Amid competing priorities, Boeing redesigns NASA SLS Exploration Upper Stage

After its debut was postponed and production plans suspended, NASA gave its OK in June to a set of design changes proposed by prime contractor Boeing for the Exploration Upper Stage (EUS). EUS was planned to become the upper stage for NASA’s Space Launch System (SLS) rocket on its second launch, but last year the space agency requested a study of possible changes after Congress decided to fly more SLS launches with its current interim upper stage.

Boeing provided NASA with choices to optimize the stage for lunar payloads at the end of 2018, but the future of the stage came into question at the beginning of this year. With the delay in its first launch, funding was first cut in half in the last fiscal year and then the White House proposed completely defunding it this year.
Shortly thereafter, the Artemis Program was started with the goal to land U.S. astronauts on the Moon by the end of 2024 and with its own funding needs, EUS is not a part of the White House’s lunar landing plans. Congress has been the main champion of development and application of the stage, including restoring funding to its previous level, and if ...