Centaur 5 Clinches the SLS Upper Stage for Artemis 4 and Beyond
NASA has selected United Launch Alliance’s Centaur 5 as the upper stage for the Space Launch System, starting with Artemis 4 no earlier than early 2028, via a sole-source contract to standardize the fleet to a near-Block 1 configuration. The decision leverages Centaur 5’s RL10 heritage and existing infrastructure, while bypassing alternatives like Boeing’s EUS and Blue Origin’s NGUS due to cost, schedule, and development risks, in line with NASA’s push to accelerate manufacturing and increase launch rates.