WASHINGTON — The U.S. Air Force plans to extend a contract with Lockheed Martin Space Systems of Sunnyvale, California, for operation support services on the service’s legacy communication satellites through June 2015, according to a document posted to the Federal Business Opportunities website Nov. 25.

The contract, worth about $49 million, would cover orbital operations of the Milstar constellation, which provides highly secure communications, and the Defense Satellite Communication System (DSCS). Lockheed Martin was the prime contractor on both programs and has held the contract on similar work since 2009. The total value of that contract, with the new extension, is about $458 million, the document said.

In a document explaining its justification for forgoing competition before extending Lockheed’s contract, the Air Force said awarding the work to another company would result in at least $250 million of duplicate costs.

In June 2015, the work is expected to be part of the Air Force’s Combined Orbital Operations Logistics Sustainment, known as COOLS, which will oversee the Milstar, DSCS and Advanced Extremely High Frequency satellites. The Air Force announced in December 2013 it is pursuing a sole-source contract with Lockheed Martin for that work as well.