Atlas V launches the last national security mission.

As the hints of morning rose on the Florida coast on July 30th, the Atlas V 551 rocket was being fuelled for its final mission for the US Space Force. This marked the last of its kind, as the powerful Atlas V variant prepared to carry a secretive payload into space for the last time.

the pre dawn Florida sky on launch day. credit: Greg Scott photography

This mission utilized the Atlas V 551, the most powerful variant in the Atlas lineup. For those unfamiliar with the naming convention, the first digit represents the fairing type, with 5 indicating a 5-meter fairing and 4 indicating a 4-meter fairing. The second digit denotes the number of solid rocket boosters, while the third digit specifies the number of RL10 engines on the Centaur upper stage. This particular launch featured a 5-meter fairing, 5 solid boosters, and a single RL10 engine.

As the countdown progressed, the Florida sun began to rise, casting a warm glow on the frosty Atlas V rocket. At T-0, the rocket’s RD-180 engine and boosters ignited, leaping it off the pad on a pillar of fire. The launch was bittersweet, as it highlighted the approaching end of an era for the Atlas V, with future US Space Force missions set to transition to the newly flight-proven Vulcan rocket, which launched Astrobotic’s Peregrine mission earlier this year.

Atlas V riding a pillar of fire. credit: Greg Scott photography

Despite the shift to the Vulcan rocket, the Atlas V isn't retiring just yet. It remains scheduled for several high-profile missions, including launching Boeing's Strainer spacecraft and Amazon's Project Kuiper satellites. This ensures the Atlas V will continue to make significant contributions to space exploration and technology.

Vulcan rolling towards the pad, preparing for the Cert 1 launch. credit: Brandon J Moser.

As the Atlas V soared into the sky, the sunlight illuminated its exhaust plume, creating the striking “jellyfish effect” often seen during Falcon 9 launches. Midway through its first stage burn, the rocket’s fairing separated, and the official launch stream was cut off at the request of the US Space Force, maintaining the secrecy of the mission. after that, united launch Alliance confirmed that the launch was a total success