SpaceX CEO Musk Counters NASA Panel With Lower Lunar Fuel Estimate

The projected timeline for the 2028 lunar mission may shift depending on how many rocket launches are required to fill an orbital fuel depot. Elon Musk stated that the actual number of tanker flights needed will be between six and eight. This figure stands in sharp contrast to the estimate of 22 launches provided by a NASA advisory panel. The discrepancy determines how long crews must wait on Earth and how much propellant must be transferred in space.

The dispute began at the Aerospace Safety Advisory Panel's quarterly public meeting held on Thursday. Panel member Charlie Precourt, a former NASA astronaut, identified lander fueling as a primary risk for Artemis IV. Precourt noted that the last estimate for the required fuelings was around 22 flights. He emphasized that the mission requires close monitoring of this logistics chain. The comment was shared on the social platform X by Ars Technica reporter Eric Berger. Musk responded directly to the post, describing the panel's number as way too high.

The core issue involves the physical limitations of the Starship vehicle. The rocket uses nearly all its propellant to reach Earth orbit. It cannot proceed to the Moon without being refueled in space. SpaceX plans to launch a Starship configured as a storage depot first. Tanker Starships will then fly one at a time to dock with this depot and transfer their remaining propellant. Once the depot is full, the lunar lander version of the rocket will launch, dock, and depart for the Moon.

Each tanker flight represents a complete rocket launch. More launches mean more time, higher costs, and increased chances for technical issues. Berger estimated that even with two Starship launches per week by the end of 2027, filling a depot at the panel's rate would take about three months. The total count depends on how much propellant each tanker delivers to orbit. Starship fuel and oxygen are kept at extremely low temperatures. Some propellant boils off while waiting in orbit, and more is lost during each transfer.

NASA appears to base its estimate on Starship's current lift capability. Musk's lower range assumes a more capable vehicle. Musk has challenged higher counts in the past. In 2021, after a government document suggested 16 launches, he called that figure extremely unlikely. He stated at the time that eight tankers would be the maximum needed. The resolution of this debate hinges on hardware SpaceX has not yet fully flown.

SpaceX plans to conduct refueling operations with its upgraded V3 Starship. Precourt described Artemis IV as carrying a large number of firsts for the space program. He also commended NASA Administrator Jared Isaacman for working to remove obstacles for both SpaceX and Blue Origin. The Blue Moon lander from Blue Origin does not depend on orbital refueling for its first mission.