Colonizing Mars the SpaceX way

Living on Mars might not be so far off in the future if Elon Musk has any say.
Wikimedia Commons/ NASA Ames Research Center

OK, so who is ready to go live on Mars? I saw a few hands go up there in the Boulder Weekly readership. Now multiply that across the globe and you’ll have more than enough people to fill up one of Elon Musk’s proposed “Interplanetary Crew Transport” (ICT) vehicles, the primary component of his Interplanetary Transport System (ITS). Now, what the heck is that?

On Sept. 26 at the International Astronautical Congress in Guadalajara, Mexico, Elon Musk, the billionaire entrepreneur behind SpaceX and Tesla Motors, laid out his plans for sending, not just a few people, not just hundreds, but thousands and ultimately tens of thousands of people to the Red Planet. OK. So, one, just what is Elon Musk’s plan? And two, will it work?

Musk’s ITS plans involve building a fleet of the ICT spaceships. Each of which would be able to carry 450 tons of passengers and cargo to Mars.

Each of these craft would be the second stage of a new massive launch system. They would be launched into Earth orbit atop an enormous first stage booster rocket, larger than the Saturn 5 that launched the Apollo astronauts to the moon in the late 1960s and early ’70s. For purposes of comparison, the Saturn 5 weighed 3,039 tons at launch, the new ICT/booster stack would weigh 10,500 tons. The ICT spaceships would refuel in Earth orbit and then launch to Mars with a prodigious fuel burn that would act to shorten the trip to Mars from the standard six to eight months that current robotic missions take to just three months.

Keep in mind that traveling to Mars isn’t like driving from Chicago to Los Angeles. Well, it might be if both Chicago and LA were orbiting around St. Louis.

With Earth and Mars orbiting around the sun, traveling from one planet to another involves launching at the right time so that Mars (or the Earth if traveling in the reverse direction) is actually there once the spacecraft reaches its orbital distance from the sun.

But back to the Musk/SpaceX plan. The ICT would arrive at Mars and actually be capable of landing on the surface where it would refuel (using propellant derived from the Martian atmosphere and water in the near surface), and head back to Earth orbit to collect another set of passengers and cargo. Musk’s current plans don’t address major issues such as the radiation hazards of the interplanetary flight to Mars, or how the colonists would survive on the harsh surface of Mars.

To get a better idea of the viability of the Musk/SpaceX plan, I spoke with Dr. Robert Zubrin, president of Pioneer Astronautics of Lakewood, Colorado and the originator of one of the most widely celebrated Mars mission architectures, the Mars Direct concept (a mission profile that revolutionized thought about how Mars could be reached using largely existing technology and at a reasonable cost). Zubrin has some complimentary things to say about Elon Musk’s plans as well as some pointed criticisms.

Zubrin praises the approach that Elon Musk’s SpaceX Corporation has already taken to try to re-use the first stages of their now-operational Falcon 9 rockets. Zubrin says the successfully demonstrated approach of having the Falcon 9 first stages return to land on Earth tail-first under controlled rocket thrust will be adaptable to land SpaceX ICT rockets on Mars. Indeed, SpaceX plans to launch one of their Dragon crew capsules to Mars sans the crew, but with its descent rocket assembly in place in 2020 in order to test land a heavy payload (up to 7 and a half tons) on Mars. If successful, the landing of the “Red Dragon” spacecraft would mark the landing of the heaviest ever spacecraft on the Martian surface.

However, Zubrin says, “the real problem of the Musk approach is that it is vision-driven, not mission driven.” He sees the development of the ICT as an interplanetary spaceship as more of a goal than the actual mission of colonizing Mars. Moreover, he says that the use of a giant second stage and burning massive amounts of fuel to shorten the travel time is a detriment, since it reduces the amount of payload that can be taken to Mars by approximately three times. Also, Zubrin notes that by taking the ICT second stage to and from Mars, the Mars colonists would be losing potential living space. After all, “the people will need someplace to live once they get there,” he says, and the Musk plan is short on those details.

A better approach in Zubrin’s opinion is to “get out of the giant-interplanetary-spaceship-thought mode” and focus instead on sending “usable cargo instead of giant rockets” to Mars. Capitalize instead on the attractive parts of the plan — use the orbital refueling approach touted by Musk and utilize a soon-to-be-ready rocket, the SpaceX Falcon Heavy booster. The Falcon Heavy will be able to lift 54 tons to Earth orbit. By using on-orbit refueling, and a reusable orbital booster, much of that 54 tons could be sent directly to Mars where it would prove invaluable to any Mars colonists.

While the Interplanetary Transportation System plan of Elon Musk might seem incredible today, the thought of giant ocean liners crossing the Atlantic Ocean, let alone jumbo jet airliners, would have seemed incredible to the people of Europe at the time of Columbus. There is value in dreaming big dreams. To quote the poet Robert Browning, “Ah, but a man’s reach should exceed his grasp, Or what’s a heaven for?”

Bill Farrand is a Senior Research Scientist at Space Science Institute in Boulder. He is a Science Team Member on the Mars Exploration Rover mission and is a Boulder-area rock climber. He has a blog on space-related matters at

  • Matt Akers

    Lets remember that “vision-driven” over “mission-driven” is single handedly inciting another space race. I am tired of “mission-driven”…atleast how the major players are doing it now. Let’s get something done. Let’s go to the Moon. Let’s go to Mars. And lets do it already. My cell phone has more power than an apollo capsule, yet they succeeded. We literally don’t have an excuse aside from being lazy and bureaucratic as a country. GO ELON GO! By the time you’re ready somebody will have figured out the radiation problem! People are going to die going to Mars. People are going to die going to the Moon. People died traveling to the Americas. Boats got better. So will space ships.

    • Anders tn

      In a way you can argue that Musk with his vision driven approach is doing the exact same thing Kennedy did. After all when Kennedy launched his “man to the moon” project the only mission parameter fixed in stone was get a man to the moon. The details of the trip and indeed none of the gear was designed by that point. So he didn’t really launch a mission so much as he launched a vision.

  • SonOfTheIsles

    Musk will never get to Mars.

    The same propeller heads that want him to go also believe that NASA never went to the Moon.

    Any success Musk has will be received with the same disbelief therefore in the minds of his groupies he can never get to Mars.

  • Anders tn

    To be honest I think they should build two different versions of the ICT. One which is return trip capable and one cargo vessel designed for a one way trip. The latter should maximise cargo capacity and be easy to dis-assemble. That way the spent rocket husk can be used for building structures on the martian surface once the cargo had been stored. I don’t think wasting time using the Falcon Heavy as the main launch vehicle for the cargo runner task would be beneficial. As for sending people with it I don’t think that serves any purpose. The purpose of sending 100 at a time is after all rapid growth of the colony. The rapid growth is again a means of avoiding the pitfalls you would get with an astronaut first approach. If you have a 100 civilians you don’t need to train everyone to do 2-3 crucial tasks. Hence if we assume even a horrible mortality rate simply sending a ship each year will keep the colony going. While I would prefer to send people to a ready built colony I simply don’t see that happening. For the first colonists going to Mars will certainly be a life shortening experience.