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First GPS III launch delayed for rocket issues

December 19, 2018  - By

The scheduled launch of the first GPS III satellite on December 18 was scrubbed, reportedly due to first stage liquid oxygen thermal limit constraints aboard the SpaceX Falcon 9 Block 5 launch vehicle’s first stage reaching safety limits. A second attempt on December 19 was later ruled out due to ongoing evaluations into the sensor issue.

The launch window may open again on Dec. 20.

This was to have been the first GPS launch aboard a SpaceX rocket, as well as the first SpaceX contracted U.S. National Security mission.

A Falcon 9 rocket awaits launch. (Photo: SpaceX)

A Falcon 9 rocket awaits launch. (Photo: SpaceX)

The first GPS III satellite was originally scheduled to ride aboard a United Launch Alliance (ULA) Delta IV M+ rocket. ULA and/or its prime partners, Lockheed-Martin and Boeing, have conducted every GPS satellite launch since the start of the program. However, due to an assortment of issues variously involving delayed technology development and lawsuits regarding competitive bidding, the Air Force re-opened bidding for the contract as part of its Evolved Expendable Launch Vehicle (EELV) program — “evolved” signifying that the rocket can be recovered and reused.

Recycling Rockets. ULA did not bid on the re-opened contract, citing concerns over the selection process and potential risks with the anticipated lower launch cost. In 2016, the Air Force selected SpaceX to take over most GPS III launches.

SpaceX’s Falcon 9 for this launch will use a new first stage core, the B1054. Although it has re-use capability, it will fly in an expendable configuration this time, with no landing legs and no grid fins. It will be disposed of into the Atlantic Ocean after separation from the second stage.

In other missions, after the satellite-bearing stage separates from the rest of the rocket, the remaining core launcher fires additional fuel to return intact to land or to sea aboard an Autonomous Spaceport Drone Ship (ASDS), a converted barge awaiting in the Atlantic or Pacific Ocean.

New Generation of GPS.  As attentive readers already know, GPS III SV01 is the first of an entirely new design of GPS satellite that will help the Air Force modernize today’s GPS constellation with new technology and advanced capabilities.

GPS III has three times better accuracy and up to eight times improved anti-jamming capabilities. Spacecraft life will extend to 15 years, 25 percent longer than any of the GPS satellites on-orbit today. GPS III’s new L1C civil signal also will make it the first GPS satellite broadcasting a compatible signal with other international global navigation satellite systems, like Galileo, improving connectivity for civilian users.

Lockheed Martin developed GPS III and manufactured GPS III SV01 at its GPS III Processing Facility near Denver. In September 2017, the Air Force declared the satellite “Available for Launch” (AFL) and had the company place it into storage. In 2018, the Air Force called up the satellite for launch and Lockheed Martin delivered it to Florida on Aug. 20. The Air Force nicknamed the satellite “Vespucci” after Italian explorer, navigator and cartographer Amerigo Vespucci.

GPS III SV01 is the first of 10 GPS III satellites originally ordered by the Air Force. GPS III SV03-08 are now in various stages of assembly and test. In August, the Air Force declared the second GPS III AFL and in November called GPS III SV02 up for 2019 launch.

About the Author: Alan Cameron

Alan Cameron is the former editor-at-large of GPS World magazine.