The Air Force still hasn’t identified the root cause of why an upper stage engine on a Delta IV rocket failed during an October Global Positioning System (GPS) IIF-3 satellite launch.
“The latest is we still don’t have root cause,” Air Force Space Command (AFSPC) chief Gen. William Shelton said yesterday during an Air Force Association breakfast in Arlington, Va.
This could lead to further launch delays as the Air Force said in a Oct. 11 release the “launch manifest schedule” is currently under review while the root cause is determined. The Air Force said it is standard procedure to carefully review all flight data to determine readiness to proceed with the next launch.
Shelton also said he initiated another investigation to get to the bottom of the incident because the Air Force can’t afford launch issues.
“I also kicked off a discretionary accident investigation just to make sure we got all the ‘i’’s dotted and ‘t’’s crossed,” Shelton said.
Shelton ordered an Accident Investigation Board (AIB) to investigate why an upper stage engine on a Delta IV RL-10B-2 rocket did not perform as expected during the Oct. 4 launch of a GPS IIF satellite. Despite the engine not performing as expected, the Delta IV delivered the satellite into its proper orbit.
Once the AIB completes the investigation, it will report its findings to Shelton and, as appropriate, make them available to the public (Defense Daily, Oct. 12).
The Delta IV rocket was manufactured by United Launch Alliance (ULA), a joint venture between Boeing [BA] and Lockheed Martin [LMT]. ULA said an unexpected “data signature” with the engine caused the rocket to experience a reduced thrust level. ULA said it, along with Pratt & Whitney [UTX] Rocketdyne, formed an investigation team to assess all flight and operational data to determine direct and root costs and to identify and implement appropriate corrective action before future flights (Defense Daily, Oct. 11).