This is a Sources Sought notice to identify launch service providers capable of meeting an emergent requirement for up to 25 high-value National Security Space missions. The missions are planned for procurement across Fiscal Years 2027 (6 missions), 2028 (9 missions), and 2029 (10 missions). The work requires launching payloads to highly stressing orbits, including direct insertion to GEO and MEO, and performing multi-manifest launches. The Government intends to procure these missions from the two currently NSSL Phase 3 Lane 2-certified providers but is seeking capability statements from other potential sources. Respondents must demonstrate verifiable evidence of technical capability, launch vehicle readiness, and a plan for NSSL certification.