The USSR launches Sputnik, the first artificial terrestrial satellite. In the late 1960s, the United States military was desperately afraid of a nuclear attack from the Soviet Union. The United States created the Advanced Research Projects Agency (ARPA) within the Department of Defense to establish a bomb-proof network to connect military bases. The ARPANET physical network was created in 1969 to allow universities and research organizations to freely exchange information. The first two nodes that formed the ARPANET were UCLA and the Stanford Research Institute, shortly after the University of Utah was added to the ARPANET. The Network Control Protocol (NCP) was initially used as the ARPANET protocol starting in 1970. By 1971, a total of 23 nodes were created. hosts across 15 locations were connected to the ARPANET. The following year, the first international connections took place, linking University College London (UK) and the Royal Radar establishment (Norway) to the ARPANET. The way ARPANET was set up is such that if one of the network's links were disrupted by an enemy attack, the traffic there could be automatically redirected to other links. Fortunately, the Net has rarely been attacked by the enemy. In the 1970s, ARPA also sponsored new research into applications of packet switching technologies. This included the extension of packet switching to ships at sea and land mobile units and the use of radio for packet switching. Ethernet was created during research into the use of radio for packet switching, and it was discovered that coaxial cable could support the movement of data at extremely fast speeds. The development of Ethernet was crucial to the growth of local computer networks. The success of ARPANET has made it difficult to manage, especially with the large and growing number of university sites. It was therefore divided into two parts. The two sides consisted of MILNET, which owned the military sites, and the new, smaller ARPANET, which owned the non-military sites. By January 1, 1983, every machine connected to ARPANET had to use TCP/IP. TCP/IP became the primary Internet protocol and completely replaced NCP (old ARPANET language). Thanks to TCP/IP, MILNET and ARPANET remained connected through a technical scheme called IP (Internet Protocol); which allows traffic to be routed from one network to another if necessary. All networks connected to the Internet speak IP, so they can all exchange messages. Although there were only two networks at the time, IP was designed to enable tens of thousands of networks. An unusual fact about IPdesign is that every computer on an IP network is just as good as any other.