ULA launches the last SBIRS U.S. Space Force missile warning satellite

The SBIRS GEO-6 mission was the sixth and final of the Space Based Infrared System constellation of geosynchronous satellites

WASHINGTON — A United Launch Alliance Atlas 5 rocket carrying a U.S. Space Force missile-warning satellite lifted off Aug. 4 at 6:29 a.m. Eastern from Space Launch Complex-41 at Cape Canaveral Space Force Station, Florida.

The SBIRS GEO-6 mission was the sixth and last of the Space Based Infrared System constellation of geosynchronous satellites equipped with scanning and staring infrared sensors to detect ballistic missile launches anywhere on the globe.

The satellite is being deployed to a customized geosynchronous transfer orbit approximately 22,000 miles above the equator. After separation from the main stage about five minutes after liftoff, the Centaur began the first of three planned engine firings to deliver SBIRS GEO 6 to the intended orbit about two hours and 45 minutes after liftoff.

The vehicle’s first stage was powered by an RD-180 engine and two solid rocket boosters. The Centaur upper stage was powered by an Aerojet Rocketdyne RL10C-1-1 engine. 

The SBIRS satellites are made by Lockheed Martin. The $1 billion GEO-6 is built on the LM 2100 bus and carries a sensor payload developed by Northrop Grumman. The first SBIRS GEO-1 launched in May 2011.

ULA has launched all six satellites of the SBIRS constellation.  The Air Force in 2018 decided to cancel the procurement of the seventh and eighth SBIRS satellites due to concerns that these systems were not resilient to possible attacks by adversaries. The Air Force moved to a new program, the Next Generation Overhead Persistent Infrared. Three Next-Gen OPIR satellites are being built  by Lockheed Martin and the first is scheduled to launch in 2025. 

SBIRS GEO-6 was the 95th mission of the Atlas 5, a workhorse rocket that ULA plans to retire in the near future as it seeks to end its reliance on the Russian RD-180 engine. While it transitions to a new vehicle, Vulcan Centaur, ULA still has 19 remaining missions under contract for the Atlas 5, said Gary Wentz, ULA’s vice president of government and commercial programs. These include two national security launches, seven civil space crew missions and 10 commercial launches.

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