Elon Musk has repeatedly emphasized that no matter how financially successful SpaceX may be, the company will have failed in his eyes if the primary objective – the colonization of Mars – is not achieved. Musk’s biographer Walter Isaacson quotes him as saying: “The lens of getting to Mars has motivated every SpaceX decision.” One example of this is that Musk chose methane as the fuel for Starship. He chose methane because it can be extracted on Mars. This will significantly reduce the amount of fuel that Starship needs to carry as it will not need fuel for both the outbound and return trips. Musk is planning to send an unmanned rocket to Mars, which will generate methane fuel on site.
However, on February 9, Musk posted on X: “For those unaware, SpaceX has already shifted focus to building a self-growing city on the Moon, as we can potentially achieve that in less than 10 years, whereas Mars would take 20+ years. The mission of SpaceX remains the same: extend consciousness and life as we know it to the stars. It is only possible to travel to Mars when the planets align every 26 months (six month trip time), whereas we can launch to the Moon every 10 days (2 day trip time). This means we can iterate much faster to complete a Moon city than a Mars city. That said, SpaceX will also strive to build a Mars city and begin doing so in about 5 to 7 years, but the overriding priority is securing the future of civilization and the Moon is faster.”
Musk has therefore by no means abandoned his Mars objective but has postponed it. However, the justification is not convincing, because Musk knew the fact that missions to Mars are only possible every 26 months while launches to the Moon can occur every ten days for decades; this is not a new insight.
It is more likely that NASA has put pressure on Musk because it fears that the Chinese may reach the Moon first — and the United States does not want to concede that lead. NASA’s SLS rocket has struggled with significant delays and massive cost overruns, and the new administrator Jared Isaacman, a friend of Musk, has apparently become nervous about whether success would be possible without Musk and Jeff Bezos.
Until now, Musk had taken the view that it was relatively unimportant who would return to the Moon 60 years after the first US lunar landing — what mattered was who would reach Mars first. Now he appears to be accommodating NASA’s wishes and priorities.
Some may interpret this as evidence of Musk’s dependence on NASA, but economically this is incorrect, since no more than five to ten percent of SpaceX’s revenue comes from NASA contracts. A more plausible explanation is that investment banks advised him that, for the IPO planned for June, the Mars narrative sounded too much like science fiction. As a result, he is temporarily emphasizing topics such as data centers in space and a lunar settlement, because these appear more plausible for the equity story.
Musk has been strongly influenced by Robert Zubrin, the founder of the Mars Society, who has now criticized Musk in an article published on the organization’s website. Responding directly to Musk’s post on X, he wrote: “It won’t work. The materials required to support a growing civilization do not exist on the Moon.”
Zubrin elaborates: “We are carbon-based life forms. We are made of carbon compounds, as is everything we eat or wear, and most of the things that we use. There is no carbon on the Moon. The other essential components of life are water and nitrogen. Aside from ice trapped in ultracold (–230°C), permanently shadowed craters near the lunar south pole, water exists on the Moon only in parts-per-million concentrations within the regolith. Nitrogen is effectively absent, as are concentrated mineral ores.
The Moon does contain oxygen, but only chemically bound in rock. Extracting it requires complex, energy-intensive industrial processes operating at extremely high temperatures. This would sharply increase the cost and drastically shorten the operational lifespan of the necessary equipment. In contrast, the materials necessary to support life and civilization — including carbon, oxygen, nitrogen, water and enriched mineral ores — are widely available in readily usable forms on Mars.
The Mars-to-Moon shift has other significant flaws. While the Moon is indeed closer to Earth, the rocket propulsion requirement to travel one way from Earth to the lunar surface is 50% greater than that needed to go to Mars. The return leg would be even more challenging: producing propellant on the Moon is far more difficult than doing so on Mars, effectively tripling the propulsion requirements for a round trip.”
At first glance, this final argument appears paradoxical, because the Moon is only about 384,000 km away, whereas Mars is on average more than 200 million km from Earth. However, spacecraft approaching Mars can decelerate significantly by using the planet’s atmosphere, while the Moon has no atmosphere at all. Every reduction in velocity must therefore be achieved using rocket engines, which consumes large amounts of fuel. The return journey increases the difference even further. Mars possesses a CO2 atmosphere and abundant water ice, from which methane and oxygen can be produced using the Sabatier process. This is precisely the basis of the SpaceX concept: producing fuel on site.
I do not believe that Musk has abandoned his overarching goal. Whether the postponement makes sense is another question, but it is likely that Mars will remain Musk’s ultimate objective, just as it has been from the beginning and continuously until today.
