At 1338 GMT on 5 February 2016, an Atlas V 401 launch vehicle, operated by the United Launch Alliance (ULA), successfully lifted off from Cape Canaveral Air Station in Florida, USA. Aboard the flight was the GPS IIF-12 satellite, which was being launched into the US Air Force navigation satellite constellation in Medium Earth Orbit of approximately 20,400km altitude. The Atlas flight was reported by ULA to be using a newly designed suite of avionics, flight software and ground systems.
GPS IIF-12 is the final satellite in the IIF-block of satellites, which are GPS satellites that incorporate numerous improvements to provide greater accuracy, increased signals and enhanced performance for users. The Atlas booster for this mission was powered by the RD AMROSS RD-180 engine, and the Centaur upper stage by the Aerojet Rocketdyne RL10C-1 engine.
The threat to the supply of Russian RD-180 engines resulting from moves by US legislators was reportedly used by ULA as a excuse to withdraw itself from a competition with SpaceX, and its very competitive Falcon 9 launch vehicle series, for launches of the next generation GPS III series satellites. It was later claimed by ULA that actually it was an accounting compliance issue that was the cause of this withdrawal. Either way, the withdrawal from the competition led the US Air Force to reconsider giving ULA an annual stipend of US$800 million via its EELV Launch Capability (ELC) contract to support the firm’s operation and infrastructure.
Update on 1 March 2016: The US Air Force continues its efforts to look for a replacement for the RD-180 Atlas V with funds for the main and new upper stage of the Vulcan rocket design. See here
