WASHINGTON — The U.S. Air Force has awarded Lockheed Martin Space Systems of Denver a $200 million contract modification to complete production of the fifth and sixth satellites in the next-generation GPS 3 positioning, navigation and timing system, according to announcements from the Pentagon and the company.

In February, the Air Force awarded Lockheed Martin a contract to order long-lead components for the fifth through eighth satellites in the GPS 3 constellation, the company said in a Dec. 16 press release. Full-scale production funding for the seventh and eighth satellites is expected in 2014, the company said. 

The GPS 3 satellites are expected to be more accurate and less vulnerable to jamming than preceding generations of GPS craft.

Work on the fifth vehicle is expected to be completed in December 2017 and work on the sixth is expected to be completed in June 2018, the Pentagon said in a Dec. 12 announcement.

Construction already is well underway in Denver on the first four GPS 3 satellites, with the first slated to launch in 2015.

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Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...