45 thoughts on “Colonizing Mars”

  1. One mistake Zubrin and others make is making an ERV integral to the mission. Its a completely separate issue. Send it before any colonists and don’t replace it until used.

    It also makes sense to have different vehicles for different environments. Also fuel should be waiting in orbit for earth departure, not sent to follow.

    Thinking on this could be clarified by providing something to bring everything in focus. This is why I propose a $5m per ticket price not coming from the colonists. You can argue where does it come from but that misses my point.

    Let many, not just SpaceX, contribute to the architecture. A ship going from orbit to orbit has the least extreme requirements and the most options… many companies could produce such a thing if they were sold the engines (everything else could have a multitude of suppliers.) We will have vehicles to put people in orbit which goes down in cost simply by taking more people at a time. A mar’s SSTO lander is very doable. The transit vehicle can be made so robust it will still be in use 200 years from now (along with many other designs.)

    Zubrin is right about different fuels for different elements of the trip and transit duration. He’s absolutely right about 50 ton sizing. Any habitat we send to mars should be temporary backup though.

    1. If the objective is a proper colony, as opposed to a temporary outpost, any resources sent from Earth need to be viewed as temporary.

          1. Abundant if we have the right mindset which I see very little evidence. Why do we always think Apollo/Marxist/top down planning leads to success when it only works in narrowly defined settings?

            How is it that people that proclaim free enterprise don’t actually believe in it?

        1. Even the colonists would need to be replaced on a long enough timespan. 😉 But part of a successful colony is colonists producing their own replacements.

    1. The worth of an idea isn’t if a person has enough money to pull it off. Many people have great ideas all the time but not the means to see those ideas realized.

      There are five ingredients: time, money, people, technology and ideas.

      Lacking in any of these doesn’t mean an idea sucks, just that they don’t have all the ingredients at the right time to make their idea happen. There are also people with money and people who fail at implementing a good idea or who succeed at implementing a bad idea or have all of the right ingredients but act at the wrong time.

      Musk is fortunate enough to be alive at a time where there is a confluence of technological innovation to enable his creativity to take shape and he also happens to have the money to pay for the people and technology to make it happen.

      There is also a 100% chance that Musk’s Mars plans will change over time.

      1. Well put. There are what I think are a lot of good ideas out there but not enough money is going to them.

  2. I agree with Zubrin that the TSTO Elon presented looks pretty unsuitable for a Mars launcher scenario. It’s going to use a very complicated second stage (which he compares with the Shuttle) for everything from Earth departure, to Earth-Mars transit, and Mars landing. More complicated than necessary. Also a lot of performance will be lost this way. I think in the long term keeping the surface-to-orbit launchers tied to their planet (Earth/Mars) and using a cycler to transit would make a lot more economic sense. Plus I wouldn’t be surprised if it cost less to develop and certainly less to maintain.

  3. SpaceX is falling into the usual trap that you can cut costs by putting everything in the same vehicle. We have seen this in the F-111 and F-35 as well. The fact is vehicle airframe design and manufacturing is comparatively cheap vs engine design. Software can be repurposed. It’s better use different designs for vehicles on separate environments.

    1. But it’s critically important that the exercise equipment we send all the way to the surface of Mars be returned all the way to the surface of Earth, otherwise we could have an exercise equipment shortage on our home planet, and that would mean future astronauts would be flabby.

    2. At this point I’m thinking you may want 4 vehicles:
      – Earth shuttle.
      – Mars shuttle.
      – Passenger interplanetary transport.
      – Ion drive slow boat for cargo.

      1. Yes. Exactly right. The ion drive for cargo could push from LEO to LMO (or LLO for that matter) as well as from LEO to an EML staging point for that cargo / equipment / craft that would need to attend the passengers.

        So, my question is this. Could such a system be operated using Falcon Heavies (maybe with crossfeed & Raptor engines) instead of the BFR?

        1. An interplanetary ship that never makes planetfall could be assembled in orbit. A shuttle making short round trips could have much more compact passenger accommodations and make multiple trips while the interplanetary ship is in orbit. A Mars shuttle in this plan might be sized right for launch as an upper stage on a Falcon Heavy. All together, I expect the system could work without a rocket any bigger than the Falcon Heavy.

  4. Fundamental to the SpaceX Mars plan is large propellant generating capacity on Mars or the Martian moons.
    But such large propellant generating facilities would be much easier to do on the Moon, which would thus be used to produce *orbital* propellant depots.
    The argument has been made against this that it is wasteful to first land on the Moon to gas-up then take off for Mars. This is disingenuous because the idea is NOT to land the Mars-bound spacecraft on the Moon, but to refuel in *orbit*.
    The fascinating aspect of doing it this way is that *currently existing* rocket stages could be then used for the manned Mars missions, no giant ITS or even SLS rocket required.

