Explosive test pushes 1st ULA Vulcan rocket launch to at least June, CEO says

United Launch Alliance was testing last month a version of the Centaur upper stage designed to fly on its new Vulcan rocket, but a hydrogen leak caused a massive fireball, the fallout of which has meant a delay to the rocket’s first launch from Cape Canaveral, according to ULA President and CEO Tory Bruno.

The hardware for that first launch, including its Vulcan first stage and Centaur upper stage, is safe in Florida. The primary payload for the mission, which is dubbed Cert-1, is commercial company Astrobotic’s Peregrine lunar lander, which aims to be the first of NASA’s Commercial Lunar Payload Services missions to fly.

ULA had been targeting May 4 for launch, already a delay from initial plans to launch this year after having to work through issues on one of the two BE-4 engines provided by Blue Origin that power Vulcan.

The test of this separate Centaur test article, though, and the ongoing investigation as to why it caused a massive fireball and damage to the test stand has prompted Bruno to post on Twitter that Cert-1 won’t fly until June or July.

Bruno has been transparent about the incident that occurred on March 29 at the company’s test stand at NASA’s Marshall Space Flight Center in Huntsville, Alabama, posting the same day that “the hardware experienced an anomaly.”

Two weeks later, Bruno posted a video of the explosion taken from a nearby test stand being refurbished by Blue Origin. Bruno said a hydrogen leak either caused by the ground systems leading into the stand or by the upper stage test article within the stand was the reason behind the fireball.

He said the leaked hydrogen accumulated under the rig “until it found an ignition source, caught fire, burned very quickly and ruptured” the forward dome, igniting the liquid hydrogen. “Fast fire, not (mass) detonation. Less damaging.”

Bruno avoided the word “explosion” stating on Twitter that “this was a deflagration (fire) not a detonation, which are technical, but meaningful, distinctions” later posting, “a detonation is massively more destructive, so it’s an important difference.”

Damage in the end was minimal, Bruno said.

“Structure is pretty stout. Obviously, the instrumentation was damaged and the many load actuators and external plumbing attached to the balloon tanks came loose,” he said initially. “Most of what you’re seeing is insulation and smaller bits from the test rig. One piece of the hydrogen tank’s dome, about a foot square, ended up a few feet away. The test article is still inside the rig and largely intact, which will significantly help with the investigation.”

“Just a scratch,” jibed Elon Musk in one exchange.

The damage to the stand, though, delayed team access to the Centaur test article until April 14 with Bruno noting earlier this week that “the investigation will pick up speed now.”

One week since gaining access, ULA has yet to reveal the source of the hydrogen leak.

The test itself was described as “extreme structural load testing of various worst possible conditions,” and the Centaur had already endured 14 similar tests before this incident. Initially, Bruno wasn’t sure if it would delay the Cert-1 mission.

“We’ll see. This test was a pretty extreme scenario,” he said noting they were proceeding with a wet dress rehearsal and flight readiness firing this month.

Vulcan Centaur is the next generation of rocket to replace both ULA’s Atlas and Delta IV rockets. The delivery of the BE-4 engines had been one of the main factors in the continuing delays behind the inaugural Vulcan launch with ULA only getting their hands on them last fall. Vulcan has been in the works since 2014 and had been touting a summer 2022 launch early last year.

It’s tapped for at least five launches from the Space Coast this year. Cert-1 will also fly the first two experimental satellites for Amazon’s Project Kuiper. Jeff Bezos’ planned internet satellite constellation that looks to compete with SpaceX’s Starlink. Amazon has already booked 47 more launches on both ULA’s Vulcan and remaining Atlas V rockets in the next five years.

Bruno said there are 19 Atlas rockets left and five Vulcan rockets currently in various forms of production beyond the Cert-1 hardware. It also has two remaining Delta IV Heavy rockets.

Despite the repeated delays, Bruno said the company won’t rush without knowing it’s safe.

“This is is why we thoroughly and rigorously exercise every possible condition on the ground before flight. Investigation is underway. Vulcan will fly when complete,” Bruno said.

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