Context and Chronology

A Vulcan Centaur flight in mid‑February experienced a visible nozzle breach on one of its four GEM 63XL solid strap‑on motors roughly 20 seconds after liftoff, producing a lateral flame plume and a short‑lived roll. Flight controllers reported the roll abated after booster jettison; the twin BE‑4 core engines and the upper stage reportedly sustained commanded performance and completed a multi‑burn profile toward the intended high‑altitude regime. Mission managers said the primary surveillance spacecraft and ESPAStar‑hosted secondary payloads were healthy following separation, and operational telemetry indicated the vehicle fulfilled its delivery objectives before classified second‑stage burns continued under standard protocol.

Despite mission success, the US Space Force placed a hold on Vulcan missions tied to the vehicle while investigators trace the subsystem fault. The pause reflects concern that the observed nozzle breach echoes a nozzle failure detected on an earlier Vulcan certification flight; engineers are comparing telemetry, manufacturing records and thermal‑protection data from both events to determine whether the anomaly is isolated or symptomatic of a broader manufacturing or design issue.

Potential failure modes under review include localized erosion or structural compromise at the nozzle/throat region, thermal‑protection breakdown, or staging/environmental interactions that produce asymmetric plume forces. ULA, suppliers and government stakeholders — including the Space Force and parties tied to mission hardware — face a range of possible responses from targeted inspections and acceptance‑criteria changes to design or process modifications depending on the root cause findings.

Operationally, the hold removes a launch option from national planners and compresses remaining providers’ manifests, raising immediate scheduling pressure, rebaseline requirements for contractors supporting national‑security payloads, and potential insurance and procurement consequences. Although ULA emphasized that this flight delivered its payloads intact, recurring strap‑on anomalies would undermine the reliability premium the joint venture has claimed and could prompt customers and regulators to demand demonstrable corrective steps before restoring sensitive manifests to the vehicle.

Near‑term outcomes to watch include whether the investigation requires retrieval and forensic examination of hardware, the scope of inspections across the GEM 63XL fleet, any acceptance or manufacturing changes ordered by stakeholders, and whether the Space Force reallocates imminent payloads to alternative providers. Those decisions will shape manifest adjustments, insurance recalibrations and longer‑term procurement conversations about industrial base resilience and competitive capacity for defense launches.