Spaceflight Insider

First GPS III satellite completes thermal vacuum test


An artist’s rendition of the GPS III satellite. Image Credit: Lockheed Martin

Lockheed Martin announced on Feb. 3, 2016 that the first Global Positioning System (GPS) III satellite has completed a system-level thermal vacuum test, validating the design and proving it can operate in the extreme environment of space.

The test—a thermal vacuum (TVAC) test—occurred on Dec. 23 of last year in a special vacuum chamber. The test confirmed that the entire assembled spacecraft could withstand prolonged cycles of simulated space temperature extremes.

“TVAC is the most comprehensive and perceptive test performed at the spacecraft level,” Mark Stewart, vice president of Lockheed Martin’s Navigation Systems mission area, said in a press release.

Technicians and engineers inspected the GPS III SV-01 spacecraft after it completed the system-level Thermal Vacuum test. Photo Credit: Lockheed Martin

Technicians and engineers inspected the GPS III SV-01 spacecraft after it completed the system-level Thermal Vacuum test. Photo Credit: Lockheed Martin

Stewart noted that the successful completion of this test validates the thermal design of the spacecraft while verifying all of the satellite’s components will operate in the environment of space.

This is the latest milestone for the first GPS III satellite, which underwent integration last spring. In the fall, those components underwent acoustic and vibration testing, something critical during the rough ride it will endure as it climbs out of Earth’s gravity well atop its launch vehicle.

Lockheed Martin is contracted for at least eight of the Block III satellites, the first of which is expected to launch sometime in 2017.

The Block III is the next generation of GPS satellites, aimed at replacing the already aging constellation. This modernized spacecraft should improve positioning, navigation and timing services. It is designed to be more secure, accurate, and reliable than the previous blocks. Its positional accuracy will be within one meter.

The GPS III satellites are designed to provide military users with up to eight times the improved anti-jamming capabilities currently available while becoming the first GPS satellite to host a civil L1C signal which will be shared by other international Global Navigation Satellite Systems.

It is expected to have an operational life at least 15 years, more than 25 percent longer than the current Block IIF satellites. The GPS III satellites will operate at an altitude of 12,541 miles (20,183 kilometers) in six orbital planes at 55 degrees inclination.

Lockheed Martin was awarded the contract in 2008 for the design, development, and production of the GPS III Non-Flight Satellite Testbed as well as the first eight spacecraft in this design.

The Block III design uses Lockheed Martin’s A2100 bus structure, which is manufactured by Orbital ATK. Additionally, each satellite will carry eight deployable JIB antennas which were designed and manufactured by Northrop Grumman Astro Aerospace.

“We have a world-class industry team supporting the development and production of GPS III for the Air Force and our nation,” Stewart said. “I thank them for their excellent work and commitment to this program.

Video courtesy of Lockheed Martin


Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity.

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