The White House is planning to disable GPS service in the event of a national emergency:

President Bush has ordered plans for temporarily disabling the U.S. network of global positioning satellites during a national crisis to prevent terrorists from using the navigational technology, the White House said Wednesday.

Any shutdown of the network inside the United States would come under only the most remarkable circumstances, said a Bush administration official who spoke to a small group of reporters at the White House on condition of anonymity.

The GPS system is vital to commercial aviation and marine shipping.

The president also instructed the Defense Department to develop plans to disable, in certain areas, an enemy’s access to the U.S. navigational satellites and to similar systems operated by others. The European Union is developing a $4.8 billion program, called Galileo.

The military increasingly uses GPS technology to move troops across large areas and direct bombs and missiles. Any government-ordered shutdown or jamming of the GPS satellites would be done in ways to limit disruptions to navigation and related systems outside the affected area, the White House said.

As much as I understand the need to put a plan like this into place, I have to wonder about the unintended consequences of pulling the plug on such a mission critical service like GPS. It would be especially important during a time of national emergency to help non-terrorists safely arrive at their destinations or to find specific places for medical treatment or rescue, for example. GPS is one of those technologies that everyone loves, but ultimately isn’t as open source as it feels.