Elon Musk, the founder of SpaceX, wants to build cities on Mars.

SpaceX is developing a system called the Big Falcon Rocket to reach the red planet as soon as 2022.

A recent presentation by SpaceX's lead Mars mission engineer, Paul Wooster, revealed new details about the plan.

SpaceX seems to view itself primarily as a transportation company, and wants outside help to develop its surface missions and Mars colonization technologies.

A top engineer at SpaceX has shared new details about the rocket company's as-yet nebulous plans to launch the first people toward Mars in 2024 and eventually colonize the red planet.

Paul Wooster, SpaceX's principal Mars development engineer, gave a short presentation about the scheme on August 25 at the 21st annual International Mars Society Convention in Pasadena, California. On Wednesday, the Mars Society posted the talk to YouTube.

Much of what Wooster said echoes what his boss Elon Musk has described in presentations, academic studies, and casual remarks.

Musk has repeatedly said his "aspirational" timeline is to launch cargo missions to Mars starting in 2022, with crewed missions following in 2024. However, he ultimately hopes to build cities on Mars and permanently colonize the planet as a "backup drive" for humanity, just in case a global cataclysm ruins Earth as we know it.

Wooster highlighted some specific problems SpaceX faces, plus some open-ended questions about what happens after the company lands its first spaceships on the Martian surface.

He also signaled that the company needs outside help to address these challenges.

"We at SpaceX are very much focused on the transportation," Wooster said during his talk. "In terms of what will be needed on Mars, this is an area where SpaceX is quite interested in the capabilities, but also something where I think lot of people beyond just SpaceX can really contribute."

How SpaceX plans to reach Mars

SpaceX's ability to not only reach Mars, but also begin setting up a sustainable outpost, will hinge entirely on its Big Falcon Rocket, or BFR.

The system is designed with two sections: a 191-foot-tall fully reusable booster, plus a 157-foot-tall spaceship. The booster will heave the spaceship dozens of miles above Earth, then detach and land itself for inspection and refueling. After detaching from the booster, the spaceship will fire its own engines to finish reaching orbit around Earth.

Once there, the ship will be nearly out of fuel. So nearly identical tanker spaceships (maybe a dozen of them, according to some back-of-the-envelope calculations on Reddit) would be launched to refuel the main spaceship.

A diagram showing how SpaceX plans to establish a base and methane-fueling depot on Mars. Elon Musk/SpaceX; New Space/Mary Ann Liebert, Inc. Publishers

A large and fully reusable space-launch system has not yet been realized — nearly all rockets and spaceships are single-use. So experts say it would be a game-changer in reducing the cost of access to space, not to mention reaching new destinations there.

"That allows us to effectively reset the rocket equation," Wooster said. "We go from getting 100 tons or more into low-Earth orbit, then refill, and we can take that payload pretty much anywhere — including the surface of Mars, the surface of the moon, or elsewhere."

An illustration of SpaceX's Big Falcon Spaceship landing on Mars. SpaceX

SpaceX is now shifting much of its staff and funding toward building the BFR, starting with prototyping the spaceship under a tent at the Port of Los Angeles.

Musk previously said the spaceship element of BFR is "by far the hardest" part of the system to get right. He also said he hopes SpaceX can build the first prototype by mid-2019 and start launching it on short "hop" tests at the company's rocket facility in South Texas.

Each BFR spaceship is also designed to be refilled with methane on Mars to power its return to Earth. SpaceX plans to manufacture that fuel using water from Martian soil, carbon dioxide in the planet's thin air, and electricity from solar panels.

Some of the new details Wooster revealed

A cutaway illustration showing the crew and cargo area of SpaceX's planned Big Falcon Rocket spaceship. Elon Musk/SpaceX

What, exactly, the first missions to Mars would try to accomplish remains uncertain, but Wooster filled in a few details.

He said the first two uncrewed cargo missions would "confirm the water resources in the locations that you're interested in, and then determine any [landing] hazards for future missions, and then start to put in place some of the infrastructure that you'll need," such as landing pads.

