Todd Harrison, director of defense budget analysis and the aerospace security project, and senior fellow in the international security program at the Center for Strategic and International Studies, left, leads a discussion with NASA Administrator Jim Bridenstine, right, during an event celebrating NASA's 60th anniversary at the Center for Strategic and International Studies on Monday, July 23, 2018 in Washington. Bridenstine, and former NASA Administrators Sean O'Keefe and Charles Bolden answered questions about the past and future of the agency. (Photo Credit: NASA/Joel Kowsky)