BERLIN — As SpaceX prepares for its next Starship test flight, a NASA official said that the use of that vehicle for Artemis lunar landings will require “in the high teens” of launches, a much higher number than what the company’s leadership has previously claimed.

In a presentation at a meeting of the NASA Advisory Council’s human exploration and operations committee Nov. 17, Lakiesha Hawkins, assistant deputy associate administrator in NASA’s Moon to Mars Program Office, said the company will have to perform Starship launches from both its current pad in Texas and one it is constructing at the Kennedy Space Center in order send a lander to the moon for Artemis 3.

SpaceX’s concept of operations for the Starship lunar lander it is developing for the Human Landing System (HLS) program requires multiple launches of the Starship/Super Heavy system. One launch will place a propellant depot into orbit, followed by multiple other launches of tanker versions of Starship, transferring methane and liquid oxygen propellants into the depot. That will be followed by the lander version of Starship, which will rendezvous with the depot and fill its tanks before going to the moon.

Exactly how many launches will be required has been a point of debate since Starship’s selection by NASA for the first HLS award in 2021. Neither NASA nor SpaceX have given firm numbers recently. A paper about the HLS program presented at the 2023 International Astronautical Congress by NASA, for example, mentioned only “a series of reusable tanker Starship variants” that would be launched to fill the depot before the Starship lander is launched, without giving a number.

“It’s in the high teens in the number of launches,” Hawkins said. That’s driven, she suggested, about concerns about boiloff, or loss of cryogenic liquid propellants, at the depot.

“In order to be able to meet the schedule that is required, as well as managing boiloff and so forth of the fuel, there’s going to need to be a rapid succession of launches of fuel,” she said.

That schedule will require launches from both the existing Starship pad at Boca Chica, Texas, as well as the one SpaceX is building at KSC’s Launch Complex 39A, adjacent to the current pad used for Falcon 9 and Falcon Heavy launches. “We should be able to launch from both of those sites,” she said, on a “six-day rotation.”

Critics of NASA’s selection of Starship for HLS have pointed to the number of launches as a weakness in the architecture. The Government Accountability Office, in its rejection of protests by Blue Origin and Dynetics of the Starship HLS award in 2021, noted that SpaceX required 16 launches overall for a Starship lunar lander mission.

Elon Musk, chief executive of SpaceX, disagreed, calling the need for 16 launches “extremely unlikely” in an August 2021 social media post. He said a “max of 8” tanker launches should be needed to fuel the Starship lander, adding it could be as few as four.

Development of the Starship lander has frequently been seen as on the critical path for the Artemis 3 mission, given that both the Space Launch System and the Orion spacecraft have both flown. However, earlier in the committee session, Jim Free, associate administrator for exploration systems development, argued that there are many more factors going into that mission.

“We have a whole bunch of new stuff that comes together for [Artemis] 3,” he said, from new spacesuits being developed by Axiom Space to the addition of a docking port on Orion. “Yes, the lander is absolutely important. We can’t go anywhere without it. But, we also can’t go anywhere without the suits.”

His comments came a day before the scheduled launch of the second integrated Starship/Super Heavy vehicle, designated OFT-2, that is a key milestone in the development of the Starship vehicle and thus for Artemis. “I hope everybody across all of these programs is cheering that on,” he said of the launch. “We need OFT-2 to go.”