Georgia Tech Applied Research Tech Corp., Georgia Tech Research Institute (GTRI), Atlanta, Georgia, is being awarded a $339,000,000 extension to the indefinite delivery/indefinite quantity, cost-plus-fixed-fee contract HQ0854-21-D-0002. The contract ceiling value will increase from $121,000,000 to $460,000,000. The ordering period end date is extended from September 28, 2026, to September 28, 2031. No task orders are being issued at this time and the work will continue to be performed in Atlanta, Georgia. This was previously awarded as a sole source contract to GTRI, a University Affiliated Research Center under the authority of Justification and Approval No: 21-0018. This extension will provide continuity in engineering and technical support in systems engineering, test and evaluation, advanced concepts and technologies, simulation, modeling and operations analyses, readiness assessments, and technical direction across a broad spectrum of ballistic missile defense system technologies in their areas of core competencies including sensors and sensor technology, space sciences, and technology development. The government is awarding this extension with only one source under the authority of 10 U.S. Code 3204(a)(3) as implemented in the Federal Acquisition Regulation 6.302-3(a)(2)(ii). The Missile Defense Agency, Huntsville, Alabama, is the contracting agency.