Again! ULA Vulcan Solid Side Booster Failed during Launch!? Here’s What Exactly Happened…

What a disappointing turn of events. The ULA Vulcan encountered another issue with one of its solid rocket boosters during its most recent flight, a problem that had already appeared on a previous mission. Why does this issue continue to resurface? On that same day, the upgraded Ariane 6 successfully launched its enhanced configuration, marking another important step forward for Europe's heavy lift program. At the same time, NASA carried out a smaller test in preparation for its second wet dress rehearsal attempt, carefully working through the procedures required before moving ahead. Let's take a closer look at all of it in today's episode of Great SpaceX. Recently, at 4.22 AM Eastern on the 12th of February, following a slight delay from the original target time, ULA launched a Vulcan Centaur rocket from SLC-41 at Cape Canaveral Space Force Station. The mission, designated USSF-87, carried a classified payload for the U.S. Space Force to geosynchronous orbit. This marked the fourth flight of the Vulcan rocket and the first time the vehicle flew in its four solid rocket booster configuration, rather than the earlier two booster variant. The liftoff was powerful and visually dramatic. The rocket rose from the pad supported by two BE-4 engines on the core stage and four strap-on solid rocket boosters. The combination produced an immense column of thrust. As is typical with solid propellant boosters, the exhaust plume appeared dense and smoky. The flame was not as transparent or sharply defined as the methane-fueled plumes seen on SpaceX vehicles such as the Falcon 9 or on Blue Origin's New Glenn. Instead, the plume carried the thick signature commonly associated with solid engines. However, roughly 20 seconds after liftoff, observers noticed something unusual. The exhaust from one of the solid boosters appeared significantly brighter than expected. The luminosity increased in a way that stood out clearly against the otherwise steady burn of the other boosters. At this stage, it remains unclear whether the brightness was the result of a temporary increase in chamber pressure, a structural resonance within the nozzle, or possibly the burning of internal material that should not have been exposed to the exhaust flow. Another possibility is that a small leak developed and ignited, intensifying the visible plume. At approximately T plus one minute and seven seconds, sparks became visible. These sparks scattered briefly before fading. The visual evidence strongly suggested that some material had either fractured or burned away from the affected booster. While the event was short in duration, it was unmistakable. Fortunately, the situation did not escalate. The four solid rocket boosters continued operating through their burn phase and separated from the core stage as planned. The core stage, powered by its two BE-4 engines, maintained trajectory control. Although questions remain regarding the precise performance of the affected booster, the overall mission profile was preserved. ULA later confirmed that the Centaur upper stage performed anomaly and delivered the payload to its intended orbit. During the flight, ULA posted an update on X stating, We had an observation early during flight on one of the four solid rocket motors. The team is currently reviewing the data. This brief statement acknowledged the anomaly without offering details. A more comprehensive update followed. Gary Wentz, VP of Atlas and Vulcan Programs at ULA, explained, Early during flight, the team observed a significant performance anomaly on one of the four solid rocket motors. Despite the observation, the Vulcan booster and Centaur performed anomaly and delivered the spacecraft directly to geosynchronous orbit. He further stated that an integrated team composed of U.S. government representatives and contractors would review all technical data and imagery. A recovery effort would be established to collect any debris. The team would conduct a thorough investigation, determine the root cause, and implement corrective actions before the next Vulcan mission. The solid rocket boosters used on Vulcan are manufactured by Northrop Grumman. As of now, NG has not released a separate public statement regarding this anomaly. It's highly likely that their engineers are working closely with ULA to analyze telemetry, inspect manufacturing records, and evaluate potential failure points. The troubling aspect of this event is that it echoes a previous issue. During Vulcan's second mission, commonly referred to as SIRT-2, a minor explosion occurred within one of the solid rocket booster nozzles. A ring component inside the nozzle assembly detached and was expelled. That anomaly caused a measurable performance deviation and induced a temporary tilt in the rocket's flight path. The problem was eventually traced to a manufacturing defect in an internal insulator component within the nozzle. Whether the anomaly on USSF-87 is identical to the SIRT-2 issue remains unknown. It's possible that the root cause is different. However, both incidents center on the solid rocket boosters, and specifically on components exposed to intense thermal and mechanical stress. The nozzle region of a solid rocket motor experiences extreme temperatures and high pressure. Any weakness in materials, bonding agents, or insulation layers can quickly escalate under such conditions. The recurrence of anomalies in this subsystem raises legitimate concerns regarding quality assurance and long-term reliability. While the mission ultimately succeeded, military payloads demand the highest level of confidence. National security missions cannot tolerate repeated uncertainties. The competitive landscape further amplifies the stakes. In Phase 2 of the National Security Space Launch Program, ULA retained a substantial share of the missions. However, SpaceX steadily increased its presence. By Phase 3 of the