47 thoughts on “Elon’s Mars Plans”

  1. The article does mention that:

    “Mr. Musk noted the future propellent they would use for their plans of Mars colonization would be liquid methane with liquid oxygen.

    This was in related to the fact it could be sourced from Mars…”

    Are there any private payloads that require a Falcon X-class launcher, or is the idea that SpaceX will bootstrap the business with NASA launches once SLS inevitably falls by the wayside?

    1. Are there any private payloads that require a Falcon X-class launcher, or is the idea that SpaceX will bootstrap the business with NASA launches once SLS inevitably falls by the wayside?

      About the only private payload that large that I can think of is one or more large Bigelow modules. Back in 2011, they had a model of a 2100 cubic meter space station model on display at the Space Symposium in Colorado Springs. It’d take something pretty hefty to launch one of those. If you have a powerful enough booster with enough volumne inside the payload fairing, (Falcon Heavy, perhaps), you might be able to launch more than one BA330 modules in a single launch.

    2. I can see two kinds of payloads. Space stations and orbital reconnaissance platforms. The bigger the mirror the clearer the picture.

    3. Are there any private payloads that require a Falcon X-class launcher

      Serious ones? I doubt it. Others have mentioned Bigelow’s 2100 m^3 system, but I’d have an easier time believing that’ll ever fly, or that there will really be commercial demand for it, if Bigelow had actually made any progress since Genesis 1 & 2. Or if they had at least made progress on signing any customers for their smaller modules. Can Bigelow eventually get there? Maybe–it’s definitely possible. But should people put a high probability weighting on Bigelow’s success? I’m not convinced.

      ~Jon

  2. That is tangentially mentioned in the article:
    This was in related to the fact it could be sourced from Mars, was easier to store and handle than liquid hydrogen and at just a 27% more volumetric than the RP-1/LOX combination, the tank and T/W of the engine could be kept at optimal sizes. He also stated that they would start using the staged combustion engine cycle.
    I know there are a lot of people proposing the use of methane. The Russians have a staged combustion methane engine i.e. the RD-0162. French CNES had a joint project with the Russians to develop the Volga engine using technology using cycle for the ESA FLPP at one point. IIRC the Japanese also had a project to use LOX/LCH4 for propulsion but IIRC the engine used a gas generator cycle.
    ESA at one point declared this was a requirement for future space missions, especially missions which required the use of propellant depots, because LOX/LCH4 can be stored at roughly the same temperature so you can use a common bulkhead. Also since the boiling point of LCH4 is higher than that of LH2 you would have less issues with long term storage as well.
    The problems I keep hearing about LCH4 are:
    – LNG is not pure LCH4. It usually has contaminants and quite often these are not well specced like liquid fuels or LH2. This leads to all sorts of engine design issues to the point where you may feel like you would have been better off going with LOX/Kerosene. i.e. you will still have polymerization issues because of contaminants and worst of all the amount of contaminants is highly variable.
    – LCH4 lies somewhere between Kerosene and LH2 in terms of density per mass and density per volume. Since it is cryogenic the fuel tanks will be heavier than Kerosene tanks. Since it is lower density you will need larger tanks with more surface area than Kerosene as well. It is useful to mention the propellant densities: LOX 1.140 g/cc, Kerosene 0.806 g/cc, LCH4 0.424 g/cc, LH2 0.071 g/cc.

    The more I read the literature the more I am convinced the optimum is LOX/Kerosene on 1st stages and LOX/LH2 in 2nd stages. LOX/LCH4 seems like a good idea on paper but it has not gained a lot of traction. The usual solution seems to be to run LOX/LH2 engines on a more oxidizer rich mixture or have variable mixture ratio engines rather than bothering to go the LCH4 route.

    Has anyone ever designed a LOX/LH2 or LOX/LCH4 1st stage engine in a launch system which does not use solids in parallel staging?

    1. “The more I read the literature the more I am convinced the optimum is LOX/Kerosene on 1st stages and LOX/LH2 in 2nd stages.”

      You seem to make the common mistake of just going for optimum performance versus optimum cost. People keep forgetting this essential fact: If your vehicle is so darn effiecient but so expensive that you can’t go anywhere with it, what have you gained?

