United Launch Alliance has received a $269 million contract modification to execute production services for the Delta IV Heavy launch vehicle.

Under the contract, the joint venture between Boeing and Lockheed Martin will support launch vehicle configuration for the U.S. Air Force. Work will be performed in various locations including Colorado, Alabama, and Florida. The U.S. Department of Defense expects work to be complete by April 2020.

$85.8 million in funds were provided at the time of the contract award. Space and Missile Systems Center in Los Angeles is listed as the contracting activity.

The Delta IV Heavy is one of five configurations of the Delta IV family of launch vehicles. The heavier variant uses two additional common booster cores, or CBCs, as liquid rocket boosters to supplement the first-stage CBC during launch.

Satellites launched with the vehicles are used to support a variety of missions, including national security, telecommunications, and interplanetary exploration.