DeciBel Research Inc., Huntsville, Alabama, is being awarded a $40,588,656 extension to indefinite-delivery/indefinite-quantity, cost-plus-award-fee contract HQ0147-19-D-0003. The total value of this contract will increase from $172,576,570 to $213,165,226. No task orders are being issued at this time. The work will continue to be performed in Huntsville, Alabama. This was previously competitively awarded to provide continued support for the development and sustainment of Missile Defense Agency’s (MDA) modeling and simulation truth and elements representations. This extension will allow for the uninterrupted execution of MDA’s Integrated Master Test Plan that includes ground test events, flight test events, and warfighter training and combatant command exercise events. The government is awarding this extension with only one source under the authority of 10 U.S. Code 3204(a)(1) and Federal Acquisition Regulation (FAR) 6.302-1. The ordering period end date is extended from June 13, 2024, to Dec. 13, 2027, and incorporates five options: two 12-month options and three six-month option (six-month option via FAR 52.217-8 if necessary). The Missile Defense Agency, Huntsville, Alabama, is the contracting activity.