A Survey on Network Security issues in Space Internet

Space Internet, which integrates satellite communication networks, aerial networks, terrestrial networks,and marine communication networks, has been an emerging architecture and attracted intensiveresearch interest during the past years. In consideration of its cooperation characteristics ofmulti-layer networks, open communication environment, and time-varying topologies, Space Internetfaces many unprecedented security challenges. We provide a detailed survey of recent researchworks on network security issues in Space Internet in the aspects of security threats and defensecountermeasures. To the best of our knowledge, we are the first to present the state-of-the-art ofsecurity for Space Internet, since existing surveys focused either on a certain segment or on severalsegments of the integrated network. We first briefly introduce the essential background and the viewof the Space Internet, as well as discuss the related security challenges faced by the emerging integratednetwork architecture. Then, we present a comprehensive review of recent research worksconcerning network security issues in Space Internet, which we categorize by different research directions.Finally, several future challenges and the respective open research topics are described.