SBIRS GEO 5 missile defense satellite launched for US Space Force

The Atlas 5 “421” with SBIRS GEO 5 takes to the skies at Space Launch Complex 41. Credit: Theresa Cross/Spaceflight Insider
A United Launch Alliance Atlas 5 rocket lifted off from Cape Canaveral Space Force Station in Florida to send the SBIRS GEO 5 satellite into space for U.S. Space Force and Missile Systems Center.
Liftoff took place at 1:31 p.m. EDT (17:31 UTC) May 18, 2021, at Space Launch Complex 41. It was the first Atlas 5 launch of the year and it flew in a “421” configuration, meaning it had a 4-meter payload fairing, two strap-on AJ-60A solid rocket boosters and a single-engine Centaur upper stage.

The SBIRS GEO 5 mission launches toward space on May 18, 2021. Credit: Theresa Cross/Spaceflight Insider
Overall, this Atlas 5 rocket was 194 feet (59.1 meters) tall with an “extra extended payload fairing. The first stage was powered by an RD-180 engine while the upper stage engine an RL10.
This was the second launch attempt for this mission as the first on May 17 was ultimately scrubbed because of a faulty temperature sensor on ground-side equipment, according to ULA CEO Tory Bruno.
“Bad sensor prevented us from confirming the [liquid oxygen] chill,” Bruno tweeted. “Was actually fine. Ran out of time before we sufficiently understood it.”
For today’s launch, the weather was almost as good as the previous attempt with Space Launch Delta 45 predicting an 80% chance of acceptable conditions at liftoff. The primary concerns were cumulus clouds.
The first stage burned for just over 4 minutes before separating. The Centaur upper stage then burned for an additional 11 minutes before entering an initial orbit. During that burn, some 4.5 minutes into flight, the payload fairing separated to expose the SBIRS spacecraft.
During this initial coast phase, two secondary payloads were deployed via the aft end of the Centaur upper stage.

Credit: Theresa Cross/Spaceflight Insider
Called EZ-3 and EZ-4, these flight systems are expected to support the deployment of Technology Demonstration Orbiter 3 and Technology Demonstration Orbiter 4, these 12U CubeSats are designed to test technologies on orbit. According to ULA, these microsatellites were sponsored by the United States Air Force Academy.
About 31 minutes after liftoff, a second Centaur upper stage burn, lasting some 3.5 minutes, occurred to put SBIRS GEO 5 into its planned deployment orbit. The spacecraft separated from the upper stage 8 minutes later.
SBIRS GEO 5, which stands for Space Based Infrared System Geosynchronous Earth Orbit Flight 5, is part of a constellation of GEO satellites and HEO (highly elliptical orbit) payloads that consistently tracks for missile warnings, missile defense, battle-space awareness, intelligence, as well as providing consistent infrared surveillance and ground control systems needed to manage all the data.
To date, ULA has launched all SBIRS GEO satellites and is expected to continue a sixth satellite next year, completing the constellation built by Lockheed Martin.
Today, ULA continues its 100% mission success rate with this, its 144th launch. This is also the 87th launch of the Atlas 5 rocket, the 72nd to launch from Space Launch Complex 41 on Florida’s Space Coast.
Video courtesy of ULA
Theresa Cross
Theresa Cross grew up on the Space Coast. It’s only natural that she would develop a passion for anything “Space” and its exploration. During these formative years, she also discovered that she possessed a talent and love for defining the unique quirks and intricacies that exist in mankind, nature, and machines. Hailing from a family of photographers—including her father and her son, Theresa herself started documenting her world through pictures at a very early age. As an adult, she now exhibits an innate photographic ability to combine what appeals to her heart and her love of technology to deliver a diversified approach to her work and artistic presentations. Theresa has a background in water chemistry, fluid dynamics, and industrial utility.