NASA selects Centaur V as SLS upper stage amid Artemis shakeup

NASA has identified ULA's Centaur V as the next upper stage for the SLS for Artemis IV and V in a sole‑source SAM.gov posting, and the agency has revised Artemis mission roles and timelines including an accelerated schedule for flights after Artemis 2.

NASA has revised the Artemis program and identified a new upper stage for its Space Launch System (SLS) moon missions. On Feb. 27, NASA Administrator Jared Isaacman unveiled an updated Artemis framework that shortens launch cadence and standardizes the SLS configuration. Imagery released with the plan showed Orion on an upper stage resembling United Launch Alliance's Centaur V. A March 6 SAM.gov posting from NASA's Marshall Space Flight Center described a sole‑source contract opportunity for ULA to supply Centaur V for Artemis IV and Artemis V. Key facts: - The SAM.gov notice described the opportunity as a sole‑source contract for ULA's Vulcan Centaur V upper stage to be used on SLS Artemis IV and Artemis V. - NASA justified the sole‑source approach by saying Centaur (with minor modifications) is the only existing in‑space stage that meets the SLS upper stage parameters and schedule. - Centaur V is powered by two RL10 engines, holds about twice the fuel of the current ICPS, and is similar in diameter to Orion and its service module. - Vulcan and Centaur V have flown since Vulcan's 2024 debut, and the article notes Vulcan has recorded multiple launches. - Mission roles were reshuffled: Artemis 2 remains a crewed lunar flyby, Artemis 3 is repurposed as a 2027 test flight in low Earth orbit with lander hardware, and Artemis 4 is now the first planned lunar landing mission with Artemis 5 possibly following the same year; beyond Artemis 5 is not specified in the contract. Summary: NASA's announcement both standardizes the SLS upper stage for upcoming missions and accelerates the program's timeline, with Centaur V named for Artemis IV and V in a sole‑source procurement. Near‑term schedules include a possible launch attempt for Artemis 2 in early April and a repurposed Artemis 3 test flight in 2027; what will carry Orion beyond Artemis 5 is undetermined at this time.