      Using the same propellant for both stages simplifies things, lowering costs. LCH4 costs less, useful if you plan a reusable vehicle.

      “LOX/LCH4 seems like a good idea on paper but it has not gained a lot of traction.”

      Looks like someone is about to give it a shot.

    2. I have a hunch that what makes methane shine is full-flow staged combustion. That would be tough to do with kerosene, because of coking. Other light hydrocarbons probably don’t coke and would offer higher densities than methane but suffer from lower mass-specific heats, making them less attractive for staged combustion.

  3. Has anyone ever designed a LOX/LH2 or LOX/LCH4 1st stage engine in a launch system which does not use solids in parallel staging?

    Nevermind. I remembered. Delta IV Heavy.

  4. The postulated launch vehicle in that article… Wow.

    A single core, 9 engines on the first stage, one on the second, sounds like F9. Sounds a lot like F9R, actually. A scaled-up one.

    Sure, different fuel and engines, but there are architectural similarities.

    It’s the size that made my jaw drop. A 33ft diameter! For comparison, F9 is 12 feet. 33 feet was the diameter of the Saturn 5 first stage.

    Mass? It’s big. Very big. Nominal launch thrust looks to be about 9 million lb/ft. For comparison, Saturn 5 was 7.6 million.

    And that’s the single core version! They’re apparently looking at a FH style 3 core with crossfeed, with 27 million pounds of thrust. And fully reusable.

    I know thrust is a poor metric for launch systems, but… that’s a lot.

    I wonder where they’d launch such a beast from? That’s well beyond the capacity of any existing pad. I’m guessing they’ll stick with horizontal assembly, but even so, that’d take one heck of an erector. (It’d make Energia’s look small)

    I think it’s fairly obvious that for this scale of vehicle to be even thought about, they must have an economic model in mind. I think it’s pretty clear that Mars would not be the primary function of such a behemoth, but rather an ancillary capability. The single core, for example, would have a commercial application even in today’s market; launching multiple satellites to GEO in full reusable mode. The launch system will thus be primarily a profit maker – which I think is the only sensible way for a company to do it.

    2. The challenge with launching multiple GEO satellites is getting all of the payloads ready to go at the same time. They already running into this from time to time with the Ariane V and it only carries two satellites. Imagine trying to get ten or more ready to launch at the same time. With full reusability, a booster like this might change the economics of power satellites into something workable.

  5. This won’t ever get built.

    It’s a real shame that SpaceX seems to have moved beyond plans to use affordable heavy lift, like the Falcon 9, and fallen into the Apollo cargo cult mindset.

    1. It is not a bad idea to put such plans on paper. If the market does not materialize it simply does not happen that is all. I remember Elon claiming in the past that he wanted to replace the 9 engines in a Falcon 9 with a single engine. That is what you probably will see happening first if such an engine gets into production. This is more or less what Zenit does with the RD-171. Zenit launches are cheap and the reliability of rockets with a single engine is usually pretty good.

      Fact is system costs usually increase with system complexity, not mass, and one engine has less parts than nine.

      There is a lot of work done regarding reusability of staged combustion engines. I have little doubts they can be made reusable enough to fit their long term business strategy.

    2. Oh and none of the Apollo rockets ever used staged combustion or LOX/Methane. I have no idea why you think this is an Apollo cargo cult mindset. They are carving their own path here.

      1. The Apollo cargo cult is: get the President to declare a nation goal, build a really big rocket, ticker tape parades to follow.

        SpaceX is planning for step 2, you’ll soon see them calling for step 1.

        1. To me it is slavishly following Apollo program design decisions even if they make no sense today. For example because of the sense of urgency, with the time limited goal imposed by Kennedy, there simply was no time to do things like propellant depots. Another issue they had at that time was that automated control systems were rudimentary at best. Docking was perceived to be dangerous as heck and pumping cryogenic fuel even more so. Hence the need for the huge rocket. Heck even the Saturn V was a downscale from the original proposal of direct ascent using a Nova class launch vehicle.

          We have people today slavishly following every single aspect of the Apollo program in SLS. Same capsule shape. Same capsule heat shield material. Solid rocket tractor erection. Heck someone has even actually proposed to reverse engineer and manufacture the F-1 engines. Other people are already in the process of reverse engineering the J-2 engine. If that isn’t cargo cult engineering I don’t know what is.

