John Klein, callsign “Patsy,” is a nonresident senior fellow in the Forward Defense program of the Atlantic Council’s Scowcroft Center for Strategy and Security. Klein is a subject matter expert on space strategy and also instructs space policy and strategy courses at the undergraduate, graduate, and doctorate levels at several universities around Washington, DC. He routinely writes on space strategy, deterrence, and the law of armed conflict. He is the author of the books Space Warfare: Strategy, Principles and Policy (2006), Understanding Space Strategy: The Art of War in Space (2019), and the recently released Fight for the Final Frontier: Irregular Warfare in Space (2023), along with a score of other book chapters and articles.

Klein is also a retired United States Navy commander, receiving his commission through the Navy Reserve Officer Training Corps program at Georgia Tech. He served for twenty-two years as a naval flight officer, primarily flying in the S-3B Viking carrier-based aircraft. Klein supported combat operations in Iraq and Afghanistan. His tours included service as the executive officer of Sea Control Squadron Twenty-Four and the final commanding officer of the Sea Control Weapons School.

Klein holds a master’s degree in aeronautical engineering from the Naval Postgraduate School, a master’s degree in national security and strategic studies from the Naval War College, and a PhD in strategic studies from the University of Reading. Klein is a distinguished graduate of the US Naval Test Pilot School. He has over 2,700 flight hours in twenty-seven different types of aircraft and over six hundred carrier-arrested landings.