Elon Musk really wants to build a Mars city, and it could arrive in the next 30 years. The SpaceX CEO is currently working on the Starship to send the first humans to the red planet, a breakthrough that could pave the way for the creation of an extraterrestrial colony.

“It’s possible to make a self-sustaining city on Mars by 2050, if we start in 5 years & take 10 orbital synchronizations,” Musk told his 25 million Twitter followers Monday evening.

The Starship is critical to these plans. The stainless steel ship is designed to send up to 100 people in space at once, with a Raptor engine that uses liquid oxygen and methane instead of the rocket propellant used for the Falcon 9’s Merlin engines. That’s important because Musk hopes humans will be able to establish propellant plants and create fuel from Mars to return to Earth — or even continue their journey and establish a planet-hopping network.

SpaceX's BFR landing on Mars. SpaceX

SpaceX Going to Mars: What Is an Orbital Synchronization?

The orbital synchronizations Musk is referring to is the point when the Earth and Mars are in closest alignment, which occurs around every 26 months. That’s the ideal time for a launch, as the distance between the two is reduced to around 33.9 million miles. Because the two planets follow an egg-shaped orbit, not every alignment is equal. NASA explains that the 2003 approach was the closest in 60,000 years, and it’s not expected to come that close again until 2287.

These synchronizations have dictated the rhythm of NASA’s launches for nearly 20 years.

Mars Odyssey (orbiter, 2001)

Mars Exploration Rover, Spirit (rover, 2003)

Mars Exploration Rover, Opportunity (rover, 2003)

Mars Reconnaissance Orbiter (orbiter, 2005)

Phoenix Mars Lander (lander, 2007)

NASA skipped the opportunity to complete a launch during the 2009 alignment.

Mars Science Laboratory, aka Curiosity (lander/rover, 2011)

Mars Atmosphere and Volatile Evolution, aka MAVEN (orbiter, 2013)

NASA skipped the opportunity to complete a launch during the 2016 alignment.

Mars InSight (lander, 2018)

Mars 2020 (rover, planned for 2020)

SpaceX could take advantage of the coming synchronizations, due in 2022 and 2024. Indeed, that was Musk’s “aspirational” plan as outlined at the International Astronautical Congress in September 2017. SpaceX would send two unmanned Starships (then known as the BFR) to Mars in 2022, with each one capable of carrying 100 tons of cargo ready for the first humans. The first manned mission would take place in the second synchronization, 2024, sending two manned ships alongside two further unmanned ships. The six ships in total would carry around double the mass of the International Space Station.

The Starship taking off. SpaceX

Musk admitted himself his plan was a long shot. He has since announced plans to send Japanese billionaire Yukazu Maezawa, alongside six to eight artists, on a trip around the moon in 2023. Subsequent comments suggest this could be Starship’s first mission, making a 2022 launch unlikely.

SpaceX Going to Mars: How Will SpaceX Build a City?

Each orbital synchronization would likely be dedicated to building out the base, initially focused on life support and fuel production, to gradually add more habitats and experiments. If all goes well, Musk claims a colony could take shape in seven to 10 years from now.

From there, the plan would be to set up necessary amenities like a recycling system and surface mobility. The first cities could then start researching bigger questions, studying the planet, and trying to understand whether there was ever life on Mars. The architecture would be aimed at supporting these experiments.

Paul Wooster, principal Mars development engineer for SpaceX, said in September 2018 that “the idea would be to expand out, start off not just with an outpost, but grow into a larger base, not just like there are in Antarctica, but really a village, a town, growing into a city, and then multiple cities on Mars.”

Musk predicted at last year’s SXSW how the Martian government would operate, initially using a form of direct democracy.

As for whether Musk himself will go? He says there’s a 70 percent chance.

Experts like Lewis Dartnell, a research scientist at the University of Westminster, have designed visions for how habitats may look to cope with the harsh terrain of Mars. This would include a sealable front door, a greenhouse, solar panels, a gym for retaining muscle mass with a third of the gravity, and specially designed bathrooms to recycle waste. With radio transmissions suffering from a 20-minute delay from Earth, a server would also likely store downloaded movies for later viewing.

Dartnell's house of the future. Hillarys

SpaceX Going to Mars: What Happens Now?

The next step is to test the Starship. SpaceX has built a miniaturized version, dubbed the “hopper,” at its test facility in Boca Chica, Texas. Its Tintin-inspired stainless steel construction looks decidedly futuristic, but it lacks many of the final version’s features, like windows.

SpaceX's final Starship Hopper Twitter/Elon Musk

The plan is to use one of the hopper’s three engines to complete minor jumps off the ground, before moving to more ambitious suborbital flights using all three. The first launch could take place any day now.

From there, the goal is to build an orbital Starship prototype, which could arrive as early as next year. The final version is expected to use 31 engines on its Super Heavy booster, plus seven on the Starship itself. With work well underway on perfecting the Raptors, the full ship could fly very soon.