Launch of last GPS IIF satellite shifts to Friday

February 2, 2016  - By

The U.S. Air Force plans to launch the 12th — and final — satellite in the Block IIF series of modernized GPS spacecraft this week. Originally scheduled to launch Feb. 3, the launch has been moved to Friday, Feb. 5. According to United Launch Alliance (ULA), the cause for the schedule slip was “concerns over the integrity of electrical connectors on the Atlas V booster.”

The Air Force has produced 12 IIF satellites, featuring new clocks, new civil and military signals, and other upgrades for enhanced accuracy and robustness. Currently, 31 GPS satellites are in operational service, including 11 Block IIF satellites and 20 spacecraft from previous generations.

The Air Force Second Space Operations Squadron (2SOPS) indicates that IIF-12 (SVN-70/PRN-32) will replace SVN-41/PRN-14 in the F plane, slot F1. SVN-41 will be re-phased from the F1 location to a newly defined F7 node (GLAN = 45°) once SVN-70 is set healthy.

Meanwhile, SVN-23/PRN-32 (IIA-10) will be taken out of the operational constellation before IIF-12’s launch and sent to Launch, Anomaly, Resolution, and Disposal Operations (LADO).

“SVN-23, launched on Nov. 26, 1990, has been an ‘Iron Bird’ workhorse in the E-plane and has successfully served the world’s GPS users for over 25 years,” said Rick Hamilton, CGSIC Executive Secretariat, in an email. “This is over 18 years past its designed service life, having operationally outlasted (and, in many cases, outperformed) its peers on-orbit due to the diligent efforts of the men and women of the U.S. Air Force.”

PRN-04 is tentatively scheduled for assignment to the first of the new generation of GPS-III satellites, available for launch sometime in 2017.

Date/Site/Launch Time: Wednesday, Feb. 03, 2016, from Space Launch Complex-41 at Cape Canaveral Air Force Station, Florida. The 19-minute launch window opens at 8:38 a.m. EST, and a ULA webcast will start at 8:18 a.m. EST.

Rocket/Payload: A United Launch Alliance Atlas V 401 will launch the GPS IIF-12 mission for the U.S. Air Force.

Launch Updates: To keep up to speed with updates to the launch countdown, dial the ULA launch hotline at 1-877-852-4321 or join the conversation at, and; hashtags #GPSIIF12 and #AtlasV.

Source: GPS world staff

The Air Force’s twelfth Global Positioning System (GPS) IIF satellite is encapsulated inside an Atlas V 4-meter payload fairing. (Photo: ULA)