A Centaur V upper stage explodes during a test at NASA Marshall, delaying Vulcan's first launch

United Launch Alliance/Vulcan Centaur

A Centaur V upper stage built for testing failed explosively on March 29, 2023 during structural qualification at NASA Marshall Space Flight Center in Huntsville, Alabama. A weld crack in the forward dome allowed liquid hydrogen to leak and ignite. ULA reinforced the stage design with additional stainless steel, delaying Vulcan's first flight.

• Test failure on 15th test cycle; weld failure in forward dome where 15 triangular stainless-steel sections converge at top; hydrogen leak ignited mid-test.
• Root cause: laser-weld strength 'less than assessed'; ULA added reinforcement layer, adding 300 lbs for first flight, 150 lbs for future missions.
• Test article destroyed, but not Vulcan's first-flight hardware; design fix required before launch clearance; Vulcan maiden flight subsequently delayed to late 2023.