’s first mission since an October anomaly, the service said in a press release March 29.

During Delta 4’s otherwise successful Oct. 4 launch of the Air Force’s GPS 2F-3 navigation satellite from Florida, the rocket’s Pratt & Whitney Rocketdyne-built RL-10 upper-stage engine underperformed. The incident triggered an investigation that delayed several missions, including WGS as well as launches aboard the Atlas 5 rocket, whose upper stage has some hardware commonality with the Delta 4.

In early December, United Launch Alliance (ULA) of Denver, which manufactures and operates both rockets, said the anomaly was due to a fuel leak in the interior of the RL-10’s thrust chamber.

In its press release, the Air Force said the investigation is expected to wrap up in April.

“Final testing related to the investigation is underway,” the Air Force said. “ULA, Pratt Whitney Rocketdyne, and the Air Force have been working closely on this investigation and have approved processing this mission toward the May 8 launch date.”

The WGS-5 launch had been scheduled for January before the anomaly occurred on the GPS 2F-3 mission.

The Atlas 5 resumed flying in December with the launch of the Air Force’s X-37B spaceplane on a classified mission.

Once in operation, the Boeing-built WGS-5 will join four other WGS satellites on orbit. It will allow users to send images three times faster than current Defense Department data rates, according to a Boeing press release.

WGS-6, meanwhile, has completed testing and also is scheduled to launch this year. Four more satellites, WGS-7, -8, -9 and -10, are in production.

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...