This is Elon Musk's plan to colonize Mars

Destination: Mars

SpaceX CEO Elon Musk has finally revealed his grand plan for humans to colonize Mars. He held court at the International Astronautical Conference in Mexico earlier today, walking through his plans for the logistics of getting to the Red Planet.

But why go to Mars? "There are two fundamental paths: we stay on Earth forever and there will be a mass extinction event. Or we become a multi-planet species," explained Musk.

Musk has long advocated for sending humans to Mars, and today's conference showed that he's getting serious about it now. On Sunday, SpaceX showed off its new Raptor engines that will be used on the company's Mars Colonial Transporter. The Raptor engines will be "several times" more powerful than the Merlin engines currently used by SpaceX to transport satellites and spacecraft into orbit.

SpaceX still intends to send an unmanned capsule to Mars by 2018, with plans to send humans there by 2024.

How humans will get to Mars

Elon Musk on stage

Musk's plans, as you can imagine, are extremely complex, but basically boil down to this:

A rocket using 42 Raptor engines will propel a spaceship into orbit. The whole system is called the Interplanetary Transport System (ITS). The booster will then separate from the ITS, at which point it will land back on Earth to be reused. The spaceship, meanwhile, will remain in Earth's orbit.

Using the same booster, a second fuel tanker will be launched to meet the orbiting ITS. After fueling up completely, the ITS will depart on its journey to Mars. With the aid of solar sails, the spaceship will arrive on Mars in 80 to 150 days, depending on the time of year. Musk hopes to eventually cut that transport time down to 30 days.

"This isn't what it might look like - this is what we plan to make it look like," said Musk of the plans.

But how will people come back, you ask? Musk hopes the first colonizers of Mars will be able to begin manufacturing fuel to get back to Earth. Mars is rich with resources that would make it possible to create methane-based fuel. Leaving Earth without enough fuel to return is a necessity, as it would require five times the payload to get the ITS off the ground.

SpaceX Mars colonization overview

Each Mars-bound spaceship can carry 100 or more people, making colonization somewhat affordable. With today's current technology and methodology, it would cost $10 billion to send one person to Mars. Musk's plan will cut that down to roughly $200,000 per person.

"Ultimately, we can get the cost down to about $100,000," said Musk. The plan to lower the cost to get to Mars boils down to reusable parts. Musk said each booster can be used 1,000 times, each tanker 100 times and each spaceship 12 times.

Interplanetary Transport System solar sail

The Interplanetary Transport System will use solar sails to aid propulsion

SpaceX has successfully landed and reused its Falcon 9 rockets in the past, but recently had an unexpected explosion during a rocket's pre-flight checks. The explosion is still under investigation, but was a huge setback for both SpaceX as well as Facebook, which planned to use the rocket to launch a satellite into space to provide internet access to Sub-Saharan Africa. Musk didn't address the explosion today, but there's still work to be done before SpaceX can attempt to send its first rocket to Mars.

A dangerous journey

ITS orbital refueling

Although Musk's plans are impressively detailed, they're just concepts at the moment. SpaceX built a fuel tank for the ITS already, but we're many years away from the inaugural odyssey.

"I think the first journeys to Mars will be very dangerous," said Musk when asked who would be the first Martian explorers. "Are you prepared to die? If you are, you can be a candidate for going."

Mars entry

Being there first isn't what excites Musk. "It's less about who goes first," he said. "What matters is making a self-sustaining civilization on Mars. It's minimizing existential risk and having a tremendous sense of adventure." Musk remains realistic about the amount of time needed to create a self-sustaining Mars colony, saying it could take 40 to 100 years.

One of the biggest challenges of colonizing Mars is getting the people to care. "I want to encourage the international community to build interplanetary spacecraft," said Musk. "The more, the better. Anything that improves the probability of the future is good."

Hisotry of SpaceX

Musk discussed the history and challenges SpaceX has faced

Musk also thinks the entertainment industry will play a big factor in fostering excitement for Mars colonization. "You really want to create the dream of Mars in people's minds. It's the new frontier," said Musk. "This is where the entertainment industry can play a role in putting the dream in people's heads. There's no physical frontier on Earth any more. Space is now that frontier."

NASA is currently one of SpaceX's biggest partners. SpaceX rockets are used to regularly resupply the International Space Station and it was NASA that was responsible for SpaceX's initial funding. NASA is currently working on its own plans for getting humans to Mars by 2030. Musk took time during today's presentation to thank NASA for its faith in SpaceX, but didn't reveal if the two were collaborating on bringing Musk's vision to fruition.

A long ways away

Although Musk's plans for Mars colonization are theoretically possible, it remains to be seen if the plan will actually work in practice. One of the biggest challenges is convincing the public that it's worth the risk to go to Mars.

As Musk reiterated, space travel is extremely dangerous, and it will likely take many years for SpaceX to hammer out all of the logistics and unforseen circumstances of commercial space flight.

ITS fuel tank scale

This is the ITS's fuel tank

There are still many unknowns, like how radiation will affect passengers aboard the ITS and how much training humans will need to be able to withstand the forces of takeoff and landing. Musk was dismissive about the requirements for training, saying, "You'll probably need a few days of training. You can train more if you want."

It was impossible not to be excited by the concept of colonizing Mars. Musk's ultimate goal is to see his grand plan actually work. "I'm personally accumulating assets just to fund this," he revealed, though it'll take a lot more funding from both private and public organizations to make Musk's dreams a reality.