In a tweet, SpaceX suggested that multiple Dragon spacecraft would be sent to Mars starting in just two years, flying aboard the company’s as-yet untested Falcon Heavy rocket. Those spacecraft would then inform future missions, or the “overall Mars architecture” as it’s referred to in the tweet.

https://twitter.com/SpaceX/status/725351354537906176

The Red Dragon is a modified version of the robotic Dragon spacecraft that SpaceX uses to ferry cargo to and from the International Space Station for NASA. Packing eight SuperDraco thrusters, the spacecraft can maneuver itself to a landing on solid ground by firing those thrusters as retro-rockets, slowing the capsule’s descent and placing it softly on the planet’s surface.

SpaceX has shown a certain deftness at so-called propulsive landings. It’s the same concept that the company has now used to land its Falcon 9 first stage rocket boosters at Cape Canaveral and on its floating drone ship at sea. But in landing the Red Dragon on Mars, SpaceX would be wandering into territory even NASA has yet to chart. NASA’s Curiosity rover weighted roughly 2,000 pounds and required a complicated landing vehicle known as the “sky crane” to slow the rover’s descent and then gently lower it to the Martian surface. The Red Dragon would reportedly weigh ten times more.

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The missions would also mark the first commercial flight to Mars and the first commercial object to touch down there. While there’s no word yet on what kind of payload would travel aboard the Red Dragon, presumably there would be plenty of room not only for instruments and sensors to take measurements of the Martian environment, but perhaps even ground robots like NASA’s Mars rovers that could explore the terrain there.

The idea, ostensibly, would be to send several unmanned missions ahead of any manned mission, using the early Red Dragon missions to seed the planet with equipment that later human visitors could use to assemble a habitat there. Naturally, there’s a whole lot of work that has to be done beforehand—and that’s before SpaceX can even start thinking about life support systems.

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For one, SpaceX has yet to fly its Falcon Heavy rocket, the larger, more powerful version of its workhorse Falcon 9. The Falcon Heavy’s first flight is slated for November of this year, and—this being rocket science—it’s reasonable to assume such a huge rocket might experience a delay or two before all the kinks are ironed out.

SpaceX will also have to demonstrate that the Red Dragon can actually land on the Martian surface. In tests, SpaceX has used its SuperDraco thrusters to hover a Dragon spacecraft as well as to propel one skyward during launch pad abort tests. But the spacecraft has never drilled on propulsive landing. SpaceX plans to test the technique on a future Dragon capsule returning from a mission to the International Space Station.

SpaceX’s tendency to set ambitious timelines represents part of the company’s character, and whether it launches to Mars in 2018 or not is perhaps less important than the fact that SpaceX has a goal in sight. For more than a decade, NASA has talked about sending a manned mission to Mars at some vague point in the future, likely in the 2030s. Perhaps the big takeaway from today’s announcement is that as of 2016, SpaceX seems a lot closer to putting humans on Mars than NASA ever has.