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.

The Space Development Agency requested bids on Oct. 6 and responses were due Nov. 9. The agency estimates the satellites will be ready to launch in late 2022. 

The manifest will be divided into two planes of 14 spacecraft each in two circular near-polar orbits at an altitude of 950 kilometers, according to the request for proposals. 

The agency said it would select a provider that offered the “best value” based on several criteria such as price, schedule and past performance.