How Many Flights To Fuel A Moon Lander?

A single number could determine the schedule for returning humans to the Moon.

NASA has historically declined to specify the exact number of SpaceX Starship launches required to refuel a lunar lander in Earth's orbit, a metric that has fluctuated significantly over time. Officials have provided a range of figures, from a previous estimate of 'high single digits to the low double digits' to other statements suggesting 'high teens.' The plan has always been for a 'depot' Starship to be launched first, followed by a series of 'tanker' Starships to transfer the necessary liquid oxygen and methane propellant for a journey to the Moon.

The issue is that the required number of launches may be higher than previously anticipated. This concern comes as SpaceX has not yet demonstrated the kind of dramatic increase in payload capacity that would reduce the number of tanker flights needed to fuel a lander. Some officials worry that without this improvement, the Starship rocket may not be ready to support a lunar landing in time for the current Artemis program timeline.

At a meeting on Thursday, the NASA Aerospace Safety Advisory Panel addressed these risks. Panel member Charlie Precourt, a former NASA astronaut, discussed the challenges associated with the Artemis Program's goal of landing people on the Moon.

This uncertainty is not new. For years, NASA has been reluctant to commit to a specific number of launches. In 2023, the then-director of NASA's Human Landing System program, Lisa Watson-Morgan, said, 'We have a general idea, but I’m reluctant to say exactly what that is.' The agency's position has consistently been that a firm number cannot be provided, and the latest statements from safety officials suggest that situation has not changed.

The meeting did not resolve the issue. NASA has not provided a new, official estimate for the number of Starship launches required to support a Moon landing, and the timeline for when such a number might be available remains unclear.