GPS satellite approaching 23 years on orbit

by Scott Prater
Schriever Sentinel

11/26/2013 - SCHRIEVER AIR FORCE BASE, Colo.  -- As members of the 2nd Space Operations Squadron recognize and celebrate Global Positioning System Satellite Vehicle Number-23's 23rd birthday Nov. 26, they'll do so with fond memories of the satellite's service to military and civilian users throughout the world.

Launched on Nov. 26, 1990, SVN-23 gave military and civilian users another tool for determining position, navigation and timing, but during its 20-plus-year life, it also represented the GPS team 2 SOPS' ingenuity, innovation and problem-solving abilities.

One of the first GPS Block IIA vehicles to reach orbit, SVN-23 represented the latest GPS technology and introduced new sensors and longer lasting data processing memory.

Ted Mogey worked in the squadron as a contractor engineer and Mark Drake served as a satellite vehicle operator. Mogey and Drake powered up SVN-23's payload for the first time in 1990 and still support the vehicle today.

This is more than another birthday. Boeing engineers designed SVN-23 to perform its duties for more than 7 years. In operation for more than three times its expected life, SVN-23 still orbits Earth twice every day, providing position, navigation and timing to approximately 3 billion users worldwide.

Its longevity of service has had its share of challenges.

On Dec. 23, 1993, 2 SOPs operators noticed something amiss. Analysts and engineers in the squadron eventually determined that one of the vehicle's solar-array wings had suffered an electronics malfunction, so manual positioning [or slewing] of its arrays ensued for many years.

"Remarkably, the 2 SOPS/2nd Space Control Squadron team kept finding ways to keep the satellite operating," said Lt. Col. Matthew Brandt, 2 SOPS director of operations. "By the end of 2001, they determined the arrays had degraded to the point that SVN-23 could no longer be operated under a slewing regime."

The vehicle was transferred to the 1st Space Operations Squadron for anomaly and disposal operations. Engineers put its solar arrays into dormant mode and turned off the satellite's payload.

During the next few years, however, 2 SOPS team members figured out a way to solve the problem. They recalled the satellite from 1 SOPS and powered the payload back up in June 2007.

It has been providing GPS signals ever since. In fact, it features the most accurate time keeping of any GPS IIA vehicle on orbit.

"We've reached a point in space operations, much like in the flying community, that our satellites are sometimes older than their operators," said Lt. Col. Thomas Ste. Marie, 2 SOPS commander. "I was a member of 2 SOPS as a second lieutenant when this satellite flew past its design life in 1998. It's simply amazing that a vehicle designed to last seven and half years has made it to its 23rd birthday. It is a credit to the operators, analysts, maintainers and engineers on both the government and contractor sides who all worked to diligently to preserve its mission capabilities."