Putting humans on Mars has been a staple of science fiction and a goal of numerous scientists for decades. Today, thanks to technological advances, fascinating images sent back from the Red Planet by rovers and orbiters, and growing concerns about our future here on Earth, interest in putting boots in that red soil is at an all-time high.
NASA, SpaceX and Mars One are all aiming to land people on our neighboring planet in the next 15 years or so, each on their own timelines and using different architectures. Here's a look at all three road maps, starting with a plan from Iron Man himself, SpaceX founder Elon Musk.
SpaceX's secret sauce is its reusable rockets, which Elon Musk says bring down the cost of accessing space, and by extension, Mars. As of this writing, the company has successfully recovered 16 first stage Falcon 9 boosters and also successfully relaunched previously used rockets. The precision landing technology can also be used to land on other worlds.
Musk's long-term vision for Mars is audacious. He envisions huge transport ships delivering colonists over the next century to create a Martian metropolis of a million people. He's also proposed terraforming the planet, perhaps by using nuclear explosions to trigger climate change.
The key to the SpaceX Mars road map is what Musk calls the "BFR" (for "Big F***ing Rocket"), a vehicle he says can outperform some of the most powerful rockets ever made, including the Saturn V that took Apollo astronauts to the moon.
Musk says the BFR can haul 4,400 tons to Mars.
In September 2017, Musk unveiled a refined, slightly smaller design for the SpaceX Interplanetary Transport. The ship is massive even after it separates from its rocket boosters, with a payload eight stories tall, enough room to fit smaller rockets inside ... or a bunch of adventurous explorers.
A cross-section view of the BFR, minus the rocket boosters designed to separate and return to Earth for refueling after launch.
SpaceX built a development fuel tank to test ahead of building the BFR. Note the people below for scale.
When set up for a Mars flight, the Interplanetary Transport has room for 40 cabins for the long trip.
Musk says the BFR could also make trips to a lunar base.
Musk hopes to send his rockets to Mars within five years to start setting up infrastructure in preparation for the first people to visit, a few years later.
A rendering of a SpaceX rocket heating up on entry into the Martian atmosphere.
Musk says it should be possible to make Mars a "nice place to be." This could take some work, given all the ways to die there.
Though he offered few details on exactly how it will all come together, Musk did show this rendering of a potential future Mars colony during a speech at the International Astronautical Congress on Sept. 29.
NASA sees the long road to Mars in three phases. The first is underway right now with research on the International Space Station that wlll inform Mars missions in the future. Partnering with private Mars fanatics like Musk on missions closer to home is also part of the plan. But the most exciting work happening today is the development of the hardware to travel further in space.
Ferrying all the infrastructure and supplies needed to set up shop on Mars will require lots of firepower, and NASA's answer is the Space Launch System (SLS), its next-generation rocket designed with deep space missions in mind.
An Uber won't get you to Mars just yet. Fortunately, NASA has already been testing its new Orion crew capsule that could ride atop the Space Launch System to one day transport astronauts to the red planet.
NASA is soon to move into the second phase of the journey to Mars with missions to prove its deep space prowess a little closer to home.
NASA's planned Deep Space Gateway will be a small space station orbiting the moon, where crews can test technologies and prepare for future journeys to Mars.
Making the long journey to Mars while staying safe and healthy will require more than a space-worthy Winnebago. A deep space habitat has been tested under desert conditions here on Earth, and NASA hopes to launch such a habitat for missions to cislunar space in the next decade or so.
OSIRIS-REx is currently traveling to near-Earth asteroid Bennu on a sample return mission, designed in part to practice the type of robotic operations that will be useful for Mars.
The third phase of NASA's Martian road map involves getting further away from Earth and closer to boots in the red dirt.
The latest concept in living on Mars comes from Lockheed Martin, which has designed its Mars Base Camp as a kind of orbiting waypoint for Mars exploration. The Martian space station is designed to integrate with NASA's Orion and also with landing craft traveling to and from the surface.
Lockheed Martin's vision for a Mars surface lander is called the Mars Accent Descent Vehicle. The company says the craft could let astronauts explore the Red Planet's surface for two weeks at a time before they'd have to return to the Mars Base Camp.
Finally, the culmination of decades of research, development, training and prep-launches will be the landing of human astronauts on Mars to establish a research base. NASA's current timeline has the first landing happening in 2033 or later.
Finally, there's the dark horse in the race to the Red Planet. Mars One is the ever-morphing effort to turn space exploration into a reality show. The effort has struggled to meet its fund-raising goals and timeline targets, but it's still moving forward. A worldwide search has narrowed a huge candidate pool of possible astronauts down to 100 finalists set to compete for spaces on a future Mars mission. The current timeline has the first crew reaching the planet in 2032.
Mars One plans to contract with a third party like Lockheed Martin to supply its lander technology.
Mars One's plans have been met with criticism, but the plan for a small, permanent colony is still moving forward.
Original plans call for Mars One colonists to make a one-way trip, without the ability to return to Earth, ever.
One thing is constant in the quest for Mars: Timelines always seem to be getting pushed back. SpaceX and NASA both say they have the rocket technology to get us there. SpaceX hopes to get there sooner than NASA, but only NASA has tested the rocket it plans to use for the mission.
Still, the odds are on Elon Musk getting there first, according to one oddsmaker, that is. But as the saying goes, "space is hard," and Mars is far away, so it's tough to make predictions. It sure is fun to watch the race though.