Lockheed Martin’s [LMT] Global Positioning System (GPS) III satellite prototype communicated with Raytheon’s [RTN] GPS Next-Generation Operational Control System (OCX) for the first time in August during a series of pre-flight tests, according to a Lockheed Martin statement.
During compatibility and integration tests, Lockheed Martin’s GPS III prototype, formally known as the Non-flight Satellite Testbed (GNST), received commands from the Launch and Checkout Capability (LCC) node at Lockheed Martin’s Newtown, Pa., facility via the OCX servers at Raytheon’s Aurora, Colo., facility before returning satellite telemetry to the control station.
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| Lockheed Martin’s GPS III Non-Flight Satellite Testbed (GNST). Photo: Lockheed Martin. |
This milestone sequence proved the GNST could connect with, and receive, commands from Raytheon’s Launch and Checkout System, part of the OCX that supports the satellite and mitigates risks prior to launch. The GNST is a fully-functioning, full-sized and non-flying GPS III satellite, which is the Air Force’s next-generation position, navigation and timing (PNT) satellite constellation.
Lockheed Martin spokesman Chip Eschenfelder said yesterday the company expects the GNST to finish dry-running launch base space vehicle processing activities, pre-launch testing and other operational objectives by the end of October. The GNST is residing at Cape Canaveral Air Force Station, Fla., in preparation for the 2015 launch of the first GPS III satellite.
Eschenfelder said the GNST will eventually return to Lockheed Martin’s GPS III manufacturing facility outside Denver, where it will continue to serve as a test-bed for future GPS III design modifications, like the addition of a search and rescue satellite payload and a laser retroreflector array. The company and the Air Force agreed in April to add these modifications to GPS III space vehicles 9 and beyond. The Air Force plans to purchase up to 32 GPS III satellites.
The GNST in mid-May successfully completed thermal vacuum chamber trail blazing, which demonstrated facility, mechanical and electrical ground equipment integration, as well as a series of vehicle integration test procedures. The GNST also completed passive intermodulation and electromagnetic compatibility testing in late April, which assures that multiple high-powered signals generated from the satellite’s navigation downlink transmissions do not interfere with each other or themselves. Lockheed Martin had also tested deployment of the GNST’s solar arrays and secondary payload antenna, as well as some final testing of some software scripts (Defense Daily, July 15).
Air Force Space Command (AFSPC) chief Gen. William Shelton said last week the service believed the GPS III program was still on decent footing despite some concerns. The GPS III navigation payload, developed by Exelis [XLS], had run into some snags, halting delivery. But Exelis said Tuesday its work developing the navigation payload had resolved “most issues,” including ensuring adequate signal isolation, or no “crosstalk,” with the mission data unit. Exelis still expects delivery of the navigation payload to Lockheed Martin by early 2014 (Defense Daily, Sept. 25).
Lockheed Martin is currently under contract for production of the first four GPS III satellites and has received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites. GPS III is an Air Force program that will replace aging GPS satellites in orbit, improving capability to meet the evolving demands of military, commercial and civilian users.