United Launch Alliance completed its final Atlas V rocket launch in a 551 configuration early July 2, sending 29 Amazon Leo broadband satellites from Cape Canaveral Space Force Station. The Atlas V rocket launch lifted off from Space Launch Complex 41 at 12:30:15 a.m. EDT.
The mission was Amazon Leo’s Atlas 5 Amazon Leo 8 flight, also called Leo Atlas 8 and LA-08. Melissa Wuerl, Amazon Leo’s Director of Launch Systems, said Atlas 5 had launched 224 satellites with a 100 percent success rate across all eight missions.
Melissa Wuerl on Atlas 5
Wuerl said, "Atlas 5 has played a critical role in the early deployment phase for Amazon Leo, launching 224 satellites with a 100 percent success rate across all eight missions, and we’re excited to build on that foundation with ULA as we transition to Vulcan." She added, "With hundreds of flight-ready satellites standing by at the Cape and a new, dedicated vertical integration facility ready to support Leo Vulcan 1 and subsequent missions, we have a clear path to increase launch and deployment cadence, helping us quickly expand network coverage following an initial service rollout later this year."
That puts the July 2 flight inside a larger shift. United Launch Alliance is moving Amazon Leo work to Vulcan, while the remaining Atlas 5 rockets are reserved for Boeing’s CST-100 Starliner spacecraft. The last Atlas 5 flights therefore end one launch path for Amazon Leo even as another remains in use for a separate spacecraft program.
Space Launch Complex 41
The rocket flew on a north-easterly trajectory after leaving the pad. ULA said the 205-foot-tall rocket carried company designation AV-114, and the countdown began at 7:49 a.m. EDT on Wednesday after a launch readiness review on Tuesday.
Weather support was also part of the day’s setup. The 45th Weather Squadron forecast an 85 percent chance for favorable weather during the 29-minute launch window.
Final Atlas 5 551
The 551 configuration refers to the fairing size, the number of solid rocket boosters, and the number of Centaur upper stage engines. Before this flight, there had been 22 Atlas 5 551 launches, and the first one supported NASA’s New Horizon’s mission to Pluto on Jan. 19, 2006.
After Thursday’s launch, six Atlas 5 rockets remained. All six are reserved to fly Boeing’s CST-100 Starliner spacecraft in the N22 configuration, the only Atlas 5 variant with a dual-engine Centaur upper stage.
For Amazon Leo, the immediate gain is another 29 satellites in orbit and a cleaner path to Vulcan for the next phase of deployment. Wuerl’s reference to an initial service rollout later this year gives the mission its practical edge: the network is still building toward coverage, and this flight pushes that buildout one batch closer.
