WASHINGTON — As it prepares to launch its fourth GPS 2F satellite, part of the ongoing modernization of its positioning, navigation and timing constellation, the U.S. Air Force has left open the possibility of truncating its planned procurement of next-generation GPS 3 spacecraft.

Currently the Air Force has eight GPS 3 satellites either fully or partially under contract with Denver-based Lockheed Martin Space Systems, and has signaled its intent to buy another 12 with improved capabilities. But the service has acknowledged the possibility of scrapping the follow-on procurement in favor of a new system. 

During a discussion of the service’s GPS 3 plans at an April 25 hearing of the House Armed Services strategic forces subcommittee, Rep. Doug Lamborn (R-Colo.) asked, “Is it better to continue that as opposed to starting a whole new fourth generation?” 

Gen. William Shelton, commander of Air Force Space Command, said the Air Force has the option to either buy another 12 GPS 3 craft or move on to a new generation of satellites.

Shelton appeared to favor continuing the work on GPS 3, but added that the issue would be studied in the fall. 

He said he was proud of the “very active GPS 3 program we have now.”

The Air Force has requested more than $4.2 billion for the GPS 3 program, and another $1.3 billion for the ground system, for the next five years. The first satellite is well into construction and is expected to be ready for launch in April 2014.

On Jan. 29, Air Force Space and Missile Systems Center (SMC) at Los Angeles Air Force Base issued a notice indicating its intent to award a GPS 3 follow-on production contract, one that would include space vehicles nine through 20. The intent is to award a “sole-source fixed price type contract” to Lockheed Martin, the notice said, adding that an award to another source likely would result in unacceptable delays and duplication of effort. 

Air Force officials are planning for the addition of several new features beginning with the ninth space vehicle, including the ability to launch two satellites on the same rocket, the “sources sought” notice said. 

Lockheed Martin officials have estimated that the dual-launch capability could reduce costs by about $50 million per launch. 

The follow-up vehicles are also expected to include a search-and-rescue payload.

“The purpose of this market research is to determine if other sources exist which possess both the capability and experience to effectively perform the contemplated effort,” the notice said. 

Only one company besides Lockheed Martin has experience building GPS satellites: Boeing Network and Space Systems of Seal Beach, Calif., which is under contract to build 12 GPS 2F satellites.

Paula Shawa, a Boeing spokeswoman, declined to comment on whether the company intends to challenge the Air Force’s current GPS 3 procurement plan.

Keoki Jackson, vice president of Lockheed Martin’s Navigation Systems mission area, said in an email May 8 that the company stands ready to deliver on an affordable GPS 3 program.

“Lockheed Martin fully supports the Air Force’s vision of affordable, high-confidence constellation sustainment coupled with low risk insertion of needed warfighter capabilities through the acquisition of up to 32 GPS 3 satellites. This approach leverages the significant back-to-basics investments made in the development program to avoid the costly missteps and delays of the previous block,” Jackson said.   

Lockheed Martin on April 4 completed a preliminary design review for the ninth GPS 3 satellite that included the dual-launch compatibility, and the ability to accommodate signal upgrades and the search-and-rescue payload, spokesman Chip Eschenfelder said.

Meanwhile, SMC officials are gearing up for a planned May 15 launch of the fourth Boeing-built GPS 2F satellite from Cape Canaveral Air Force Station, Fla. United Launch Alliance of Denver will launch the satellite aboard an Atlas 5 rocket.

The GPS 2F satellites provide better accuracy and more resistance to jamming than the previous generation of GPS satellites, most of which are still in operation.

The upcoming launch is the 66th in the GPS program and will bring the size of the current constellation to 31 satellites, Air Force officials said in a conference call with reporters May 7. 

Air Force officials said a battery charging issue that has affected previously launched GPS 2F satellites would be fixed with a software update.

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...