How many rockets does it take to put astronauts on the Moon? NASA’s safety advisers and Elon Musk are 14 to 16 launches apart on the answer.
At its quarterly public meeting on Thursday, NASA’s Aerospace Safety Advisory Panel named the refueling of SpaceX’s lunar lander as a major risk for Artemis IV, the mission meant to land a crew in 2028. Panel member Charlie Precourt, a former astronaut, said: “We need to keep our eyes on numerous required fuelings for the lander. I think the last estimate is around 22 flights.” Ars Technica’s Eric Berger posted the remark on X, and Musk answered within hours. “That’s way too high,” he wrote. “Actual number will be more like 6 to 8.”
Why a Moon trip needs a gas station
Starship burns nearly all its propellant just getting to Earth orbit, so it cannot go on to the Moon without a top-up. SpaceX’s solution is an orbiting fuel depot, which is itself a Starship working as a storage tank. Tanker Starships launch one after another, dock with it and pump in their leftover propellant. When the depot is full, the lander version launches, docks, fills up and sets off.
Every tanker is a complete rocket launch, so the count drives time, cost and risk before anyone leaves the ground. Berger worked out that even if SpaceX manages two Starship launches a week by the end of 2027, filling the depot at the panel’s figure would take about three months.
Where the two numbers come from
The gap rests mostly on two questions: how much propellant each tanker delivers to orbit, and how much is lost on the way. Starship’s fuel and oxygen are kept extremely cold, and some boils off while waiting in orbit. More is lost in every transfer. NASA appears to be working from what Starship can lift today. Musk’s range assumes a more capable rocket, and Teslarati noted earlier this year that SpaceX plans to do the refueling with its upgraded V3 Starship.
Musk has been here before. In 2021, after a government document suggested 16 launches, he called that “extremely unlikely” and said eight tankers would be the most needed.
Much of the answer hangs on hardware that has not yet finished its test flights. Precourt called Artemis IV a mission with “a large number of firsts,” though he also credited NASA Administrator Jared Isaacman’s team for clearing obstacles for both SpaceX and Blue Origin. Blue Origin’s Blue Moon lander does not need orbital refueling for its first mission.
NASA holds a public update on its Artemis lunar plans on October 23, and any change to the landing system timeline or the refueling flight count is likely to surface there.
Sources
- Musk disputes NASA safety panel's lunar launch estimates
- The Starship moon landing number NASA and Elon Musk can’t agree on
- Musk Says 6-8 Flights, NASA Panel Says 22
Photo: Gage Skidmore (CC BY-SA 4.0)
