In 1973, the U.S. Department of Defense invested $12B to develop a space-based navigation system known as Global Positioning System (GPS). GPS provides free navigation and timing signals to worldwide users. Although GPS was originally developed as a military system, during the last decade, the GPS industry has exploded with new applications in transportation, mapping and time synchronization, thus becoming the newest "global utility." GPS is the dominant player on the Global Navigation Satellite System market, which is expected to reach $50B by 2010. Driven by the success of GPS and the huge satellite navigation market potential, the European Union is planning on developing its own satellite system, called Galileo. Galileo will be under civil control and its performance would be similar to modernized GPS. Galileo users will have to pay a fee for Galileo's premium service. The deployment of Galileo raises several military and commercial concerns that could affect U.S. national interests. Before Galileo becomes operational, United States representatives and their European counterparts must resolve many issues such as signal allocation, protection from unauthorized use of the signal, regulatory restrictions and interoperability of the two systems.