NASA definitively shuts down Boeing's EUS project, selects ULA rocket for lunar missions

The American space agency NASA has made a radical and final decision to shut down the long-standing, problematic project of the advanced upper stage Exploration Upper Stage (EUS), developed by the Boeing corporation for the flagship lunar rocket Space Launch System (SLS). The information about the definitive termination of work on EUS, based on sources within the agency, was first reported by the Ars Technica portal. This decision officially closes a chapter that for years has been a bottleneck for the entire Artemis lunar program. The Artemis program, officially announced in 2017, is the successor to the legendary Apollo program of the 1960s and 1970s. Its goal is not only to return humans to the Moon but also to establish a sustained presence through the construction of the Gateway orbital station and a surface base, which requires regular, advanced supply and crewed missions. The direct cause of this radical change was the chronic delays and uncontrolled cost growth of the EUS project. This stage was essential for missions Artemis IV and beyond, as it was supposed to provide significantly greater payload capacity and trajectory precision than the currently used interim Interim Cryogenic Propulsion Stage (ICPS). In response, NASA turned to the commercial sector, where proven technologies are already available. As reported by Bloomberg and Reuters agencies, the agency has chosen a solution from the consortium United Launch Alliance (ULA). It involves delivering a modified version of the Vulcan Centaur rocket, which is to serve as the upper stage for heavier variants of the SLS rocket, known as Block 1B. This decision is a significant blow to Boeing, which loses a key contract in a program of immense prestige. At the same time, it is a clear signal that NASA is increasingly relying on commercial providers, such as ULA or SpaceX, to achieve its ambitious exploration goals. The Gizmodo portal emphasizes that this is a "heavy blow" to Boeing's participation in the lunar program. The company, already struggling with problems in other segments of its aerospace business, is losing another prestigious project. Meanwhile, ULA, a joint venture of Boeing and Lockheed Martin, paradoxically benefits from the failure of one of its owners. Its Vulcan Centaur rocket, which recently completed its maiden flight, has proven to be versatile and reliable enough that NASA deemed it a trustworthy solution even for such critical missions as crewed flights to the Moon. This change could accelerate the schedule for the Artemis IV mission, planned for the end of this decade, as the ready-made Vulcan rocket eliminates years of uncertainty associated with EUS development. NASA's decision signifies a fundamental shift in the philosophy of implementing large space programs. Instead of continuing the costly and risky development of its own, dedicated systems, the agency is increasingly turning to ready-made, commercial platforms. This model has already proven successful in supplying the International Space Station and in the program of crewed flights to low Earth orbit. Transferring it to the realm of deep space exploration shows the maturity of the private space sector and the growing trust of the agency in its products. Final confirmation of this decision and details of the new contract with ULA are to be officially announced by NASA in the coming weeks.