The Air Force and United Launch Alliance (ULA) successfully launched the service’s ninth Global Positioning System IIF series satellite (GPS IIF-9) Wednesday at 2:36 p.m. EDT from Cape Canaveral Air Force Station, Fla.
Liftoff took place on a Delta IV rocket, the 29th Delta IV launch in ULA’s history and the last with a GPS IIF series satellite. The next launch that will take place at the Cape will be Space Exploration Technologies Corp.’s (SpaceX) sixth Cargo Resupply Services (CRS-6) mission for NASA on April 10. Launch window is scheduled to open at 5:42 p.m. EDT.
There are 12 total satellites in the GPS IIF series, the remaining two are in storage. A GPS IIF launch is set for June, but a date for the final satellite’s launch has not been set.
The Air Force said over the weekend a GPS message indexing error was recently identified and had gone unnoticed since 2013. The error affected a limited number of active IIF series satellites but did not degrade the accuracy of the GPS signal received by users. The service said it implemented a workaround to prevent further messaging indexing violations and is taking steps to permanently correct the error (Defense Daily, March 23).
ULA is a joint venture of Lockheed Martin [LMT] and Boeing [BA]. Boeing develops GPS IIF.