    See :

    http://exoscientist.blogspot.com/2015/08/propellant-depots-for-interplanetary.html

    Bob Clark

    1. While advocating for any particular fuel station, economic reality must be primary. The question of the cheapest fuel to LEO or Lagrange is not one dimensional (even if it can be summed up in cost per kg.)

      At the moment, the infrastructure only supports earth as the source of fuel. All other potential sources (moon, mars, other rocks) require massive capital expenditures before they can begin to compete with earth.

      If we are going to mars, mars is the only place this spending is definitely going to happen. So even if moon fuel would be cheaper, the economics of incremental development suggests we will probably refuel in LEO from mars fuel before we build such infrastructure on the moon (especially if methane is the choice of fuel.)

      1. This also suggests a mars train made up of engine module, habitat module and fuel tanker module.

        The engine module takes the train back and forth between earth orbit and mars orbit. The habitat module goes full to mars but usually empty to earth. The tanker module goes mostly empty to mars and most full to earth.

        1. Each module could be separately upgraded and made by various competing companies just as train engines and cars are today. A train could consist of different company resources.

        2. The habitat module goes full to mars but usually empty to earth.

          Seems like they could find something to send back.

  5. This was an interesting article but I think the differences between Musk’s and Zubrin’s respective approaches are explained best by Musk’s pragmatism and Zubrin’s idealism.

    To Zubrin it is all about colonizing Mars. He assumes that most who go to Mars will want to stay and few will want to return. Thus it makes no sense to him to send a 100 person habitat to Mars just to bring it back.

    Musk is interested in colonizing Mars as well but his interest is tempered by realism. He strongly suspects that most who go to Mars will want to return to Earth so his architecture reflects that. If most people are coming back, the habitat has to come back with them.

    I think Musk has judged the reality better than Zubrin.

    1. Musk is making the same mistake with his mars architecture as his hyperloop. The difference is he can adapt. His strength is he will do something even if he has to change it later rather than viewgraph it to death.

      That monster rocket will probably be repurposed because getting cost/crew down can happen without it. The Falcon 5 served it’s purpose without ever being built.

      1. Yes he has shown the ability to change his architecture and his business plan very quickly as he goes along. That is a definite advantage. The thing is, in the past he was usually scaling the system up and upgrading it. This time I’m afraid he’ll have to make things smaller and simpler for them to be viable. As Linus once said regarding software it’s easier to make something bigger than to make something smaller. This rocket is just too damned big. Even SLS looks small in comparison.

        I’m kind of hoping this is just a PowerPoint exercise to see if people take the bait. Then again they did build that fuel tank even if it was just the second stage one. I hope he doesn’t believe his own propaganda.

    2. He assumes that most who go to Mars will want to stay and few will want to return. Thus it makes no sense to him to send a 100 person habitat to Mars just to bring it back.

      That’s a good point and even if people do want to stay on Mars, there will be those who only go there to work for a certain period of time or who go on a Mars vacation. But that doesn’t mean the tradeoff issues Zubrin raises shouldn’t be considered.

      To me, it looks like Musk wants to do it all on his own and he has little choice right now. SpaceX is a launch company, not spaceship company. The architecture that he put forward plays to SpaceX’s core competencies but if some other company creates a spaceship, maybe his architecture will change.

  6. Musk didn’t begin as a billionaire. His luck consisted of being born smart. Each of us with a better idea had the option to make it happen, especially people with the opportunities of Zubrin. Musk is the one who is doing it. Bezos, too. Space is hard. Talk is easy.

    1. The problem is that what is compelling varies from person to person. Few people care how other people spend their money but everyone thinks the federal budget should support what they think is a compelling cause. A significant portion of the population thinks no activity in space is worth the cost.

      What really matters is what Musk and other people engaging in space based activities think is compelling, since its mostly their money and effort being expended. As the barriers come down, more people can pursue interests they think are compelling but since future activities in a unknown environment can’t be reliably predicted, we don’t know what these compelling reasons are yet or if they will materialize.

      1. The visionaries supply seed money. This can get things started. But Mars will be colonized, and the colony sustained, only if it makes economic sense. Communities that lose their economic basis die out.

        I don’t believe in Musk’s Mars plan. It makes no sense to me, and I don’t see how it can succeed. At best, the cost reductions he is driving will enable other activities in space that make more sense. These will likely be in cis-lunar space.

        Eventually, colonizing Mars may make more sense, in that great unknowable long term future. But to the extent they are unknowable such futures provide little justification for actions in the present.

  7. The only reason I’ve ever heard that auctioning off mars real estate to pay for transportation costs will not work is because people would lack confidence in their title.

    Why don’t we fix that?

    Mars real estate would pay the entire cost for at least the first million people. Those people would arrive without debt and rich.

