WASHINGTON โ€” As expected, the U.S. Air Force awarded Lockheed Martin Space Systems of Denver a contract modification worth $246 million for production of the seventh and eighth satellites in the next-generation GPS 3 positioning, navigation and timing constellation, the Pentagon announced March 31.

Work on the seventh and eighth GPS 3 satellites is expected to be completed in April 2018 and October 2018, respectively, the announcement said. In February, the Defense Department announced it was awarding Lockheed Martin $14 million to order long-lead components for the spacecraft.

In an interview with SpaceNews in March, Mark Valerio, vice president of Lockheed Martinโ€™s military space business, said the contracts were negotiated using a structure known as cost-plus, incentive fee, in which most of the program risk is assumed by the government. Beginning with the ninth satellite, Lockheed Martin expects to operate under a fixed-price contract, he said.

The GPS 3 satellites are designed to provide more accurate navigation signals that are also more resistant to both intentional and unintentional interference than earlier-generation craft. The first GPS 3 satellite has an expected launch readiness date of April 2016, two years later than originally planned, due in part to a number of issues including difficulties by subcontractor Exelis of McLean, Va., in developing the main payload.

As of late last year, the estimated cost of the GPS 3 space segment through the first eight satellites was $4.4 billion, including nearly $2.8 billion for development and $1.6 billion for procurement, according to a newly released U.S. Government Accountability Office report on military acquisition programs. That translates into an average amortized cost of $547 million per satellite, a 5.6 percent increase from 2008 estimates, the report said.

Although the delays better align the GPS 3 satellite schedule with that of its associated ground system, or Operational Control Segment (OCX), synchronizing the two efforts remains a risk area, the GAO said. โ€œGPS 3 satellites cannot be integrated into the constellation or be considered operational until OCX Block 1 is delivered, which is planned for October 2016,โ€ the GAO said.

Meanwhile, the Air Force is slowing down the procurement of GPS 3 satellites beginning in the 2015 budget year, primarily because earlier-generation GPS satellites are lasting longer in orbit than expected. Previously the service expected to buy two satellites next year; now it plans to buy just one, a change that service officials acknowledge will drive up the per-satellite cost. 

Nonetheless, Gen. William Shelton, commander of Air Force Space Command, told SpaceNews April 3 the service is considering buying more than two GPS 3 satellites at a time. 

โ€œThe real question for me is procurement strategy,โ€ he said in January. โ€œHow are we going to go after buying these things in the cheapest way possible. Block buys? Multiyear procurements?โ€

Valerio added that larger blocks would create greater efficiencies.

โ€œItโ€™s inefficient to buy them two at a time. One at a timeโ€™s really bad,โ€ Valerio said. โ€œOur biggest lever to reduce costs is quantity. I donโ€™t know what theyโ€™re going to do next. Theyโ€™re looking at their out-year funding profile, then they compare back to the constellation, and whatโ€™s the best way for them to buy?โ€

Follow Warren on Twitter: @Ferster_SN

Follow Mike on Twitter: @Gruss_SN

Mike Gruss is SpaceNews' chief content and strategy officer. He brings a wealth of expertise in strategic content, audience engagement, and media innovation, honed through leadership roles at Sightline Media Group, where most recently he was editor-in-chief...