On March 29, an explosion occurred during the testing of the Centaur V upper stage of United Launch Alliance’s (ULA) new Vulcan rocket at Marshall Space Flight Center in Alabama. No injuries were reported, but the incident raised concerns about the company’s progress toward its debut launch.

The explosion happened when the Centaur upper stage was being pressurized. ULA CEO Tory Bruno promptly acknowledged the anomaly on Twitter, stating that the hardware experienced an issue during the qualification testing. Multiple sources confirmed the occurrence of a large explosion, which resulted in a column of burning hydrogen forming a mushroom cloud.

Blue Origin, which operates cameras at a nearby test stand, captured the event on video. Following the incident, ULA asked Blue Origin to delete the footage, to which they agreed. This accident has raised questions about the potential impact on the timeline of the Vulcan rocket’s debut launch.

ULA has publicly set a May 4 target date for the Vulcan rocket’s debut launch. However, even before the Centaur anomaly, it was reported that this date was likely to be postponed until summer based on internal timelines.

We are proceeding forward to the WDR and FRF this month, but a 4 May launch is unlikely.
— Tory Bruno (@torybruno) April 12, 2023

ULA spokesperson Jessica Rye stated that the company is conducting an investigation and will only proceed with the launch when deemed safe. The effect of the Centaur anomaly on the Vulcan’s schedule remains unclear.

Astrobotic, the primary customer for the Vulcan rocket’s first mission, has been asked by ULA to hold off on shipping its Peregrine lunar lander to the launch site.

ULA’s accident investigation, along with consultations with the US Space Force, will determine the implications of the incident on the Vulcan rocket’s timeline.

ULA is racing against time to complete the development of the Vulcan rocket and fly two certification missions this year, allowing it to begin flying national security payloads for the Space Force.