On October 4, 1957, the Soviet Union launched Sputnik 1, the first human-made object to orbit the Earth. Six decades later, space-faring nations face a much different space environment, one that's more diverse, disruptive, disordered, and dangerous. Today's space domain presents a number of asymmetries that differ from other domains, creating a deterrence environment with unique policy implications. Escalation and Deterrence in the Second Space Age, a report from the CSIS Aerospace Security Project, discusses the evolution of space as a contested domain, the changing threats to U.S. space systems, deterrence theory and its applications to the space domain, and findings from a space crisis exercise administered by CSIS in late 2016.

Todd Harrison is the director of Defense Budget Analysis and the director of the Aerospace Security Project at the Center for Strategic and International Studies (CSIS) in Washington, D.C.