ULA's Vulcan Centaur expected to launch in late 2023

United Launch Alliance's Vulcan Centaur rocket is expected to lift off late this year, said ULA CEO Salvatore Bruno, after an explosion delayed the first launch of the rocket scheduled in May.

“Exquisite technology but not an exquisite root cause,” Bruno said at the Aspen Security Forum yesterday.

In April, the company conducted structural qualification testing at the Marshall Space Flight Center, where the top structure of the rocket caught fire.

“This was the very last test I needed to do before flying the rocket that was sitting down on the pad at Cape Canaveral,” Bruno continued.

Bruno explained a stainless-steel tank, measuring 40 feet by 18 feet at the top of the structure, was “paper thin” -- which can lose its shape if not pressurized -- leaked hydrogen leading to an explosion.

Every kilogram added to the vehicle is another kilogram of payload launched into high orbit, according to Bruno.

“There was a local stress riser that missed the first analysis, it leaked, hydrogen got out and hydrogen will always find an ignition source and it caught fire,” he said.

To fix the structural complication, Bruno said the company plans to increase the thickness and weld a plate over the new forward dome and is looking to complete the final testing before the rocket is launched.