Venerable Delta II Launches Final GPS Satellite

The Air Force launched Aug. 17 the 48th successful and final Air Force Delta II GPS satellite, ending what officials called one of the most successful space launch programs in American history. While the launch concludes the Air Force's use of Delta II as it transitions its systems to Atlas V and Delta IV rockets, the Delta II will still keep launching into the future for NASA and commercial customers.

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A little more than an hour after launch from Cape Canaveral, the Delta II rocket deployed the GPS IIR-21(M) spacecraft, the eighth modernized NAVSTAR Global Positioning System Block II R-M military navigation satellite. GPS is a space-based positioning system designed and operated as a 24-satellite constellation that provides precision navigation and timing information to military and civilian users worldwide.

"One third of the 143 successful Delta II launches were GPS satellites. The ULA Delta team is extremely proud to have launched this incredible constellation," Jim Sponnick, vice president of the Delta Product Line, said in a statement. "During the past two decades, the system has changed how people live their lives on a daily basis. GPS has greatly improved military operations as well as numerous maritime, aircraft, civilian and business operations worldwide."

The first Air Force Delta II GPS launch occurred Feb. 14, 1989. The first launch in 1989 was NAVSTAR II-1.

Designed to operate for 10 years, GPS satellites orbit Earth every 12 hours, emitting continuous navigation signals. Users can receive signals to precisely calculate time, location and velocity. In addition to its military use, GPS satellites also provide directional assistance to civilian users around the world.