The two crewed ships that follow, plus two additional cargo ships, "would be really focused on getting the initial outposts set up, get going on all their resource work that will be needed to both provide propellant, along with expand the base for future activities there," Wooster added.

Each ship will carry "at least" 100 tons' worth of supplies, he said — about 100 times the mass of NASA's Mars Curiosity rover. This means all six ships' payload combined would weigh about 150%-200% the mass of the entire International Space Station — a football-field-size structure that's still being assembled two decades after its first piece launched into orbit.

Wooster suggested that this cargo overkill is about redundancy: By transporting far more supplies than any crew needs for a years-long Mars mission, along with bulky gear, SpaceX can circumvent a lot of advanced (and as-yet-non-existent) technologies that might otherwise be required to stay on Mars.

"We're minimizing the number of elements that we need to develop in order to make early missions happen," Wooster said. "As we go forward, there may be future efficiency improvements that we'll make, but we're very much focused on getting to Mars as quickly as possible and getting set up with robust surface presence there."

Wooster also said the first spaceships will likely serve as homes for astronauts. This may not be the most comfortable setup, but it could reduce mission complexity and development by skipping the need to immediately build Mars habitats.

"You'd be operating out of them using the various systems on them to support the activities there," Wooster said. "They'd be staying there indefinitely."

Eventually, however, Wooster said that bringing the spaceships and their crews back home will be necessary to recover costs. (One expert told Business Insider that SpaceX's BFR development program alone may exceed $5 billion.)

"As you move forward, to further reduce the cost, it is advantageous to be able to use those ships multiple times" on journeys to and from Mars, Wooster said.

An illustration from Paul Wooster's presentation on SpaceX's Mars mission plans. The Mars Society/YouTube

Finding and mining ice — perhaps as much as one metric tonne per day, according to a slide (above) that Wooster shared during his presentation — will be the prime goal of the first SpaceX Mars missions.

Refining it enough to be combined with carbon dioxide and converted into methane fuel will also be key, as will preparing the planet for future settlers.

"The idea would be to expand out, start off not just with an outpost, but grow into a larger base," Wooster said. "Not just a base like there are in Antarctica, but really a village, a town, growing into a city and then multiple cities on Mars."

Where SpaceX needs help

Some of the things Wooster said SpaceX needs help with indicate how far the company is from nailing down a mission plan that is doable and survivable.

Wooster's presentation showed that SpaceX has four possible landing sites picked out in northern Mars. These are locations where it may be cold enough for huge reserves of subsurface ice to exist, yet sunlight is strong enough for solar panels to gather ample energy.

However, Reddit user CapMSFC claims to have attended the talk and heard an impromptu question-and-answer session afterward, in which Wooster said SpaceX is working with staff at NASA's Jet Propulsion Laboratory to figure out which site is the best candidate. That evaluation is apparently primarily based on Mars Reconnaissance Orbiter images, since there is not yet an ice-scouting rover mission.

Wooster also said the company isn't yet sure how it will construct landing pads on Mars to ensure safer arrivals for future missions and would be happy to take ideas, according to CapMSFC.

A prototype of NASA's Z-2 spacesuit, which is designed for astronauts to explore planetary surfaces. NASA

Spacesuits that'd work on the surface of Mars are still an enigma, too, Wooster reportedly said. (Not even NASA has completed development on a suitable model.)

SpaceX's plans for protecting people from radiation in space and on Mars are not yet known either.

"There's also questions just about, 'What will people be doing there? How will they be living and working?'" Wooster said. He added that it'd be a great opportunity to answer profound scientific questions, such as whether life ever existed on Mars or still does.

"These types of things are really opportunities for pretty much anyone in the broader Mars-related community to engage in," Wooster said. "SpaceX is really focused on getting the transportation architecture set up and achieving that as quickly as we can. But it's really to enable all of these types of activities there as well. That should certainly encourage people who are able to contribute there to do so."

With about four years to go until its first mission — at least in theory — SpaceX has begun meeting formally with NASA staff, academics, and experts at other spaceflight companies to workshop the details behind its Mars landings missions.

Watch Wooster's full presentation on SpaceX's Mars plans