program, across both procurement lanes, SpaceX secured more missions than ULA. This shift reflects a broader trend in which Falcon 9 and Falcon Heavy have demonstrated consistent flight rates and mission assurance. Meanwhile, Vulcan has experienced a lengthy development timeline. Although the program was initiated years ago, the rocket's inaugural launch did not occur until January of 2024. Since then, only four missions have flown. After the SIRT-2 incident in October of 2024, Vulcan did not return to flight until August of the next year. Each delay compounds scheduling pressure and expands the backlog of assigned missions. ULA is also transitioning away from its legacy Atlas V and Delta IV rockets. As those vehicles retire, Vulcan becomes the company's primary launch system. Any disruption to Vulcan's cadence has direct implications for customers. Upcoming missions include launches of the Dream Chaser spaceplane, multiple Kuiper satellites for Amazon, and additional national security payloads. Each program operates on strict timelines and contractual commitments. The concern is not solely technical. It's strategic. As SpaceX continues to refine Falcon 9 and Heavy operations and advances towards Starship, the competitive gap may widen. Vulcan must achieve not only reliability but also a steady launch tempo to remain viable in this environment. Speaking of Amazon Kuiper's constellation, this topic naturally leads to Ariane 6, a rocket that shares several similarities with Vulcan. On its latest mission, designated VA-267, Arianespace debuted the Ariane 64 configuration for the first time. This variant uses four solid rocket boosters paralleling Vulcan's expanded configuration. The launch occurred from Europe's spaceport in Kourou, French Guiana at 11.45 a.m. Eastern, which corresponded to 1.45 a.m. local time. The rocket carried 32 satellites for Amazon's low-Earth-orbit broadband constellation. All spacecraft were successfully deployed one hour and 54 minutes after liftoff, precisely as planned. The mission marked a significant achievement for Arianespace. Unlike Vulcan's recent flight, Ariane 64 did not exhibit visible anomalies during descent. David Cavaiolos, chief executive officer of Arianespace, described the launch as a major milestone for the company, for Amazon, and for the European space sector. We are so proud to support Amazon Leo with a reliable, high-performance European launch solution as we begin a series of 18 missions enabling the deployment of their constellation. We thank Amazon Leo for their confidence and are proud to support them as a trusted launch partner. The Ariane 6 program has now completed six flights in total. The rocket stands 203 feet tall and represents Europe's next-generation heavy-lift launcher. It debuted with a test flight in July of 2024 and completed four operational missions the following year. Those earlier missions used the Ariane 62 configuration, which featured two solid rocket boosters. The 6-4 variant effectively doubles the payload capacity to low-Earth-orbit, exceeding 20 metric tons. Martin Sion, chief executive officer of Ariane Group, stated that the successful introduction of the 4-booster configuration demonstrated the quality of the industrial teams and their European partners. He also noted that efforts are underway to enhance competitiveness by increasing payload capacity and accelerating production beginning this year. This most recent flight was also the first commercial Ariane 6 mission and the first to employ the extended 20-meter payload fairing. The payload, Amazon's Kuiper satellite, highlights the broader market dynamics. Amazon initially selected three rockets for Kuiper deployments, Vulcan, Ariane 6, and New Glenn. However, delays across all three vehicles forced Amazon to purchase Falcon 9 launches to maintain its deployment schedule. Amazon plans to deploy more than 3,200 satellites in total. To date, only 185 satellites have been launched. Achieving full deployment will require dozens of additional launches, including the 18 assigned to Ariane 6. The schedule ahead remains demanding. Turning to NASA, February 12th also saw activity at LC-39B involving the SLS rocket. NASA conducted a test involving the loading of liquid hydrogen into the core stage. Although the agency did not issue a formal announcement beforehand, the test was understood to be part of preparations for a second wet dress rehearsal. This test focused specifically on verifying repairs made to address hydrogen leaks observed during the previous rehearsal. Liquid hydrogen presents extraordinary engineering challenges. Its molecules are extremely small and can escape through microscopic imperfections in seals or joints. When mixed with air, hydrogen becomes highly explosive. Managing propellants safely requires precise temperature control and robust sealing systems. According to a NASA spokesperson, engineers were testing new seals installed on the launch pad umbilical. The procedure involved flowing liquid hydrogen across the interface and partially filling the core stage tank. The collected data would inform the timeline for the next wet dress rehearsal. During the earlier rehearsal attempt, hydrogen leaks were detected at the base of the rocket where the umbilical connects. The launch team managed the situation by pausing and resuming propellant flow, allowing the seals to warm slightly and reduce leakage. However, a more permanent fix was required before proceeding. The wet dress rehearsal is a critical milestone for Artemis 2, the first crewed mission of the Artemis program. Any issue uncovered during this test can influence the mission schedule. If the upcoming rehearsal proceeds smoothly, it may occur around mid-March. If further leaks are detected, additional repairs could push the timeline into April. And that brings us to the end of today's episode. Thank you so much for tuning in, and as always, this has been Kevin from GreatSpaceX. Until next time, keep looking up!