The United States is more dependent on space than any other state, not only for national security, but for the private sector as well. National secur­ ity space capabilities – precision navigation and timing, battlefield and battlespace characterization, missile warning and defense, weather, com­ munications, intelligence, surveillance, and reconnaissance – enable the United States and its allies to reach out, shape, support, and control events in any part of the globe. Space capabilities are also important enablers for successful 21st century global economies, information transfer, diplomatic communication, and collaboration. Recognizing the importance of protecting satellites as strategic assets, the United States has effectively employed a comprehensive strategy to preserve access to their capabilities since the earliest stages of the space age. Emerging threats posed by new hostile states, non­ state actors, and the environment now serve as a catalyst for reappraisal of the strategy and political, diplomatic, economic, and technical means the United States must employ to protect against and even defeat threats to space assets. As part of this reappraisal in the United States, a 2010 National Space Policy has been proclaimed by the Obama Administration, and a 2011 National Security Space Strategy has been issued by the Secretary of Defense and Director of National Intelligence. Still more can be done; a more well­ rounded space assurance strategy should be adopted, protecting space assets from the space environment and irresponsible actions and actors, and deterring others from interfering with space assets.