GPS IIF-12: The Prologue


Originally posted February 8, 2016 on LinkedIn.

While last week’s successful launch of the final Boeing Global Positioning System (GPS) Block IIF spacecraft from Cape Canaveral is notable, next weekend is the anniversary of another significant GPS milestone and a related space transportation milestone.

Sunday is the 27th anniversary of the launch of the first operational GPS Block II satellite. Space Vehicle Number (SVN) 14, launched as the NAVSTAR II-1 mission, lifted off from Launch Complex 17A and soared into a clear blue sky over Cape Canaveral Air Force Station at 1:30 PM Eastern on February 14, 1989.

The Valentine’s Day launch culminated three years of launch preparations. Activities leading to this first launch included constructing and activating the Navstar Processing Facility where the combined team of Air Force 6555th Aerospace Test Group (ASTG), spacecraft contractor Rockwell International, and launch vehicle contractor McDonnell-Douglas personnel prepared GPS satellites and Payload Assist Module (PAM) third stages for launch. Integration activities included making the engineering and operational transition from flying GPS satellites on the Space Shuttle as originally intended, to flying them on expendable launch vehicles in the aftermath of the Challenger accident.

The new Block II satellites were to comprise the first truly operational GPS position, navigation, and timing (PNT) system. The Air Force had successfully launched and deployed ten Block I GPS concept validation satellites between 1978 and 1985 (one was lost in an unsuccessful launch in 1981).

The launch vehicle that lofted GPS into orbit that day was the first Delta II rocket flown, a follow on to the venerable Delta rocket. Delta had evolved from the Thor Intermediate Range Ballistic Missile to a workhorse space launch vehicle. Challenger and the subsequent near-term failures in every U.S. expendable launch vehicle system created the need for an alternate path to space. As part of the Air Force Medium Launch Vehicle (MLV) program, McDonnell-Douglas restarted Delta production, but with a stretched first stage and a wider payload fairing. They also upgraded the launch pad and other facilities to accommodate the modified launch system.

The Delta II inauguration would prove a significant milestone in space transportation. Delta II would go on to launch 8 more GPS Block IIs and 40 Block IIA, IIR, and IIR-M satellites, in addition to numerous NASA and commercial satellites.

When Operation Desert Shield began a year and a half later, the planned constellation of Block II satellites was not yet fully deployed. The Air Force would launch three more GPS satellites before Operation Desert Storm began in January 1991. The combination of remaining Block I satellites and the partially deployed constellation of Block II satellites, along with rapidly built up GPS ground equipment, provided a significant contribution to Desert Shield/Desert Storm, in what many have called the first space war.

Of course, GPS has become ubiquitous over the last twenty-seven years, an essential element of the global information infrastructure. GPS reached full operational capacity in 1995. Today, in addition to its availability to U.S. and allied armed forces and approved Government agencies, it is freely available to civilian users on a continuous, worldwide basis. Hundreds of applications affect every aspect of modern life. GPS technology is now in everything from cell phones and wristwatches, bulldozers, shipping containers, and ATM’s. http://www.gps.gov/

All good things come to an end, or at least evolve.

After 11 years of service, SVN 14 was decommissioned on April 14, 2000.

As of this week, two Delta II vehicles remain to be launched. Both are slated for NASA missions. A third vehicle is unassigned and perhaps will never fly.

Delta II successors include the short-lived Delta III and the Delta IV family of vehicles flying today as a result of the Air Force Evolved Expendable Launch Vehicle (EELV) program. Delta IV has successfully launched six GPS IIF satellites and twenty-tree additional operational national security, civil, and commercial missions (plus one demonstration launch of the Delta IV Heavy variant).

The Air Force inactivated the 6555th ASTG on 1 October 1990, but the 45th Launch Group and 45th Operations Group components of the 45th Space Wing continue the mission, as demonstrated with the GPS IIF-12 / Atlas V launch last Friday.

(Author’s note: Then USAF Captain Knauf led the 6555th ASTG’s GPS II-1 team and later held several positions in the EELV program. He is proud to have played a small part in the development and evolution of the nation’s space transportation and GPS capabilities)

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