Upper Stage Issue Impedes Vulcan Rocket’s First Launch

The highly anticipated debut launch of the Vulcan rocket moved a step closer last week with the successful completion of a critical engine-firing test. However, an unresolved issue with the rocket’s Centaur V upper stage has surfaced, leading to a delay in its launch.

An image of the Centaur V anomaly that occurred on March 29 during testing of Vulcan's upper stage at Marshall Space Flight Center. Credits: unknown — *An image of the Centaur V anomaly that occurred on March 29 during testing of Vulcan’s upper stage at Marshall Space Flight Center. Credits: unknown*

United Launch Alliance’s chief executive, Tory Bruno, took to Twitter to announce the identification of the root cause of the Centaur V upper stage failure that occurred during a test in March. The investigation into the incident has been concluded, marking an important milestone toward resolving the issue.

Root cause found. Working corrective action and retest
— Tory Bruno (@torybruno) June 12, 2023

Uncertain Launch Date Although no specific target launch date has been established in recent updates by Bruno or United Launch Alliance, reliable sources suggest to ArsTechinca that the launch is unlikely to take place before the fourth quarter of this year, due to “additional necessary work”.

Milestone: Flight Readiness Firing

On June 7, United Launch Alliance achieved a significant milestone by conducting a successful hot-fire test of the Vulcan rocket’s first-stage engines. The BE-4 engines, developed by Blue Origin, underwent the ignition sequence and reached the target power level for two seconds before powering down.

The United Launch Alliance (ULA) Vulcan Certification-1 (Cert-1) rocket performs the Flight Readiness Firing FRF) at Space Launch Complex-41 at Cape Canaveral Space Force Station in preparation for the inaugural flight. Close-up view on Vulcan Booster stage's two BE-4 engines firing during the FRF. — *Vulcan’s First stage BE-4 engines firing. Credits: ULA*

The completion of this long-awaited engine firing test addressed what was believed to be the primary concern before the Centaur anomaly occurred. The delivery of the BE-4 engines had experienced delays due to Blue Origin’s development and testing process.

United Launch Alliance issued a statement after the test firing, acknowledging the ongoing review of the test data and simultaneous investigation into the Centaur V test stand anomaly. The company emphasized the importance of testing in their launch vehicle development program, ensuring that they will proceed with a launch plan when they deem it safe.

Centaur Stage Update

Responding to inquiries on Twitter, Tory Bruno confirmed the completion of ULA’s investigation into the Centaur failure. Although the report remains unpublished, it appears that the hydrogen tank failed during a pressure test at the Marshall Space Flight Center in Alabama.

To address the issue, the qualification tank of the Centaur stage will be strengthened, and subsequent pressure testing will occur at Marshall during the summer.

The super thin, high performance steel skin needs to be a little thicker near the top of the dome.
— Tory Bruno (@torybruno) June 13, 2023

Whether modifications are required for the flight version of the Centaur stage, which has already been delivered to the launch site in Cape Canaveral, Florida, remains uncertain. If modifications are necessary, the testing and modification process could extend over a few months.

ULA’s Collaboration with Space Force

Throughout the challenges encountered during Vulcan’s development, United Launch Alliance has maintained a close working relationship with the US Space Force. The Space Force has been the company’s key customer since ULA’s creation nearly two decades ago.

In 2020, the US military awarded United Launch Alliance and SpaceX five-year contracts as part of the “National Security Space Launch Phase 2” program, encompassing approximately 40 missions from fiscal year 2022 to 2028. ULA secured 60 percent of the launches, with SpaceX receiving the remaining 40 percent.

*Vulcan Centaur artist’s rendering. Credits: ULA*

Concerns regarding Vulcan’s readiness have arisen, as it was initially expected to commence launching national security missions in 2022. However, due to the requirement for Vulcan to complete two “certification” flights before being deemed safe for valuable reconnaissance satellites, this schedule has been pushed back to at least 2024.

Space Force Phase 2 Assignments

In a notable announcement last Friday, the Space Systems Command disclosed the assignment of a dozen Phase 2 missions to the two launch providers. United Launch Alliance and SpaceX received an equal share of these launches, deviating from the previously allocated 60-40 split.

Furthermore, a recent report by the US Government Accountability Office (GAO) highlighted that delays in Vulcan’s development were causing military officials working on the Phase 2 launch program to explore alternative options. The report noted that the Phase 2 contract enables the reassignment of missions to the other provider in the event of Vulcan’s unavailability.