Vulcan Centaur avoids FAA scrutiny after losing solid rocket booster nozzle

An unusual event occurred during United Launch Alliance's (ULA) second launch of the Vulcan Centaur at the end of last week. One of the twin Solid Rocket Boosters (SRBs) lost its nozzle, but the vehicle still made it into space as planned.

Officially, this launch of the Vulcan Centaur – the second of two tests required to certify it to carry national security payloads for US Space Force – was a success. However, a look at the launch footage shows the nozzle of one of the SRBs falling away during the flight around 35 seconds after liftoff.

ULA boss Tory Bruno shared a plot showing that despite the anomaly, the Vulcan Centaur still managed to achieve a trajectory bullseye. That said, the nozzle flying off is cause for concern, and if there had been a burn-through of another part of the booster, it could have exploded.

As for the trajectory of the nozzle as it departed the rocket, Bruno quipped: "Down."

Thrust vectoring was critical as the Vulcan Centaur had to compensate for the imbalance that was created when the part detached from the SRB. The result was that the ultimate trajectory of the Vulcan was not precisely what was planned, but impressively it still sent the payload to the required destination. According to Bruno, the BE-4 engines supplied by Jeff Bezos's Blue Origin performed nominally.

Bruno sought to play down the incident, noting: "Because this was compensated for within reserves, this anomaly was 'invisible' to the rocket," even though it was more than visible to observers on the ground, who saw "fireworks" as the part fell off.

Youtube Video

Relevant bit is at 1:50.26

The fact that the Vulcan Centaur still achieved a bullseye is a testament to the engineering skills of the ULA team.

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This was the second certification launch for the Vulcan Centaur and an unplanned demonstration of the rocket's ability to handle an off-nominal situation. Considering the problems SpaceX's Falcon 9 has experienced over recent months, The Register contacted the US Federal Aviation Administration (FAA) to see if it believed the issue merited an investigation.

The aviation watchdog told us: "The FAA assessed the operation and determined no investigation is warranted at this time."

SpaceX fans might feel a little aggrieved at the ruling. The company's Falcon 9 was subjected to repeated groundings over the past months. The most recent, which involved the upper stage of the Falcon 9 used to launch the Crew-9 being disposed of outside of the targeted area, requires an FAA investigation.

However, the authority has given SpaceX a green light to launch ESA's Hera mission. In this case, the upper stage will not be reentering the Earth's atmosphere as it will be used to send the probe on to its destination: the asteroid Didymos and its moon Dimorphos.

The FAA told us: "The SpaceX Falcon 9 vehicle is authorized to return to flight only for the planned Hera mission scheduled to launch on Oct. 7 from Cape Canaveral Space Force Station in Florida. The FAA has determined that the absence of a second stage reentry for this mission adequately mitigates the primary risk to the public in the event of a reoccurrence of the mishap experienced with the Crew-9 mission.

"Safety will drive the timeline for the FAA to complete its review of SpaceX's Crew-9 mishap investigation report and when the agency will authorize Falcon 9 to return to regular operations." ®