Cherokee Nation Strategic Programs, Tulsa, Oklahoma (HDTRA122D0001); Advanced Research Associates Inc., Alexandria, Virginia (HDTRA122D0002); Parsons Government Services International Inc., Centreville, Virginia (HDTRA122D0003); Black & Veatch Special Projects Corp., Overland Park, Kansas (HDTRA122D0004); and Valiant Global Defense Services Inc., San Diego, California (HDTRA122D0005), are each being awarded an indefinite-delivery/indefinite-quantity, multiple award contract for the Assessments, Exercises, and Modeling and Simulation Support (AEMSS). The maximum dollar ceiling including the base period and option period for all five contracts combined is $850,000,000. Work will be performed at various locations throughout the world. Task orders issued may be for a duration of one year past the last ordering date of the contracts. Funding will be obligated for each task order and no funds are obligated on the basic contracts. The contracts were competitively procured via solicitation HDTRA120R0006 and the government received 12 offers. The Defense Threat Reduction Agency, Nuclear Enterprise Contracting Office, Fort Belvoir, Virginia, is the contracting activity.