NASA Administrator Jim Bridenstine proclaimed a milestone for the Space Launch System (SLS) today at the Michoud Assembly Facility (MAF) where it is built. Called “core complete” it signifies that the main part of the first SLS rocket is ready to be shipped to Stennis Space Center for testing, another step along the way to the first launch. There was no news, however, about when that launch will take place.

SLS is a Saturn V-class booster that NASA will use to send astronauts back to the lunar surface via a small space station, Gateway, in lunar orbit. The goal is for the first woman and next man to land on the Moon in 2024.

This Block 1 version of SLS consists of the Boeing-built core stage powered by four Aerojet Rocketdyne RS-25 engines repurposed from the space shuttle program; two Northrop Grumman solid rocket boosters (one on each side); and a Boeing upper stage called the Interim Cryogenic Propulsion Stage (ICPS) derived from the United Launch Alliance’s Delta IV second stage with an Aerojet Rocketdyne RL-10B2 engine.

The core stage is built at NASA’s Michoud facility, near New Orleans. Challenges have delayed the program for several years, but today the first one is complete and ready to move on to the next step, a Green Run test at nearby Stennis Space Center near Bay St. Louis, MS. During the test, all four engines will be fired for 8 minutes, the duration they must work to achieve orbit.

“Go SLS! Core stage complete,” exclaimed Bridenstine as he stood between the core stage, laying horizontally amidst scaffolding, and a huge sign: “Artemis Core Stage Completely Assembled|Preparing to Ship.”

Calling it “NASA’s Christmas present to America,” he said the core stage would move from Michoud to Stennis by the end of the year.

He punted, however, when asked when the first launch, Artemis I, will take place. Previously designated Exploration Mission-1 (EM-1), NASA originally promised the first launch by November 2018. That slipped to a period between December 2019 and June 2020, but more delays ensued.

NASA officials currently say they are internally working toward a launch date at the end of 2020, though Bridenstine told Congress months ago that it would slip to 2021. He dismissed the head of the Human Exploration and Operations Mission Directorate (HEOMD), Bill Gerstenmaier, and his deputy in charge of SLS, Bill Hill, in July. Since then he has insisted that he will not officially set a new date until Gerstenmaier’s replacement has had time to review the program since he will be held accountable for meeting it. That person is Doug Loverro who reported for duty last week. Loverro also was at Michoud today, but only to introduce himself to the workforce and begin his assessment.

Bridenstine was asked again today about the per-launch cost of SLS. As he said during an agency Town Hall meeting last week, the answer depends on how many are purchased. The cost goes down if more are bought. The White House estimated it at $2 billion per launch in a recent letter to Congress, but Bridenstine thinks it could be half that depending on negotiations with Boeing and the number bought.