Ever since the first fuzzy images of its surface were captured in 1964, Mars has sparked imaginations worldwide. As Nasa publishes its photographic archives of the red planet, will Elon Musk’s wild predictions of a crewed flight in four years come true?

Last September, Elon Musk used the social media platform he had bought for £35bn to remind the world that he had bigger things on his mind than the forthcoming US presidential election. “The first Starships to Mars will launch in two years when the next Earth-Mars transfer window opens,” he posted on X. “These will be uncrewed to test the reliability of landing intact on Mars. If those landings go well, then the first crewed flights to Mars will be in four years.”

Then came a grand restatement of even more impressive intentions. “[The] flight rate will grow exponentially from there,” he wrote, “with the goal of building a self-sustaining city in about 20 years.” For those who still doubt whether this plan ought to be quite the priority he evidently thinks, he finished with a familiar insistence: “Being multiplanetary will vastly increase the probable lifespan of consciousness, as we will no longer have all our eggs, literally and metabolically, on one planet.”

Although Mars’s volcanoes are no longer active, some of its dune fields are. Wind blowing from the north drives dunes of dark basaltic sand across the floor of a small crater