        2. What you are describing is what we derisively used to call a ‘flag and footprints’ mission. For some back then this was a reminiscence of the Age of Discovery when people used to do things like that. So it was considered to be the symbol of the conquest of a New World. Of course no one actually bothered remembering we did the same thing in Antarctica in the XIXth century and it hasn’t turned into a hub of progress either. Antarctica actually has gravity, air, and water. It did not help that Antarctica had no population to speak of despite being a whole continent.

        3. I don’t see there is any way for NASA to pay for this heavy lift rocket for Elon. NASA is too closely wedded to the SLS.
          I still don’t see how Elon gets the financing for this billion dollar rocket.

          Bob Clark

          1. Seriously? Have you checked Elon’s personal net worth lately? Silly question; you obviously haven’t. For the record it’s ca. 10 billion dollars. That’s ten with a T and billion with a B. Elon can personally finance a mere billion dollar project any time he wants by doing the equivalent of checking under his own couch cushions.

    4. Trent, Did I miss the memo about SpaceX cancelling F9/FH?

      Yes, the size of this is overkill. But it may be if you want EVEN MORE affordable heavy lift than FH. Something on this scale could be fully reusable for FH class payloads. I don’t think they would contemplate it if they though that it wouldn’t lower costs eventually.

    5. This won’t ever get built.

      It’s a real shame that SpaceX seems to have moved beyond plans to use affordable heavy lift, like the Falcon 9, and fallen into the Apollo cargo cult mindset.

      I agree, *if* it doesn’t beat other systems (including their own) in cost per pound to LEO and GTO. However, it’s supposed to be fully reusable though, which would seem to allow for lower cost per pound.

      Given SpaceX’s design philosophy up through FH, I can’t see them suddenly choosing to ignore cost per pound.

      There’s also the fact that with a reusable vehicle, methane makes sense; fuel purchase becomes a substantial part of launch cost, and methane is a lot cheaper than RP-1.

    6. The single-core version isn’t Apollo on Steroids, it is STS minus wings on Steroids.

      Lets hope Elon can get the support requirements low enough and the robustness and flight rate high enough to make it work.

      Before he can start dropping Colonists on Mars, there are a lot of prospecting and prep missions to be done first. I suspect the single-core will fill that bill.

    7. SpaceX has probably decided that its going to be difficult to meet their cost-reduction goals without being fully reusable, and that even the Falcon Heavy can’t launch the upper-end payloads in fully reusable mode.

    8. Trent,

      I’m with you. Mind you, I’m a big fan of SpaceX, and Tom Mueller and his team in particular. But this seems like an exercise in shark-jumping. I just wish they had a serious competitor for low-cost launch to LEO (ULA and Blue Origin don’t seem to count). It might help them keep their efforts focused on continual improvement in earth-to-LEO costs instead of trying to build the rocket equivalent of the Spruce Goose.

      ~Jon

  6. Good to have new data to work with. My understanding is that MCT was direct (surface to surface) but that can’t possibly be with 100 crew. It could be an easier vehicle to land and take off from the mars surface however (more than enough thrust and wide enough to use mars atmosphere.) So, even though refueling in LEO doesn’t fit Elon’s profile I expect that must be what he intends to do.

    Assuming 300mt for crew and supplies. 50 mt to orbit. That’s a lot of refueling missions although mitigated by whatever a FXX could lift. Would the crew minus supplies be launched all at once with the vehicle to orbit? Would they stay in orbit for perhaps a year while taking on fuel and supplies. They’d need about 1500 mt of fuel.

    Of course, it doesn’t work at all for a more fundamental reason. Elon expects to use a very traditional business approach… sell tickets. That just will not work. He isn’t getting the ticket price down to $500k. He doesn’t consider the cost of a space suit for each colonists. They are not going to go to a world trying to kill them as servants with no resources.

    Whatever he does just makes it easier for a plan that will work… makes ya wonder [dream music cue…]

    1. If the business is large enough the suits can be made in standard sizes and reused. In other words you would rent the suits. There are a lot of possibilities to reduce the mass required for a Mars mission involving ISRU and exploitation of orbital resources. I would not expect them to sell tickets to Mars before them selling tickets to Earth orbit though.

