The Defense Department's space-based Global Positioning System is aging, and there is concern about the possible loss or degradation of some important services.

At a congressional hearing last week, Cristina T. Chaplain of the Government Accountability Office said it is "uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption." If that happens, she said, "some military operations and some civilian users could be adversely affected" as early as next year.

Lt. Gen. Larry James , the commander of the Joint Functional Command for Space, told the House Oversight and Government Reform subcommittee that some GPS satellite constellations have "exceeded their design life, operate with partial capability, or are a single key component away from failure."

The next generation of satellites is scheduled for launch in November, but is three years behind schedule. The GAO reported that the current Pentagon schedule for the brand new generation of satellites now in development stages is overly optimistic.

For more on GPS worries:
 - see this Government Computer News article