What is Space Segment

Satellite networks play a vital role in enabling essential critical infrastructure services that include public safety; environmental monitoring; maritime disaster recovery and reconnaissance; electronic surveillance; and intelligence operations for law enforcement, the military, and government agencies (Jamalipour & Tung, 2001). As demonstrated by the events following the terrorist attacks in the U.S. on the Pentagon in Washington, D.C. and the World Trade Center in New York City on September 11, 2001, satellite networks also provide redundant communications services when terrestrial networks are disrupted and/or unavailable. Despite their merits, satellite networks are nonetheless vulnerable to cyber attacks that pose threats to national security and the economy. Satellite networks transport voice, video, images, and data through the air as electromagnetic signals, thereby making these transmissions susceptible to interception. Technical advances enable the interconnectivity of satellite systems to public and private wireless and terrestrial networks including the Internet. These advances, however, amplify the risk of cyber attacks that can compromise critical infrastructure functions dependent on satellite networks in sectors that include information technology (IT) and telecommunications; defense; government; banking and finance; utilities; agriculture; emergency services; public health; and transportation (U.S. Department of Homeland Security (DHS), 2003; U.S. Government Accounting Office (GAO), 2004). As a consequence, satellite networks employ an array of security tools and mechanisms for countering costly and widespread cyber incursions and, thereby, ensuring the continuity of critical infrastructure operations. Those cyber attacks that are politically motivated and specifically designed to disrupt essential services are generally attributed to cyber terrorism. This chapter describes the technical fundamentals of satellite networks; examines security vulnerabilities; and explores initiatives for protecting the integrity of satellite network transmissions and operations from cyber incursions and physical attacks. Standards and protocols that safeguard satellite networks from unauthorized use and intentional disruptions and policies, and legislation that facilitate cyberspace asset protection are described. Capabilities of encryption in supporting secure satellite services and the distinctive attributes of the InterPlanetary Internet (IPN), also called the InterPlanetary Network, are explored.