National Security Space Launch

National Security Space Launch (NSSL) is a program of the United States Space Force (USSF) intended to assure access to space for United States Department of Defense and other United States government payloads. The program is managed by the Assured Access to Space Directorate (SSC/AA) of the Space Force's Space Systems Command (SSC), in partnership with the National Reconnaissance Office. Started in 1994 as the Evolved Expendable Launch Vehicle (EELV) launch system program, the initial program goal was to make government space launches more affordable and reliable, leading to the development of the Boeing Delta IV and Lockheed Martin Atlas V EELV families. These remained the primary launch vehicles for U.S. military satellites, and were later joined by the Falcon 9 developed by SpaceX. On 1 March 2019, the program name was changed from EELV to National Security Space Launch (NSSL) to better reflect the growing commercial launch market and the changing nature of launch contracts, including the potential for reusable launch vehicles. The NSSL program launches the nation's most valuable military satellites; contracts to launch lower value payloads, such as those of the Space Test Program, are awarded using different methodologies.