GPS
The handy navigating device in nearly every car and Smartphone was also originally developed by the Defense Department in the 1970s to follow the exact locations of nuclear missiles and calculate their proper trajectories. Funding for the system was constantly questioned, however, given how expensive GPS satellites are to build and launch. Today, many GPS satellites are aging and the system is in desperate need of an upgrade, according to the Government Accountability Office. Doing so could cost the Air Force $5.5 billion.
