Vulcan rocket fails in major setback for United Launch Alliance

In a major setback for United Launch Alliance, the company's new heavy-lift Vulcan rocket carrying 40 Amazon Leo internet satellites malfunctioned during the climb to space on Sunday, dooming the payload and throwing a costly wrench into both companies' launch schedules.

"Based on data received by our Launch Director, we confirm that the Vulcan vehicle launched from Space Launch Complex 41 (at the Cape Canaveral Space Force Station) suffered an anomaly 10 minutes into the flight and failed to deliver the Amazon mission to orbit," ULA said in a statement some 50 minutes after liftoff.

"We will work closely with our customer and other appropriate organizations to find the cause, determine the appropriate corrective action and return to flight as quickly as possible."

It was the first outright failure of a United Launch Alliance rocket since the company, a partnership between Boeing and Lockheed Martin, was formed in 2006.

It wasn't immediately known what went wrong, but the Vulcan, the rocket replacing ULA's fleet of Atlas 5 rockets, will face a potentially significant grounding while engineers review telemetry and implement fixes for whatever caused the mishap.

It was only the fifth flight of a Vulcan rocket and the first in nine months as ULA and booster-supplier Northrop Grumman worked to resolve problems with nozzles used by strap-on solid-fuel boosters that marred two earlier flights.

The solids appeared to work normally Sunday, helping boost the rocket out of the dense lower atmosphere before burning out and falling away. The two methane-burning BE-4 engines powering the Vulcan's first stage then continued the climb toward orbit, but they appeared to fire longer than expected based on ULA's pre-launch timeline.

After stage separation, the Vulcan's hydrogen-fueled Centaur upper stage engines took over for a planned 12-minute and 15-second burn. According to ULA's update, something went wrong during that Centaur firing, but no additional details were immediately provided.

Sunday's launch was the first of 38 Vulcan flights purchased by Amazon to launch its Leo satellites, designed to compete head-to-head with Elon Musk's Starlink and other space-based internet providers. ULA has already launched eight Leo flights using Atlas 5 rockets.

Amazon has also booked 24 Leo launches aboard Blue Origin's New Glenn rocket, 24 aboard the European Ariane 6, and 13 aboard SpaceX's Falcon 9. More than 3,300 Leo satellites will be needed to complete the constellation. Sunday's flight would have pushed the total number launched to date to 436.

But it was not to be.

Instead, Amazon Leo will now have to wait on ULA's failure investigation to run its course before trying again with a Vulcan. The company also is waiting for Jeff Bezos-owned Blue Origin to get its New Glenn rocket flying again after a catastrophic on-pad explosion last May.

That failure was caused by a problem with an oxygen valve in one of New Glenn's seven BE-4 first-stage engines. The BE-4, also built by Blue Origin, powers the Vulcan's first stage, but the engines used Sunday had been retrofitted with a fix by Blue Origin engineers.

While the cause of the failure is not yet publicly known, "ULA is committed to full transparency with our customers, and they will have visibility into the investigation process, which utilizes rigorous methodology and corrective action," the company said.

NASA Administrator Jared Isaacman promised assistance if needed.

"Appreciate you quickly keeping the public and your partners informed," Isaacman wrote on the social media platform X. "The team at @NASA is available to assist in all matters related to the investigation and remediation effort. Artemis, Moon Base, and the nation need ULA. We are in your corner and here to help."

The 214-foot-tall Vulcan blasted off from pad 41 at the Cape Canaveral Space Force Station at 12:40 p.m. ET, thundering away on a northeasterly trajectory atop 3.8 million pounds of thrust from six Northrop Grumman strap-on solid-fuel boosters and two methane-burning BE-4s.

A launch attempt Friday was scrubbed after problems knocked out a gaseous nitrogen plant that serves multiple launch providers. Another delay was ordered Saturday because of network problems between the Vulcan and ground systems.

On Sunday, launch controllers called a hold at the T-minus 20-second mark because of an unexplained technical issue with the rocket. Re-targeting the end of the launch window, ULA resolved the problem, and the rocket roared to life and climbed away at the end of the launch window.

It's not yet known if the problem that interrupted the countdown played any role in the subsequent failure.

In any case, the strap-on boosters helped propel the rocket out of the dense lower atmosphere, burning out and falling away about a minute and 40 seconds after liftoff. But the first stage appeared to burn longer than called for in the company's pre-launch timeline.

The first stage also appeared to separate from the rocket's hydrogen-fueled Centaur upper stage later than expected, and telemetry-driven animation showed the Centaur making unusual orientation adjustments early in the burn.

ULA's launch commentators, however, did not mention any problems and the launch broadcast came to an end without confirming whether the Centaur's first planned engine firing went for the full duration.

ULA spent months working to resolve problems with the strap-on booster nozzles that occurred during two earlier flights, one in 2024 and the other this past February. While ULA was free to proceed with commercial flights, the U.S. Space Force put Vulcan launches of national security payloads on hold pending further analysis.

"We've identified three credible causes (of the nozzle issue), and we have taken positive steps to mitigate all of those," ULA CEO Mark Peller told Aviation Week & Space Technology magazine in a pre-flight interview.

The boosters appeared to work normally Sunday.

As for the BE-4 engines, Peller said Blue Origin developed a "design improvement" to resolve the valve issue and carried out a "retrofit" on the engines installed on the Vulcan Leo 1 rocket.

"They were down at our facilities probably a couple months ago and implemented that retrofit kit on the engines on this upcoming mission," Peller said. "And they're working with us to work through our inventory of engines."