SpaceX's desire to put humans on Mars is nothing new; the company was founded with that goal in mind. But now, the company is testing early versions of the spacecraft it envisions using on such journeys, evaluating potential landing sites and thinking through what a long-term base on the Red Planet might look like many years from now.
"In terms of the vision that we're moving toward, it's really to enable cities on Mars and everything that comes with having a city, having a large and growing population," Paul Wooster, principal Mars development engineer at SpaceX, said during a May 20 meeting of the Committee on Space Research (COSPAR) focused on human missions to Mars.
"This obviously is a very significant endeavor, something that will take many years, many decades even, to really achieve," he said. But the company is targeting a characteristically ambitious timeline of perhaps 2022 for the first uncrewed missions to Mars, Wooster said.
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The vehicle that the company envisions as the workhorse for such a city is the Starship, powered by the Super Heavy booster. The pair is still in development, with SpaceX conducting early tests on a string of Starship prototypes at its site in Texas. No full-size prototype has left the ground yet.
While Wooster said that Super Heavy will be essentially a scaled-up version of the reusable boosters that power the company's Falcon 9 and Falcon Heavy rockets, prototypes of the massive booster have not yet been displayed publicly.
Nevertheless, Wooster said, SpaceX hopes the pair will come together rapidly enough that the company could consider launching the first uncrewed test missions to Mars during the 2022 window of opportunity. (Mars aligns with Earth favorably for spacecraft missions every 26 months; the upcoming window, in late July and early August 2020, may see three different robotic missions launch to the Red Planet.)
Whatever the timeline of SpaceX's Mars program, here's what the company is envisioning: The Mars journeys would rely on fuel depots stationed in Earth orbit. A Super Heavy booster would launch an individual Mars-bound Starship to Earth orbit, where it would rendezvous with a previously launched Starship full of fuel, which would then pass along that propellant.
Next, the Starship would head to Mars, belly flopping through the atmosphere protected by heat-resistant shielding until it ultimately lands upright. Two or more cargo Starships would launch during the first Mars window.
If this initial batch of flights went smoothly, a crewed Starship could follow, accompanied by more freighters. Although the Starship is discussed as holding 100 people, early missions would likely carry much smaller crews to leave more room for cargo necessary for setting up camp on the Red Planet, Wooster said. SpaceX is hoping to trim the Mars journey to below six months long — perhaps even as short as four months — in order to reduce the radiation that humans would be exposed to during the journey.
As crewed missions arrive on the surface, the first priority would be scouting and processing local supplies. Starships are designed to run on liquid methane-oxygen fuel, Wooster said, in part because of the low cost of those ingredients on Earth but also because scientists believe they can be produced on Mars. Among the first tasks for Starship missions would be mapping the availability and accessibility of the raw materials for that fuel, so humans would have a way to get back home to Earth.
Resources also shape where the company wants to land. SpaceX is focused on two potential sites, Wooster said, one near Arcadia Planitia and Erebus Montes and the other near Phlegra Montes. Both meet some key criteria: They are in the middle swath of the planet where it's easier to land and they're at lower elevations, so the thicker atmosphere will do more of the work to slow an incoming spacecraft.
And, of course, there seems to be lots of ice nearby. "We're very much focusing this landing-site identification effort toward areas that have very significant quantities of water ice," Wooster said. "That's a very critical resource."
Next will come basic infrastructure like landing pads, habitats, power-generation systems, radiation shelters and greenhouses, Wooster said, although he emphasized that SpaceX is focused on transportation and leaving the development of other pieces to other organizations.
Once a final site is selected and missions begin, Wooster said that he thinks SpaceX might find itself with a little deja vu from its experience developing its Starship testing site near Boca Chica in South Texas. Though residents who lived in the beach community long before SpaceX came to town and have since fended off buyout offers and nearby explosions might disagree.
"This site was very undeveloped when we came in," Wooster said, "so I think we've also been going through a lot of the same types of things as you might eventually experience on Mars in terms of having to set up infrastructure, although obviously a lot easier in terms of having air and such available to you."
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