"NASA's SLS Exploration Upper Stage Enters Qualification Phase"

NASA's Space Launch System (SLS) rocket's first major upgrade, the Exploration Upper Stage (EUS), is moving into the qualification phase of development at the Michoud Assembly Facility in New Orleans. The EUS, part of the new SLS Block 1B configuration, is set to debut on the Artemis IV mission in 2028. Boeing, the prime contractor for the EUS, is working on validating weld schedules and assembly techniques, with the EUS employing new adapters and four RL10 engines. The development involves the use of advanced welding tools and aluminum-lithium alloy for weight savings. The EUS structural test article is being prepared for qualification, with plans for assembly and testing in preparation for the first EUS/Block 1B flight on Artemis IV.