22 Flights vs. 8: SpaceX Boss Challenges NASA Moon Fuel Math

The figure 22 has become the focal point of a technical dispute over the feasibility of the next crewed lunar mission. Elon Musk, CEO of SpaceX, publicly challenged this number on Thursday, arguing that the actual requirement for launching astronauts to the Moon in 2028 will be substantially lower. The disagreement centers on the number of Starship launches needed to fill an orbital fuel depot, a critical step for the Artemis IV program.

The conflict arose following a quarterly public meeting of the Aerospace Safety Advisory Panel. Charlie Precourt, a panel member and former NASA astronaut, identified the fueling process as a primary risk factor for the 2028 mission. Precourt stated that current estimates suggest approximately 22 flights are necessary to fuel the lunar lander. He emphasized the need to monitor the numerous required fuelings closely, noting the high risk associated with the complex logistics of orbital refueling.

Musk responded to Precourt's comments after they were shared on social media by Ars Technica journalist Eric Berger. "That's way too high," Musk wrote in reply. "Actual number will be more like 6 to 8." This claim suggests a significant efficiency gain in the vehicle's performance compared to the conservative baseline used by the safety panel.

The discrepancy stems from the physical limitations of the Starship rocket. Because the vehicle consumes nearly all its propellant to reach Earth orbit, it requires external refueling to continue to the Moon. SpaceX's proposed solution involves launching a Starship configured as a storage tank, or depot, into orbit. Subsequent tanker versions of the rocket then fly individually, dock with the depot, and transfer their remaining propellant. Once the depot is full, the lunar lander departs for its destination.

The total number of launches impacts both the timeline and the cost of the mission. Eric Berger estimated that even with a launch rate of two Starships per week by the end of 2027, filling a depot to the panel's 22-flight specification would take approximately three months. The final count depends on how much propellant each tanker can deliver to orbit and how much is lost to boil-off in the cold of space. NASA's estimate appears to be based on current lifting capacity, whereas Musk's lower range assumes a more capable future version of the rocket.

This is not the first time Musk has contested higher launch counts. In 2021, after a government document suggested 16 launches were required, Musk called that figure "extremely unlikely" and predicted a maximum of eight tankers. The resolution of this current debate hinges on hardware that has not yet been fully tested in flight. SpaceX plans to use its upgraded V3 Starship for these operations. Precourt noted that Artemis IV involves a large number of firsts, while also commending NASA Administrator Jared Isaacman for working to clear obstacles for both SpaceX and Blue Origin.