NASA Panel Reveals 22-Launch Requirement for Lunar Mission

A former NASA astronaut has disclosed a new, specific figure for the number of rocket launches required to support a crewed lunar landing, ending years of official ambiguity. Speaking at the quarterly meeting of the NASA Aerospace Safety Advisory Panel on Thursday, Charlie Precourt identified 22 as the current estimate for the number of Starship flights needed to assemble a lunar lander in low-Earth orbit.

This figure represents the total amount of propellant, specifically liquid oxygen and methane, that must be delivered to a 'depot' vehicle to enable it to travel to the Moon, land, and return to lunar orbit. The disclosure marks a significant shift in transparency for a metric that has long been treated with unusual caution by the space agency.

For years, the exact number of tanker flights required has been a moving target. NASA officials have generally avoided pinning down a precise count, often responding that they do not know for sure and therefore will not speculate. In 2023, Lisa Watson-Morgan, then-director of NASA’s Human Landing System, told Ars Technica that while the agency had a general idea, she was reluctant to state the exact number. She later characterized the requirement as being in the 'high single digits to the low double digits,' suggesting approximately a dozen launches.

The new estimate of 22 is notably higher than previous internal guesses, which some officials had pegged in the 'high teens.' This increase suggests that the lift capacity of the Starship vehicle may not be improving as rapidly or significantly as had been hoped. The expectation was that dramatic improvements in lift capacity would reduce the number of tanker flights needed to fill the depot, but current data indicates that this optimization may not be occurring soon enough to meet tight timelines.

The Artemis Program aims to return humans to the Moon this decade. A core part of this strategy relies on SpaceX’s Starship rocket to perform the critical role of landing astronauts on the lunar surface. However, concerns are growing among some NASA officials that the vehicle’s performance trajectory may not allow it to play a meaningful role in the program’s near-term goals if the launch count remains high.

The logistics of such a mission are complex. SpaceX would be required to launch a dedicated 'depot' Starship, followed by multiple 'tanker' Starships. Each tanker flight would carry propellant to fill the depot, which acts as a refueling station in low-Earth orbit. Only once the depot is fully loaded can the crewed lander depart for the Moon. The new estimate implies that roughly 21 tanker flights would be necessary to support a single depot, a substantial operational undertaking.

Precourt’s comments came as part of a broader discussion on risks associated with the Artemis Program. As a member of the Aerospace Safety Advisory Panel, he is tasked with identifying potential hazards in NASA’s human spaceflight activities. His disclosure of the 22-launch figure provides a concrete data point for stakeholders evaluating the feasibility and safety of the lunar lander architecture.

The shift from vague estimates to a specific number of 22 launches highlights the engineering challenges involved in assembling large vehicles in space. While previous estimates suggested that improvements in rocket performance could lower this number, the current baseline indicates that the agency is planning for a higher volume of launches to ensure mission success.

What happens next will depend on whether SpaceX can demonstrate significant gains in Starship’s payload capacity in the coming months. If the vehicle’s performance improves dramatically, the number of required tanker flights could decrease, easing the logistical burden on NASA. However, if the current estimate holds, the Artemis timeline may face further pressure as the agency coordinates a complex series of launches to fuel the lunar lander.

For now, the figure of 22 launches stands as the latest official benchmark. It serves as a reminder of the immense scale of the task ahead as NASA and its partners work to restore human presence to the Moon. The coming weeks will be critical in determining whether this number is a floor or a starting point for further optimization.