The conquest of Mars: How possible is Elon Musk's most ambitious dream, according to science?

Elon Musk 's ultimate ambition as SpaceX commander-in-chief is not limited to launching satellites or reusable rockets: the tycoon dreams of a fleet that can evacuate humanity when the Earth collapses and establish colonies on Mars .

However, on this interplanetary horizon there are more doubts than certainties and more and more scientists are questioning the viability of these messianic promises .

The desire to explore other worlds is not just a matter of scientific impulse; it is deeply linked to a capitalist logic : each annexed territory opens the door to new opportunities.

Throughout history, great human migrations have been linked to overpopulation, resource depletion, the pursuit of freedom, and competitive advantage. Mars now appears as the new frontier for projecting that same desire for expansion.

However, some experts still disagree with this colonizing vision. And this isn't due to Starship 's technical failures—it failed five of its nine launches —since it is an experimental rocket. The real controversy revolves around the scientific and ethical viability of this project.

One of the most vocal detractors is astrophysicist Adam Becker , who called it “the stupidest thing anyone could ever pursue” when asked about the possibility of moving to the red planet.

In his recent book , More Everything Forever , Becker argues that Musk and Jeff Bezos ’s aspirations to conquer Mars are nothing more than “science fiction fantasies” disconnected from the technological, scientific, and moral realities of the present.

To back up his claims, Becker outlines three extreme scenarios : an asteroid impact comparable to the one that wiped out the dinosaurs, a global nuclear war, and brutal climate change.

Even in the midst of a global catastrophe—such as those depicted in apocalyptic movies—Earth, the scientist maintains, would still offer more favorable conditions than any extraterrestrial alternative .

Not even the worst disaster could completely erase the natural advantages of our world : breathable air, stable gravity, abundant water. As Becker concludes, settling in would mean living in sealed bubbles , where a simple technical oversight could be lethal.

With no room for error, survival would depend entirely on engineering . On the other hand, the Earth—even devastated—would retain fertile areas and a real chance of rebuilding.

One of the greatest technical challenges is the return of these contingents to Earth, since return windows open every 26 months . This limitation requires the development of extremely robust and reliable systems capable of sustaining life for long periods.

While creating a habitable artificial environment is technically possible, the cost of transportation remains a key obstacle, though it is expected to become cheaper with the constant back-and-forth.

Musk himself estimated that a routine of 1,000 launches would be needed to establish a permanent settlement on Mars. Each mission would transport infrastructure, tools, and food, along with emigrants, to take the first steps.

“The critical breakthrough we need to become a galactic civilization is to make space travel as common as commercial flights,” Musk said.

From a financial perspective, the challenge is as great as the goal itself: there is no estimate of how much this space adventure would cost. For reference, the Apollo program—which successfully reached the Moon in just six missions—required more than $280 billion , adjusted to current values.

Adam Becker isn't the only one who questions Musk's ambitions. Michael Meyer , lead scientist for NASA's Red Planet exploration program, warns that its economic viability will remain uncertain for at least the next 100 years .

Meyer lists some very specific reasons: the atmosphere contains almost no oxygen and available water is extremely scarce , which prevents the development of agriculture or the establishment of a functional hydrological cycle.

From this perspective, the real obstacle for Elon Musk isn't landing Starship at a strategic point, but creating conditions even remotely similar to life on Earth. Even in the perfect environment, humans would be forced to live confined in pressurized chambers for life.

And even if the most dire predictions come true—air pollution, nuclear disaster, or an asteroid impact—Earth would still offer minimal habitability conditions that Mars, for all its futuristic epic, cannot match.

Even with an altered atmosphere, the blue planet would maintain its density, rich in nitrogen and oxygen, with a pressure of 1 bar at sea level. This vital mix would allow breathing—with assistance, perhaps—but without the need for a spacesuit.

In contrast, the Martian atmosphere is a mere shadow of that of Earth: 0.6% of that of Earth, composed of 95% carbon dioxide , with no available oxygen, and a surface pressure so low (0.006 bars) that water cannot remain liquid; it simply sublimates, transforming from ice into vapor.

But the atmosphere isn't the only obstacle. Mars lacks a global magnetic field, leaving its surface defenseless against solar and cosmic radiation. Any attempt to establish a colony would require underground shelters or armored structures with 24-hour protection systems.

In contrast, the Earth's magnetosphere would continue to function as a natural shield, even after a major shock.

Added to this is the extreme climate . The average temperature on Mars is around -63°C. All water is frozen , either at the poles or trapped beneath the regolith.

On Earth, an event like nuclear winter could cool the planet, but the oceans—with their 1.4 billion cubic kilometers of water—would still act as a thermal stabilizer . Even if contaminated or partially frozen, the water would be treatable and usable, at least with basic technology.

And even if the biosphere were to collapse, niches of biological resilience would remain. Microorganisms could survive in geothermal refuges, on the seafloor, or in isolated caverns. The Earth's soil would retain organic matter and key nutrients to restart agricultural processes.

On Mars, however, the soil is toxic : high levels of perchlorates pose a serious risk to human health and make any attempt at cultivation difficult.

Martian gravity—just 38% of Earth's—poses another unknown. Preliminary studies suggest that prolonged exposure could affect muscles, bones, and cardiovascular function .

Added to this is the difficulty of accessing basic resources. While ice deposits and signs of possible underground brines have been detected, everything is buried, inaccessible, and surrounded by hostile conditions.

For now, Mars remains more of an idea than a solution . A survival experiment that, without a colossal technological infrastructure, offers no real guarantees. Faced with this, a damaged Earth remains the only possible home .