The scheduled launch of a United Launch Alliance (ULA) Delta IV rocket carrying the Air Force’s second GPS III satellite has been delayed until the end of August due to an issue discovered in testing, the alliance said July 17.

The launch of GPS III Space Vehicle 2 was originally scheduled for July 25 but is now targeted for no earlier than Aug. 22, according to a ULA tweet. An anomaly was discovered during component testing at a supplier, “which has created a cross-over concern,” the tweet said. United Launch Alliance is a joint venture formed by Lockheed Martin [LMT] and Boeing [BA].

United Launch Alliance’s Delta IV launches July 28, 2014, from Cape Canaveral Air Force Station, Fla. Photo: ULA.

The component was a common part used in the upper stage of both the Atlas V and Delta IV launch vehicles, said Julie Arnold, ULA spokeswoman in a Wednesday email to Defense Daily. She did not specify what the component was or provide the name of its supplier.

“During final acceptance testing of the component at the supplier, the support equipment measured off-nominal voltage,” she said in the email. “The team is reviewing the data and inspecting the hardware to determine root cause. Additional time is needed to replace and retest the component on the launch vehicle.”

The launch will mark the final payload launch aboard ULA’s Delta IV “Medium+” configuration (Defense Daily, March 21).

Lockheed Martin, the prime contractor for the GPS III program, said the second space vehicle was “ready for launch” July 8 (Defense Daily, July 8). The third GPS III satellite has been declared “available for launch.”