An unexpected “data signature” with the upper stage engine on a Delta IV rocket caused the launch of the Air Force’s Global Positioning System (GPS) IIF-3 satellite to experience a reduced thrust level, United Launch Alliance (ULA) said in an Oct. 5 statement.
“ULA successfully launched and deployed the GPS IIF-3 satellite in a precise orbit Oct. 4, but during the launch, observed an unexpected data signature with the upper stage engine throughout a portion of the flight,” ULA said in the statement. “The unexpected signature was seen during second stage performance as evidenced by a reduced thrust level of the RL10 engine.”
ULA said the Delta IV’s system design, flight software, vehicle margins and propellant reserves enabled the successful outcome for this mission.
ULA said it, along with Pratt & Whitney [UTX] Rocketdyne, formed a robust investigation team to thoroughly assess all flight and operational data to determine direct and root costs and to identify and implement appropriate corrective action before future flights.
“Though the GPS IIF-3 mission was a complete success, ULA fully understands the challenges of launch and will thoroughly investigate and implement appropriate actions to reliably deliver our customer’s critical capabilities to the orbital positions required,” ULA Vice President of Mission Operations Jim Sponnick said in the statement.
ULA did not respond to an email recently requesting comment. ULA is a joint venture between Boeing [BA] and Lockheed Martin [LMT].