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U.S.A.F’s first GPS III satellite connects with OCX system

GPS III satellite undergoing production. Photo Credit: Lockheed Martin

GPS III satellite undergoing production. Photo Credit: Lockheed Martin

The first GPS III spacecraft slated to be sent aloft has had its communications system successfully tested when the Next Generation Operational Control System (OCX) sent commands to a prototype in what was deemed a “validation” of the USAF’s new Global Positioning System (GPS) satellite. In so doing, it has cleared the GPS III satellite for launch.

Produced by Lockheed Martin, the GPS III Space Vehicle 01 (GPS III SV01) successfully conducted Factory Mission Readiness Testing (FMRT) which included the Raytheon-produced OCX system.

“During FMRT, GPS III SV01 received and successfully processed OCX commands that are routinely sent during launch, transfer orbit maneuvers, deployments and payload initialization,” said Mark Stewart, Lockheed Martin’s vice president for Navigation Systems via a release issued by the company. “We thoroughly tested the first GPS III satellite just like we are going to fly it in 2018.”

The FMRT served to confirm that command control between the GPS III spacecraft and the OCX Launch and Checkout System (LCS) would work (the test ran through a simulated launch and orbital insertion sequence).

“This was the first time the launch and checkout system directly interfaced with the GPS III satellite,” said Bill Sullivan, vice president of Raytheon’s GPS OCX program. “We’re making consistent, steady progress, and that’s driving us toward a successful launch next year.”

Throughout the test, signals were sent from OCX LCS software that had been loaded onto Lockheed Martin’s Launch and Check Out Capability node in Denver, Colorado. These commands were then sent to Schriever Air Force Base located in Colorado Springs, Colorado and then uplinked to the GPS III spacecraft. This wasn’t the first time that GPS III and OCX “spoke” with one another (a link check was conducted on Oct. 3, 2017).

As noted, the test helped confirm that the first GPS III satellite is ready for flight as it helped prove that the spacecraft should be able to communicate and take instructions from the ground. 

To conduct this test Lockheed Martin used the GPS III Nonflight Satellite Testbed (GNST) – a full-sized and functional satellite prototype – also connected with and received commands from an earlier version of Raytheon’s OCX LCS software (according to a Lockheed Martin-issued statement).

With this test complete, GPS III SV01 will be shipped to the launch site, Cape Canaveral Air Force Station in Florida in preparation for its ascent to orbit.

If everything goes as it is presently planned, the first launch is slated for May of next year (2018). Each GPS III satellite has a design life of 15 years and is based off of the A2100 bus.

Video courtesy of Lockheed Martin




Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

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