ULA Vulcan SRB Nozzle Anomaly Observed — Mission Continues

ULA Vulcan SRB Nozzle Anomaly Observed During Latest Launch — Mission Continues

🚀 What Happened

United Launch Alliance's Vulcan rocket lifted off successfully today, but eagle-eyed observers at NASASpaceflight immediately spotted what appeared to be a hardware anomaly on one of the twin Solid Rocket Boosters.

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The anomaly became apparent within seconds of liftoff, with NSF reporting a potential nozzle issue that manifested as an irregular exhaust plume from one of the GEM-63XL solid rocket boosters. Despite the visible irregularity, both SRBs burned through their planned duration and separated nominally.

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📊 Observation Timeline

Event Time	Observation	Status
T+0 seconds	Liftoff confirmed	✅ Nominal
T+few seconds	Potential burn-through detected on one SRB nozzle	⚠️ Anomaly observed
Mid-flight (first stage)	Nozzle component likely separated from affected SRB	⚠️ Hardware loss
SRB separation	Both SRBs separated successfully	✅ Staging achieved
Post-separation	Mission continuing nominally	✅ On trajectory

🔍 The Technical Picture

NASASpaceflight's analysis suggests this follows a familiar pattern for SRB anomalies: an initial burn-through event, followed by potential nozzle component ejection, but with the booster continuing to function through its burn duration.

▶ Watch Anomaly Analysis on X

As NSF noted, "SRBs do cough chunks" — solid rocket boosters have historically exhibited phenomena where insulation or nozzle components can separate during flight. The critical question is whether this represents normal operational variation or a recurring design issue.

Importantly, ULA has not issued any official statement regarding the observation as of this writing, and the launch is continuing as planned. This silence could indicate either that telemetry shows acceptable performance margins, or that the company is awaiting post-flight data review before commenting.

🔭 The BASENOR Take

What makes this significant: The October 2024 anomaly was traced to a manufacturing defect in an internal insulator component. ULA subsequently implemented corrective actions and passed a static-fire test in February 2025, earning Space Force certification for National Security Space Launch missions in March 2025.

If today's observation represents a similar nozzle failure mode, it raises questions about whether the manufacturing corrections fully addressed the root cause, or if there's a broader design sensitivity in the GEM-63XL SRB nozzle assembly.

The vehicle's compensation capability is proven: During the Cert-2 anomaly, Vulcan's guidance system and BE-4 main engines successfully compensated for asymmetric thrust by extending burn time approximately 20 seconds, still achieving nominal orbital insertion. Today's successful staging suggests similar compensation occurred.

Regulatory perspective: The FAA assessed the October 2024 incident and determined no investigation was warranted due to absence of public safety impact. A similar determination is likely for today's event, given the successful mission continuation and lack of debris reports.

📰 Deep Dive: Pattern Recognition in Booster Reliability

The aerospace community has long recognized that solid rocket boosters operate in one of the most demanding thermal and mechanical environments in spaceflight. Unlike liquid engines that can be throttled or shut down, an SRB is essentially a controlled explosion once ignited — making any anomaly both dramatic and difficult to mitigate in real-time.

Vulcan's ability to successfully complete missions despite SRB nozzle anomalies speaks to the robustness of its overall system architecture. The rocket's guidance algorithms and powerful BE-4 engines provide sufficient margin to compensate for single-booster degraded performance. This is by design — any launch vehicle carrying high-value payloads or crew must maintain mission success capability under single-point failure scenarios.

However, robust compensation is not a substitute for root cause elimination. Each SRB anomaly consumes performance margin that might be needed elsewhere in the flight profile. For missions requiring maximum payload capacity or precise orbital insertion, even successfully-compensated anomalies reduce operational flexibility. More critically, pattern repetition suggests that the corrective actions implemented after Cert-2 may not have fully addressed the failure mechanism.

The coming days will be crucial. ULA will analyze high-speed camera footage, booster telemetry, and recovered hardware (if possible) to determine whether today's observation shares characteristics with the October 2024 event. If the failure modes are similar, expect a more comprehensive review of the GEM-63XL production process and possibly hardware redesign. If they're distinct, it could indicate a broader quality control challenge across the SRB supply chain.

For the broader launch industry, this incident underscores the ongoing challenges of solid rocket motor reliability — a technology that predates the Space Age yet continues to evolve. As commercial and government customers increasingly demand rapid launch cadence and high reliability, even visually dramatic but mission-successful anomalies will face heightened scrutiny. The standard is shifting from "did the mission succeed?" to "did every component perform as designed?"