Welding issues arise during Artemis 3 moon rocket's assembly, but mission still on track: report

One of the first rockets launching crewed moon missions in more than 50 years is having a production problem, a report suggests.

The core stage for the powerful Space Launch System (SLS) rocket, set to launch the four-astronaut Artemis 2 around the moon no earlier than November 2024, is under assembly at NASA's Michoud Assembly Facility in New Orleans. But the core stage for Artemis 3 is facing "weld issues," a report from NASA Spaceflight suggests. So far, the Oct. 10 report adds, there are no expected delays to either launch because of that issue.

NASA officials published a blog update about Artemis 2's core stage later on Friday that did not discuss the reported issue. Boeing, in a response to Space.com on Oct. 20, said the issue "is not affecting the core stage 2 build or delivery schedule" for Artemis 2. As for Artemis 3, "the nonconformance was identified and in the process of being resolved on core stage 3."

Related: Why Artemis 2 moon launch with astronauts is different from Artemis 1

The NASA Spaceflight report suggested that the welding issue on Artemis 3 is being worked through, and that NASA officials are optimistic the core stage will be finished on schedule. (Supply chain issues also held up some elements of production of Artemis 2 earlier in the year.)

"I don't want to get into too many of the technical details of that [welding], as Boeing is still working through and completing the root cause and corrective action, but I will say that we are nearing the end," Jonathan Looser, NASA SLS core stage design team lead, said in the report, referring to the welding issues.

The welding problems are occurring on the SLS liquid oxygen tank aft dome and have been persisting "for the last several months," Looser added. The nature of the issues was not specified. Space.com asked NASA officials twice for comment before publication. After the article's publication, officials with NASA said the non-conformance on Artemis 3 "was identified as part of routine quality assurance operations and is being resolved. The rocket is on track to support the Artemis 3 launch." Artemis 2 is also on track, they emphasized.

All four of the core stage's RS-25 engines were successfully mounted on Artemis 2 as of late September, and other work is moving forward this month. The assembly team "will focus efforts on the complex task of fully securing the engines to the stage and integrating the propulsion and electrical systems within the structure," the blog post added. The team includes people from Boeing and Aerojet Rocketdyne, an L3Harris company that is responsible for the RS-25 engines, which were repurposed from the space shuttle program.

The liquid oxygen tank is the only major structure still awaiting assembly for Artemis 2, the report added. Three of the tank's four pieces are ready (that other work was finished by late 2022) and are awaiting the tricky fourth piece. Also, the report suggests other pieces of the core stage and exploration upper stage structures cannot be welded until the liquid oxygen tank is complete.

Artemis 2's round-the-moon mission isn't the first for the larger Artemis program; Artemis 1 successfully sent an uncrewed Orion into lunar orbit and back to Earth in late 2022. The next mission after Artemis 2, Artemis 3, aims to land humans on the moon in 2025 or 2026. NASA has cautioned, however, that SpaceX's Starship landing system may not be ready in time for that target date, and the agency is prepared to make an alternate mission plan that would push the touchdown to Artemis 4.

Editor's note: This article was updated on Oct. 20 to clarify with comments from Boeing that the weld issues affect the Artemis 3 mission's Core Stage 3, not the core stage for Artemis 2. This article was again updated on Oct. 23 with comments from NASA.