    To get passage paid in full they would all have to agree to protect and defend the ownership title of others that paid for their passage.

    1. Colonists contracting to stake claims on behalf of their sponsors … might work, if the sponsors expect the value of the claims to rise sufficiently. Unless transport costs go way down that seems dubious. As they say in real estate, location, location, location.

      1. Thanks for using actual reason Peter. Who are the sponsors? Regular people buying essentially a novelty for any of their own reasons. We don’t need to care why they would spend $5 a hectare (which is just a minimum bid. $1/(1/5th hectare plots) Locations near occupied sites would naturally demand higher bids.) All plots don’t need to be sold immediately either.

        Transport cost will start much above my $5m/crew maximum ticket price, so initially would only reduce costs rather than provide a profit, but that price is within near term reach and not just by SpaceX. As other companies compete that ticket price could approach the SpaceX goal which means multiple companies all operating for normal profit.

        How fast will land prices rise? That’s what gives the biggest win. Because the land prices are so low to start even a few penny increase represents a huge percentage profit.

        People already pay $20 for worthless novelty deeds. Actual title could be resold for 400% profit or more almost immediately. If we believe and defend the concept of ownership.

        It’s understandable that people don’t get this because people don’t own real estate anywhere here on earth. You don’t actually own anything that can be taxed and regulated away from you. Ask any economist. At best you are part owner. But you can ignore this last paragraph rant.

        1. Land claims in the American West were based, ethically, on developing or working the land. Or pragmatically on occupation and running off counter claims. There is also established law for declaring neglected property abandoned and available for a new claim, even absent property taxes. How much Martian land are you expecting each colonist to develop, work, and/or occupy?

      2. About the value of claims: The mars settlement initiative uses $100/acre for their speculation. I’m using $2 per acre while considering $20/acre to be in the impulse buy sweet spot. I believe this is more than reasonable since others have argued you could get much more. The point is you don’t need more for this to finance everything.

        What if a single person or group buys up most of mars? That’s fine too. It still pays the ticket prices and that person/group takes the profit risk. That’s prevented because nobody is rich enough to buy it all. Plus we don’t auction plots bigger than a square kilometer at a time ($1 minimum bid per 2000 sq. meters. $500 minimum/sq.km.)

        Location. Location. Location. …will continue to be true (keeping in mind this is dynamic, not static. More colonists over time guarantees average land value appreciation.)

    2. Mars real estate would pay the entire cost for at least the first million people.

      You would have been right at home at the Q & A after Musk’s presentation, Ken. 🙂

      1. JD, I can handle the insult. Can you handle an actual argument?

        Does mars real estate now or will it ever have value?

        Just think about that and consider the implications.

        1. JD, I can handle the insult.

          No insult intended, Ken. Sorry if it came out that way.

          Can you handle an actual argument?

          If you’ll make an actual argument instead of a declaration. When you do make an argument, it isn’t really an argument, just an arithmetic exercise like “If I had a nickel for every square foot on Mars I could…”

          Does mars real estate now or will it ever have value?

          Those are the questions you’re supposed to be answering, Ken. You’re the one claiming selling Mars will lead to great things. Do something to make that claim plausible. Put a few acres on eBay and let us know what they go for. There are people selling extraterrestrial real estate right now. I’m sure they’re making a good living at it but I haven’t heard that they’re becoming fabulously wealthy. Maybe you’ll do better. But the point is no one is just going to take your word for all this.

          I note that stealing underpants made Musk’s list of potential funding sources. Selling Martian real estate did not.

    3. The only way to have confidence in a title is if a government stands behind it. Not sure if the US could guarantee them because of the Outer Space Treaty.

      1. From a pragmatic standpoint the colonists would constitute the government over the land occupied by the colony and the relevant legal authority over land claims in the immediate vicinity … at least until someone came along and ran them off.

  8. SpaceX’s plan doesn’t have enough delta-V in the propellant budget for mars-transfer to mars orbit. It depends on aerobraking away all the interplanetary excess velocity + the 5 km/sec from falling into Mars’s gravity well.

    I suppose on the return trip, it would depend on aerobraking away all Earth-transfer to Earth excess + 11 km/sec on returning to Earth.

    I’d like a plan with orbit-to-orbit ships and orbital propellant depots myself. While it might be more complicated and require more vehicles, it would also be more flexible and have more margin for error (and would allow entry and landing at much lower speeds).

  9. Mr. Simberg, you were right about the apollo mentality. Mr. Zubrin doesn’t grasp the concept of spacex; re-usable. I don’t live in a Boeing 737, but I sometimes travel in one. My house was built in the U.S., not brought over on a ship from Europe. After all the changes he will come up with, Spacex’s mission will be 5, 6, or 7 astronauts in low earth orbit supplied by Chinese, Russian, or North Korean rockets because ours will not be man-rated yet.

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