October 28, 2016

Oldest GPS navigation satellite to be retired with next launch

File photos of Atlas 5 stacking process. Credit: ULA
File photos of Atlas 5 stacking process. Credit: ULA

CAPE CANAVERAL — A new Global Positioning System craft will ride a United Launch Alliance Atlas 5 rocket into orbit next month to replace a satellite that has operated in space for 25 years.

Stacking of the two-stage launcher for ULA’s first mission of 2016 began this morning at Cape Canaveral’s Vertical Integration Facility next to Complex 41.

Liftoff is planned for Feb. 3 during a morning launch window of 8:47 to 9:05 a.m. EST (1347-1405 GMT). The three-and-a-half hour rocket flight will deliver the payload 11,000 nautical miles above Earth.

The GPS 2A-10 spacecraft, launched aboard Delta 201 in 1990, will fade into retirement with the launch of GPS 2F-12, the latest satellite to join the navigation network.

“(2A-10) will be retired shortly before the launch of 2F-12, as it is nearing the end of its useful life on orbit,” the Air Force tells Spaceflight Now.

For retirement, the satellite will be boosted higher, out of the constellation, into a graveyard orbit and turned off.

The GPS 2F-12 satellite, made by Boeing, is the final craft to be launched from a batch of 12 built to upgrade the constellation and sustain it.

The Block 2F series includes improved accuracy, additional signals, better anti-jamming and longer design lives.

Controllers will put the new addition into Plane F, Slot 1 of the network to take the place of GPS 2R-6 satellite, launched on Delta 281 in 2000. That Lockheed Martin-built satellite has outlived its 7.5-year design life and will shift to an alternate role within the constellation for its remaining years.

“Placing 2F-12 in F-1 enhances the modernized navigation coverage for the GPS constellation,” the Air Force says, adding that the 2R-6 bird “will remain in service, and will be moved to another constellation location where it will enhance GPS legacy coverage and overall constellation robustness.”

The rocket, designated AV-057, will stand 189 feet when fully assembled and fly in the basic, 401-variant that features an RD-180 main engine powering the first stage and an RL10 on the Centaur upper stage. The satellite will be enclosed in a 39-foot-long, 14-foot-diameter aluminum nose cone for atmospheric ascent.

This marks the 72nd GPS satellite launch since 1978, the 17th to use an Atlas rocket and the sixth Block 2F on Atlas.

For ULA, GPS 2F-12 represents the first launch of 15 scheduled this year and the company’s 104th mission overall since formation 109 months ago.

The single biggest customer of ULA launches has been the Global Positioning System, which has used all three rocket families to carry replacement satellites into space 16 times so far, representing a combined mass of 60,000 pounds of payload.

The stacking work for the Atlas began this morning as the bronze-colored, 106.6-foot-long, 12.5-foot-diameter first stage was pulled to the Vertical Integration Facility doorway, erected upright and hoisted inside the building to be put aboard the mobile launcher platform.

Known as the Common Core Booster, the stage produces 860,000 pounds of thrust to lift the rocket off the ground. It burns kerosene fuel and supercold liquid oxygen during the initial minutes of flight.

Upcoming, the barrel-like interstage adapter and Centaur upper stage will be lifted in place. Centaur is 41.5 feet in length, 10 feet in diameter and is fueled by liquid hydrogen and liquid oxygen.

The payload is undergoing its own processing at a nearby Air Force facility. It will be mated to the rocket in late January.

See earlier GPS 2F-12 coverage.

Our Atlas archive.