Yikes! Could the sky literally start to fall? According to a new study from the U.S. government accountability office, some important GPS satellites could begin to fail as early as next year, and all sorts of GPS users — public safety, military and consumers — could begin to experience regular blackouts, failures and inaccurate readings.

That's unsettling for everyone, but especially the military and first responders who are now relying on GPS for all sorts of applications — from monitoring criminals to responding to an emergency.

The GAO report, which was presented to Congress, says that the Air Force, which has been in charge of overseeing the constellation of GPS satellites since 1990, has struggled to build new GPS satellites within cost and schedule goals and has faced some major technical problems — as well as contractor problems — that are delaying significant updates to the system.

"It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption," said the report. "If not, some military operations and some civilian users could be adversely affected."

The GAO says the Air Force hasn't executed the necessary actions to keep the constellation of satellites running smoothly. "As a result, the current IIF satellite program has overrun its original cost estimate by about $870 million, and the launch of its first satellite has been delayed to November 2009 — almost three years late," the report stated.

The Air Force is structuring its new GPS IIIA program — a satellite system that will improve accuracy, provide better indoor coverage and improve anti-jam performance — to avoid mistakes made on the current IIF program. The Air Force is trying to deploy these next-generation satellites three years faster than the IIF satellites.

The GAO called this schedule to optimistic, given the program's late start, past trends in space acquisitions and challenges facing the new contractor.

"Of particular concern is leadership for GPS acquisition, as GAO and other studies have found the lack of a single point of authority for space programs and frequent turnover in program managers have hampered requirements setting, funding stability, and resource allocation," the report said.

The GAO said the time period between the contract award and the first launch for the GPS III satellites is shorter than most major space programs. And perhaps the biggest hurdle of all is the fact that contractor experience with GPS III technology at this point is minimal and technologists may need some time to get up to date with the new technology.

Another problem, according to the GAO is that the contractor also is being asked to develop a larger satellite bus to accommodate "future GPS increments" and to increase the power of a new military signal "by a factor of ten."

"In view of these and other schedule issues, we believe that there is little room in the schedule to accommodate difficulties that the contractor or program may face," the report said.

That means if the Air Force doesn't meet proposed timelines, there is an increased possibility that in 2010, old satellites could stop working and not enough satellites will be working in the constellation to ensure adequate GPS service.

The Air Force has established an independent review team to examine the risks of using a smaller constellation of satellites to provide military and civilian GPS services, should a few satellites fail. But the Air Force, according to the GAO report, believes the best course of action is to plow ahead its current schedule for GPS IIIA deployments and mitigate risks associated with that effort. This despite the fact that military field equipment may not be ready for several years to accommodate the new GPS signals, the report said.

The GAO did acknowledge Air Force and DoD efforts in recent years to improve the situation. The agency is recommending that the secretary of defense "appoint a single authority to oversee the development of the GPS system, including DoD space, ground control, and user equipment assets, to ensure that the program is well executed and resourced, and that potential disruptions are minimized."

I have no doubt that the government will be willing to throw all of its best minds and plenty of money at the problem. But if things don't go flawlessly with the GPS IIIA system — which would be remarkable by itself — what impact will that have on U.S. military and first responder operations going forward?

Given the numerous vital applications that depend on GPS, I'm crossing my finger — on both hands — that these older satellites have more life in them.

What do you think? Tell us in the comment box below.