The overhaul in the flight lineup came just two days after NASA’s new moon rocket returned to its hangar for more repairs, and a safety panel warned the space agency to scale back its overly ambitious goals for humanity’s first lunar landing since 1972.

At the core of Isaacman’s concerns is the low flight rate of the SLS rocket and Artemis missions. During past exploration missions, from Mercury through Gemini, Apollo, and the Space Shuttle program, NASA has launched humans on average about once every three months. It has been nearly 3.5 years since Artemis I launched.

That's one small step for a man. One very expensive leap for the United States. Okay, sure, some would argue focusing on the total cost of the Apollo program defeats the purpose. Stepping onto the lunar surface was a remarkable endeavor with no arguments there