— Elon Musk (@elonmusk) September 7, 2024 Now he's test flying the largest, most powerful rocket in history and plans to fly it as routinely as an airliner. So when he starts talking about going to Mars, he gets a bit more attention than back in 2014 when he breezily promised to land humans on Mars in a Dragon capsule inside a decade. "The first Starships to Mars will launch in 2 years when the next Earth-Mars transfer window opens," said Musk in a September 7, 2024 post on X (formerly Twitter). "These will be uncrewed to test the reliability of landing intact on Mars," he added. "If those landings go well, then the first crewed flights to Mars will be in 4 years. "Flight rate will grow exponentially from there, with the goal of building a self-sustaining city in about 20 years. 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." In terms of celestial mechanics, the timing is logical. The Earth and Mars align favorably for travel between them every 26 months, with the next window for the 259-day journey in 2026 – 2028 is also a favorable year. As to technology, Starship has been making considerable progress in the past year, with a fifth test flight slated for the near future. If all goes to plan, both stages of Starship will be able to return to their launch site where they will be caught in pairs of gigantic metal arms, after which they can be quickly refurbished for the next flight. Eventually, Musk wants to build an armada of 1,000 ships to set up a colony on the Red Planet, which will require no less than 10 launches per day to assemble and fuel the fleet. In addition, SpaceX has been contracted by NASA to build the landing ship for the space agency's Artemis Moon outpost program, which will provide the company with a considerable degree of technological experience in that field.