Full Breakdown
NASA's Artemis Program Restructures with New Upper Stage
3/11/2026, 12:10:17 PM
Overview of the Artemis Program Changes
NASA has announced significant changes to its Artemis program aimed at establishing a long-term human presence on the Moon. On February 27, NASA Administrator Jared Isaacman outlined a new vision that includes updated mission goals for Artemis 3 and subsequent missions, a shorter launch cadence for the Space Launch System (SLS) rocket, and a redesign of the SLS upper stage. The previous plan involved using the Interim Cryogenic Propulsion Stage (ICPS) for Artemis 1 through Artemis 3, followed by the more powerful Exploration Upper Stage (EUS) for Artemis 4 and beyond. However, NASA has opted for a standardized SLS configuration, which will now incorporate the United Launch Alliance's (ULA) Vulcan Centaur V upper stage.
Selection of the Vulcan Centaur V Upper Stage
The decision to replace the existing ICPS with the Vulcan Centaur V was confirmed on March 6, when NASA's procurement filing indicated a sole-source contract for ULA to provide the next-generation upper stages for Artemis 4 and 5. The Centaur V, which has a proven flight record and is powered by two RL10 engines, is designed to meet the performance requirements of the SLS while also adhering to NASA's schedule. This upper stage is notable for holding approximately twice as much fuel as the ICPS and being nearly the same diameter as the Orion crew capsule.
Implications for Future Artemis Missions
The restructuring of the Artemis program has led to a redefined mission timeline. Artemis 2, which is scheduled for a potential launch as early as April 1, will remain unchanged and will carry a crew of four astronauts on a lunar flyby. In contrast, Artemis 3, initially planned as the first lunar landing in 2028, has been shifted to a 2027 test flight involving Orion and one or more lunar landers, including SpaceX's Starship and Blue Origin's Blue Moon. Artemis 4 is now positioned as the first mission with the goal of landing astronauts on the Moon, targeted for 2028, with Artemis 5 potentially following suit in the same year.
Criticism and Concerns
While the changes have been framed as necessary for advancing the Artemis program, some critics have raised concerns regarding the reliance on ULA's Centaur V. The decision to halt the development of the Block 1B and Block 2 versions of the SLS has led to questions about the long-term viability of the SLS as a launch vehicle, especially with the SpaceX Starship expected to eventually take over lunar missions. Critics argue that the delays and technological challenges facing Starship could hinder NASA's ability to meet its lunar exploration goals.
Official Statements
NASA officials have justified the selection of the Centaur V, stating, "ULA’s Centaur (with minor modifications) is the only existing in-space propulsion stage capable of meeting the SLS upper stage design parameters and performance characteristics, while also meeting NASA’s schedule." This statement underscores the urgency of maintaining a viable launch vehicle for upcoming Artemis missions.
Verbatim Quotes
- “ULA’s Centaur (with minor modifications) is the only existing in-space propulsion stage capable of meeting the SLS upper stage design parameters and performance characteristics, while also meeting NASA’s schedule,” — NASA Official
- “With the procurement filing on March 6, NASA secures the SLS as a viable launch vehicle for many more years to come.” — SpaceNews Report
The restructuring of the Artemis program marks a pivotal moment in NASA's lunar exploration efforts, with the Vulcan Centaur V poised to play a crucial role in future missions.
