SpaceX’s plans to use its Starship spacecraft for future Moon missions have sparked fresh discussion following contrasting estimates about the number of launches needed to complete orbital refueling. While a member of NASA’s Aerospace Safety Advisory Panel believes approximately 22 tanker flights could be necessary, Elon Musk has challenged that assessment, suggesting that between six and eight launches may be sufficient.
The disagreement highlights the technical difficulties involved in preparing Starship for a lunar journey and raises questions about the time, resources and operational requirements associated with the ambitious project.
The issue was discussed during a meeting of NASA’s Aerospace Safety Advisory Panel on October 22, 2026. Charlie Precourt, a former astronaut and member of the advisory group, addressed the challenges associated with SpaceX’s proposed lunar landing system.
According to Precourt, the spacecraft could require approximately 22 launches to gather enough propellant before beginning its journey toward the Moon. His assessment attracted attention because orbital refueling is considered one of the most demanding parts of the Starship development programme.
Musk subsequently responded to the estimate, suggesting that the required number of tanker launches would be considerably lower. The SpaceX chief put forward a projection of six to eight flights, creating a noticeable difference between his expectations and the figure discussed by the NASA panel member.
Starship’s lunar architecture relies on a refueling system that differs from conventional space missions. Rather than carrying all the necessary fuel during its initial launch, the spacecraft is designed to receive additional propellant while positioned in Earth’s orbit.
Under the proposed arrangement, SpaceX would first launch an orbital fuel depot. Specially designed tanker versions of Starship would then make repeated journeys to deliver liquid oxygen and liquid methane. Once sufficient propellant has been collected, the lunar spacecraft would receive its fuel before continuing toward the Moon.
However, the process involves several technical challenges. Each tanker must successfully reach orbit, connect with the designated storage vehicle and transfer its fuel efficiently. Repeating these operations requires reliable launch systems and precise coordination between multiple spacecraft.
Fuel storage also presents difficulties because Starship uses cryogenic propellants that must remain at extremely low temperatures. Some fuel can gradually evaporate during storage, potentially affecting how much remains available for the lunar journey.
The efficiency of fuel transfers, the spacecraft’s carrying capacity and the amount of propellant lost during storage will all influence the final number of launches required.
NASA and SpaceX have yet to establish a definitive figure for the complete refueling process. Musk’s lower estimate represents his expectation, while the larger figure reflects concerns raised during the advisory panel’s discussion.
The outcome is particularly important for NASA’s Artemis programme, which relies on Starship as one of the systems intended to transport astronauts between lunar orbit and the Moon’s surface.
SpaceX must demonstrate that its spacecraft can conduct large-scale propellant transfers in orbit before the system can be considered ready for operational lunar missions. These demonstrations will help engineers understand whether the proposed refueling architecture can work reliably and safely.
The difference between the two estimates could also have financial and scheduling implications. A smaller number of tanker launches could reduce the resources required to prepare the spacecraft, while a larger number would introduce additional launch operations and logistical demands.
NASA’s lunar exploration ambitions therefore depend partly on SpaceX overcoming the technical obstacles associated with orbital refueling. The company will need to demonstrate the system’s capabilities through testing rather than relying solely on projected performance.
For now, the debate between the 22-flight estimate and Musk’s six-to-eight-launch projection remains unresolved. Future Starship tests and successful fuel-transfer demonstrations are expected to provide a clearer picture of what the lunar mission will actually require.
As development continues, the ability to refuel Starship efficiently in space will remain a crucial factor in determining how soon the spacecraft can support NASA’s plans for returning astronauts to the lunar surface.
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