Twenty-fifth Delta IV launches Block IIF GPS satellite

A Delta IV rocket lifts-off from Cape Canaveral on February 20. (ULA)

CAPE CANAVERAL, Fla. (Updated) -- A new Global Positing System satellite was placed into orbit on Thursday evening to expand location services for both the Air Force and commercial users.

Concerns over solar radiation trends at the opening of the 19 minute launch window forced the launch team to extend the countdown's hold until the final minutes of the window.

Loaded with a platform of new technologies, GPS-IIF-5 satellite will replace an aging GPS spacecraft launched in 1997 and includes the recently upgraded L5 signal for commercial and civil aircraft.

America's GPS operates with twenty-four satellites in six different regions of the globe, with four each plotting exact locations. The new block IIF satellites use the newer L5 civil signal in the Aeronautical Radio Navigation Services frequency of 1176.45 MHz.

The United Launch Alliance's Delta IV-Medium lifted-off at 8:59:00 p.m. EST, at the close of the launch window, beginning the Delta IV program's 25th flight.

The Delta's core booster engine ignited a few seconds prior to T-zero, followed by the ignition of it's twin solid rocket boosters at the moment of lift-off.

"I am pleased with the outcome of today's launch," stated the director of the Space and Missile Systems Center's Global Positioning Systems Directorate Col. Bill Cooley. "The new capabilities provided by the IIF satellites will improve operations, sustainment and overall GPS service for the warfighter, international, commercial and civil communities."

Darkness briefly turned to day as the 206-foot rocket arose from it's seaside launch pad a top 1.25 million pounds of thrust and into the night skies over Cape Canaveral.

Nearly 100 seconds into it's silver flight, the Delta IV twin SRB's had exhausted it's fuel and cleanly separated.

It's cryo fueled first stage's core engine then shut down minutes later and separated as the rocket soared southeasterly toward the central Atlantic Ocean.

The GPS-IIF-5 satellite will also offer the U.S. military's M-code service during it's planned 12 year life.

"The modernized capabilities that are coming on board with the successful launch of GPS IIF-5 will support the worldwide GPS community for years to come," Cooley added following the satellite's deployment.

Spacecraft separation from the Delta's upper stage occurred at 12:32:05 a.m. on Friday, as it arrived in a planned operational altitude of 12,712.6 miles over the Sea of Japan.
The spacecraft will undergo several weeks of testing prior to becoming operational, the Air Force stated.

The Air Force will continue to add replacement GPS satellites as IIF-6 is scheduled to lift-off in May, followed by IIF-7 this summer.

(Charles Atkeison reports on aerospace, science and technology. Follow his updates via Twitter @AbsolutSpaceGuy.)