The Gazette, Colorado Springs June 20, 2009
Schriever keeps the world in sync
By Tom Roeder
Circling the planet at 12,600 miles, the 30 satellites that make up the Air Force's Global Positioning System exist in silence.
Little more than flying clocks, their timing signal is broadcast down to the planet, always there, beeping away.
On Earth, fear that those clocks could stop has been expressed - sometimes loudly - in Congressional hearings and fiery debate over the management of the system.
The timing signal, controlled by airmen at Schriever Air Force Base on the plains east of Colorado Springs, was first used exclusively by the military, but has embedded itself in every sector of the modern world.
Most people know about the handy in-car navigation systems the satellites enable. Less known, but more important, is how the timing signal makes cell phone systems, ATMs and even the Internet itself possible.
"It's pervasive," said John Pike, who runs the Virginia-based think tank GlobalSecurity.org.
The concern over whether the Global Positioning System will keep working centers on the age of those orbiting satellites. The oldest one that's still working was launched in 1990, and the 30 satellites are seeing the wear and tear of decades in the harsh environment of space.
Eventually, the nuclear clocks on the two-ton spacecraft wear out. And with a development delay holding up a new series of the satellites, experts at the Government Accountability Office fear that too few of the satellites will be working after 2014 to maintain reliable service.
"I agree it's not a time to panic, but it is a time to be concerned," said Cristina Chaplain who authored the Government Accountability Office report.
Chaplain said a combination of delays and quality control issues could leave the country with fewer than the minimum 24 satellites required to provide adequate service.
The latest generation of satellites, with the first going up this fall, is $870 million over budget and three years behind schedule.
It's risky to rely on an ambitious schedule for building a future series of satellites, Chaplain said, because almost every Air Force satellite project in recent years has been plagued by delays and cost overruns. That creates a likelihood that GPS will fall short of the number of satellites it needs in the next decade because new satellites won't be available for launch, she said.
The Air Force dismisses the fear, with officials in Colorado Springs saying with careful management of satellites already flying, there will be no problem.
They say Chaplain underestimated the Air Force's ability to keep old satellites flying and to get new satellites launched on schedule.
Lt. Col. Deanna Burt, who commands the 140 airmen at Schriever's 2nd Space Operations Squadron who operate the satellites, said she has no worry that service could suffer in the future.
System creeps into modern life
The first GPS satellite rocketed into orbit in 1978.
Its purpose was to allow the military to navigate more simply. It's a high-tech version of early sailors navigating by stars.
The timing signal lets users on the ground know how far they are from the satellite. Knowing the distance to three or more of the satellites allows users to triangulate their location on Earth using fairly simple geometry.
Over time, a wide range of industries found other uses for the timing signal. First came banks, which needed to put a time stamp on transactions. Accurate to the millionth of a second, GPS allowed the creation of automated teller machines and electronic stock trades.
Telephone companies found the signal useful, too. As multiple conversations flow down the same phone line, the GPS time stamp allows computers to keep the conversations properly routed.
The same is true of the Internet, where small packets of computer data blast around the globe like water through a hose, each piece properly ordered by the timing of GPS.
"Almost every aspect of everything we're doing everywhere on the globe is tracked by GPS systems," said Frank Backes, CEO of Braxton Technologies, a Colorado Springs firm that writes software the Air Force uses to manage the satellites.
Since GPS is so widely used, fears that the constellation could fall into trouble are magnified.
"It's supposed to be like the sun rising in the east, like gravity," Pike said. "It's just there."
Piloting satellites from miles away
GPS is always there because of dedicated airmen at Schriever who work amid high security and obscurity.
"We don't see what's happening, but it affects a lot of people," said Senior Airman Jennifer Johnson of Ogden, Utah, a three-year veteran of "flying" GPS satellites.
Crews work 24 hours a day, carefully monitoring the 30 satellites for everything from low batteries to radio signal strength. Twice a day, each satellite is linked up to the ground station at Schriever where controllers update its clock to make sure all 30 operate in perfect synchronicity.
Burt, the squadron commander, said individual operators get to know their satellites the way a person would learn the foibles of an aging Buick.
With some of the satellites pushing two decades since launch, they're given special care. Crews work to conserve batteries by shutting down some on-board systems and baby them through orbital maneuvers to conserve fuel.
The "pilots" sit in an office that looks like a smaller version of NASA's Mission Control.
Most of the time the place is as quiet as a library. Then something goes wrong.
"It can be kind of chaotic if there's a problem or anomaly," said 1st Lt. Cassie Devolites of Vienna, Va., who works to upload information to the satellites.
NASA may be able to repair the Hubble Space Telescope, but GPS satellites fly too high for the Space Shuttle to reach, so all problems - "anomalies" in Air Force lingo - must be fixed by operators communicating from the ground.
The worst anomaly is "losing earth," when a satellite spins away from the planet and shoots its radio waves into the galactic abyss. That requires airmen to take manual control of the craft and carefully maneuver it back into line.
It sounds simple, but each satellite is orbiting at nearly 9,000 mph.
It's seldom the craft are shut down for maintenance. The Air Force keeps a 95 percent readiness rate for the satellites.
They have to work, airmen say, GPS is a weapon of war.
While the Air Force gives its GPS service away to civilians worldwide for peaceful purposes, its primary mission is deadly.
The GPS satellites send out a coded signal for military use that has become famous for guiding bombs and missiles to within inches of targets.
The airmen at Schriever have worked to give commanders in Iraq and Afghanistan the greatest accuracy possible.
With new GPS weapons, fighter pilots have become snipers in the sky who can use a single bomb to blast targets that would have required scores of planes to destroy in past wars.
An Air Force report shows that soldiers in Afghanistan last week called in multiple air strikes on Taliban and Al Qaida forces, all using satellite-guided bombs.
"Enemy personnel offered heavy opposition, opening fire with assault weapons and a crew-served machine gun position, until the aircraft arrived and destroyed their positions and emplacements," the Air Force said in a news release.
Burt calls the satellite control consoles a "weapons system." The crews wear flight suits like their brethren dropping bombs from fighters.
The GPS control facility sits behind a double fence in a building patrolled by armed guards. Keeping a door in the building open more than seconds can trigger a security alert that locks down the base.
Just to get into the place, workers are weighed to ensure they don't bring unauthorized items in or smuggle anything out.
If GPS were to fail, the military, which requires the highest degree of accuracy, would see the worst navigation consequences, the Air Force said.
Civilians only need signals from three satellites to guide their in-car navigation systems. Bombs need four or more satellites overhead to accomplish feats seen in Iraq, like flying through windows and hitting moving enemy trucks.
System will keep working
So will the clocks ever stop, or the GPS system fall into disrepair?
The Air Force says that's an unrealistic doomsday scenario.
Col. Dave Buckman, who oversees the GPS program at Air Force Space Command at Peterson Air Force Base, said the service works constantly to address future shortcomings. Space Command oversees all Air Force satellite programs.
The Government Accountability Office report, he said, held no surprises.
"There wasn't any news in the Government Accountability Office report that we weren't working on," he said.
Pike said the report was based on faulty assumptions that future GPS satellites won't last as long as ones launched earlier.
"I was not able to understand what the excitement was about," he said.
Chaplain, who wrote the report, said she used satellite lifespan estimates from a contractor, which showed a future shortfall in the available number of GPS craft.
"I think it remains to be seen whether they will exceed their life expectancy or not," she said.
Burt said she's not worried. The colonel has seen her airmen bring GPS through troubled times before.
"Don't discount the amazing ability of these airmen to keep these satellites running," she said.
© Copyright 2009, Freedom Communications
