Vulcan SRB Anomaly Under Investigation
Author: Jeff Foust
Date Published: October 15, 2024
MILAN — The loss of a solid rocket booster nozzle on the second flight of the Vulcan Centaur had very little effect on the launch itself, but the impact of the incident on the vehicle’s certification by the Space Force remains uncertain.
Incident Overview
On the Cert-2 launch Oct. 4, the nozzle of one of the two SRBs attached to the core stage of Vulcan came off about 35 seconds after liftoff. The incident, called an “observation” by United Launch Alliance (ULA), appeared to have a momentary effect on the vehicle, but it continued its ascent, with the timing of subsequent events falling behind the published timeline by up to 20 seconds.
Performance Impact
In a talk at the International Astronautical Congress here on Oct. 14, Tory Bruno, chief executive of ULA, stated that the incident only caused a small loss of performance. “The net effect of that was less than 2% of the total impulse of the booster,” he said, emphasizing that the motor continued to fire but with reduced efficiency due to the loss of the nozzle.
“We just did not have as much thrust coming out of there as we would like to have.”
The core stage compensated for the loss of performance from the SRB, including steering from the BE-4 engines to deal with the asymmetrical thrust between the two SRBs. “This was less than the liquid propellant reserves in the core stage,” said Bruno. “Vulcan is a beast.”
Engineers' Analysis
Bruno highlighted that engineers are still analyzing data from the flight and comparing them to previous ULA launches, believing that this could be the most accurate injection seen yet.
Investigation into the Nozzle Failure
Despite the successful mission, investigations into why the nozzle came loose are ongoing, as ULA has not observed this kind of incident in 35 firings of the GEM 63 motors and several larger GEM 36XL used on Vulcan.
Future Implications
“I’m pretty confident, having experienced this type of anomaly more than once in my career, that we’ll get to the bottom of this pretty quickly and move on,” Bruno added.
Certification Concerns
What remains uncertain is how this anomaly will affect Vulcan Centaur's certification by the U.S. Space Force. The Cert-2 mission was the second of two necessary launches for certification essential for national security launches. ULA had aimed to complete this certification to perform the first two such launches before year-end.
When asked about changes to the certification schedule, Bruno abstained from speculation, noting that the timeline is under the purview of the Space Force, which has not made public commentary on the matter.
“That will be something we work together on with our Space Force customer,” he noted, adding that Space Force personnel are currently reviewing launch data embedded within ULA teams.
Conclusion
Bruno concluded, “We still had a very, very successful mission, probably one of the most successful missions we’ve flown,” despite the nozzle incident.
References
For more information about Vulcan Centaur and related developments in the space industry, please refer to the following articles:
- Vulcan Competes Second Flight Despite SRB Anomaly
- Launching National Security Operations Using Vulcan Centaur
