WASHINGTON — SpaceX has been awarded a $150.4 million contract to launch as many as 28 satellites for the Pentagon’s space agency, the Defense Department announced Dec. 31.

The contract is to launch a mix of small and medium spacecraft of different sizes that the Space Development Agency is acquiring from multiple vendors. That includes 20 data-relay satellites known as the Transport Layer and the other eight are missile-warning satellites known as the Tracking Layer.

SpaceX will launch these satellites from Vandenberg Air Force Base, California.