A United Launch Alliance Atlas 5 551 rocket lifts off from Spaceport 41 at Cape Canaveral Space Force Station on the Leo Atlas 8 mission on July 2, 2026. Image: John Pisani/Spaceflight Now
Update July 2, 1:30 a.m. EDT (05:30 UTC): ULA confirms deployment of 29 Amazon Leo satellites.
United Launch Alliance has closed a major chapter in the company’s history. Thursday morning’s pre-dawn launch from Cape Canaveral Space Force Station in support of the Amazon Leo satellite constellation marked the final flight of an Atlas 5 rocket flying in the 551 configuration.
The rocket carried 29 broadband Internet satellites as part of Amazon’s Atlas 5 Leo 8 mission, which Amazon also called Leo Atlas 8 (LA-08).
Lift-off from Cosmodrome 41 occurred at 04:30:15 Eastern Time (04:30:15 UTC). After leaving the site, the rocket flew along a northeast trajectory.
“Atlas 5 played a critical role in the early deployment of Amazon Leo, launching 224 satellites with 100 percent success on all eight missions, and we are excited to build on that foundation with ULA as we transition to Vulcan,” said Melissa Wuerl, director of launch systems for Amazon Leo, in a statement. “With hundreds of flight-ready satellites stationed 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 increasing launch and deployment frequency, which will help us quickly expand network coverage following the initial rollout of services later this year.”
The 45th Weather Squadron forecasts an 85 percent chance of favorable weather during the 29-minute launch window. Meteorologists are monitoring a slight chance of interference from cumulus clouds.
After completing launch readiness checks on Tuesday, the countdown to launch began at 7:49 a.m. ET (11:49 UTC) on Wednesday. Teams prepared to transport the 205-foot (62.5 m) rocket from the Vertical Integration Facility (VIF-G) to the launch pad.
Sitting on a mobile launch platform (MLP), Atlas 5 flew along railroad tracks about a third of a mile from the launch pad. After the “go to work” signal was received around 10 a.m. ET (14:00 UTC), the 1.9 million lb (862,000 kg) MLP and Atlas 5 rocket began moving.
The MLP was lowered onto the launch pad supports at 11:11 a.m. EDT (15:11 UTC), establishing a “hard descent” status. With the necessary umbilicals attached to the rocket and payload fairing, and the support machines removed, ULA began loading the RP-1 rocket’s booster rocket fuel at approximately 2:30 p.m. Eastern Time (6:30 p.m. UTC), which was completed an hour later.
United Launch Alliance rolled out its latest Atlas 5 551 rocket onto Space Launch Complex 41 and is preparing to launch the Leo Atlas 8 mission at 12:24 pm ET (04:24 UTC) on July 2. Loading of fuel (RP-1) onto the Atlas launch vehicle began at 14:30 Eastern Time (18:30 UTC).
Time lapse:… pic.twitter.com/aHppLTtFn4
— Spaceflight Now (@SpaceflightNow), July 1, 2026
The rocket carries ULA’s designation AV-114 and will be the 110th Atlas 5 rocket launched to date.
Configuration 551 designates the size of the fairing (five meters), the number of solid rocket boosters and the number of Centaur upper stage engines. To date, there have been 22 Atlas 5551 launches, the first of which was launched in support of NASA’s New Horizon mission to Pluto, which launched on January 19, 2006.
After Thursday’s launch, only six Atlas 5 rockets will remain, all designed to fly on Boeing’s CST-100 Starliner spacecraft.
These rockets fly in the N22 configuration and are the only variant of the Atlas 5 rocket with a twin-engine Centaur upper stage. After several problems arose during the 2024 Starliner crew flight test, leading NASA to declare a Type A accident, the launch date of the cargo-only Starliner 1 is in doubt.
A United Launch Alliance Atlas 5 551 rocket lifts off from Spaceport 41 at Cape Canaveral Space Force Station as part of the Leo Atlas 8 mission on July 2, 2026. Image: Adam Bernstein/Spaceflight Now
Move to next chapter
Amazon’s Leo constellation of satellites is being launched into space using a variety of launch providers other than ULA. He flew three missions each with Arianespace and SpaceX, using their Ariane 6 and Falcon 9 rockets, respectively.
The company also acquired 38 launches using ULA’s Vulcan rockets and 27 launches using Blue Origin’s New Glenn rockets. However, both of these launch vehicles remain on the ground as they undergo their own anomaly investigations.
A United Launch Alliance Atlas 5 551 rocket rests on Space Launch Complex 41 at Cape Canaveral Space Force Station prior to the launch of the Leo Atlas 8 (LA-08) mission. Image: John Pisani/Spaceflight Now
Before the launch of Amazon Leo’s latest mission on an Ariane 6 rocket earlier this month, Stephen Metayer, vice president of manufacturing operations for Amazon Leo, said there would be another Ariane 6 launch this year in support of the constellation, but did not specify when that would happen in the next six months.
He said the first flight of Amazon’s Leo Vulcan satellites is expected to take place sometime in the third quarter of 2026. ULA has housed its Vulcan rocket in its new VIF-A hangar and plans to conduct a fueling dress rehearsal after LA-08’s launch.
Once launched, there will be 396 Amazon Leo satellites in low-Earth orbit. The company aims to begin commercial service by the end of the year, but has not indicated how many satellites it will need to begin this initial offering.
The tech giant has attracted a number of enterprise clients, including a recent deal with Hitachi Construction Machinery that was announced on June 24.
“Under this agreement, Hitachi Construction Machinery will deploy portable Amazon Leo antennas on construction sites in the UK and Germany starting in 2026, using satellite communications for critical maintenance workflows including machine health reporting, downloading field service manuals, receiving real-time maintenance alerts and downloading inspection reports,” Hitachi said in a press release.
A United Launch Alliance Atlas 5 551 rocket lifts off from Spaceport 41 at Cape Canaveral Space Force Station on the Leo Atlas 8 mission on July 2, 2026. Image: John Pisani/Spaceflight Now