      I think the main deal here is the Raptor engine. The rest is possibilities of future vehicles which may or may not materialize. Tthat they have shown they have the technical ability to make a crossfed stage with 9 tanks based on a module with a single engine. It is a “simple” matter of scaling it up and adapting it to the new fuel since it would be Raptor instead of Merlin powering it.

      1. “they have shown they have the technical ability to make a crossfed stage with 9 tanks based on a module with a single engine.”
        Have they done that? I’m really hoping they get the Falcon Heavy up, but is there any information that they have actually got anything working?

    2. If you are not launching 100 passengers from the surface of earth you would be looking at 15 dragon crew launches. From three pads it would be five flights.. at one flight every two weeks it would take ten weeks .. more likely 12 weeks to assemble the passengers in LEO. Five months to Mars? Could you just do Mars Orbit and then use a ground based reusable for transfering passengers down from Mars orbit?

  7. What are the chances the fairing size for a Falcon Heavy will be larger than the 5.2m listed on Wikipedia?

    1. The standard fairing will probably not change. But just like ULA, if you are willing to pay for the development of a larger fairing for your oversized payload, they would surely consider it.

      But the current fairing should comfortably fit the vast majority of payloads. And that’s another aspect in how they plan to save costs – instead of having multiple fairing sizes like Ariane or ULA.

    2. Gwen already said it was going to be a 7m minimum and more likely 10m .. 33 feet… a stretched faring could go 14 m so about 46′. You could get a bigelow inflatable of about 60′ in diameter I believe R. Bigelow stated. The inside diameter would be about 56′ .
      Using spin calc a 56′ centifuge at 6 rotations a minute or 12 miles per hour would generate .34 g’s.

      So would a sleeping platform and 8 hours a night on this be enough to prevent some of the problems?

      1. My understanding is that long term bed rest has a similar effect to long term weightlessness on bones and muscle. So gravity on the sleeping platform wouldn’t be expected to help much there. But moderate gravity levels in living quarters would help with some problems related to stuff floating around.

  8. If they -did- stick to planning to make money with each individual piece of the puzzle along the way…

    What in the heck are the possibilities for a Falcon X or Falcon X Heavy? I only come up with passengers/tourism, fuel, habitat launches with vague glimmers of space infrasctructure. (Power sats?)

    That’s … a lot of tourists to pay for the rocket.

    1. My guess; the proposed SpaceX SHLV is aimed primarily at commsats and various recon sats. It could launch several at a time. It’d also allow for larger fuel tanks on the commsats (a current limiting factor on their lifespan). This is even more true or reconsats; NRO would love a much higher mass budget to allow for far more orbital maneuvering.

      But, the SHLV only makes sense if it’s an improvement in cost per pound to orbit of other systems (including their own). Otherwise, it makes no sense at all, even for Mars.

      1. Comsats have been switching to ion propulsion. I don’t think they need to be made that much bigger. The main driving force for making them bigger seems, to me, to be a lack of available orbital slots more than anything else.

    2. Elon has said a lot of times that he does not believe power sats make economic sense. If someone paid I bet he wouldn’t mind delivering them to orbit though.

      I think this is more of a case of building the components to enable future infrastructure rather than actually building them. i.e. expect a Falcon 9 and possibly Falcon 9 Heavy equivalent with 1/9th of the engines. Falcon XX seems kind of a stretch. It is probably to be used as a carrot showing SpaceX can service crazy requirements like those in the Constellation program.

      1. I would like to add that someone at SpaceX mentioned previously that the USAF was skittish at the idea of launching a payload on a Falcon 9 Heavy with 27 engines. I can’t remember a vehicle with that many engines actually having a successful launch so it isn’t surprising they are reticent about it. That provided the major push to deliver the bigger engine quicker.

        Remember all those people who said Falcon 9 couldn’t succeed as a launcher because it had too many engines? I was one of the few people who believed they could do it back then. Heck how many engines did the Saturn I first stage have all those years back? People sometimes forget the past too easily.

        I think the 27 engines are probably near the limit of what can be done. More than that and the probabilities of something going wrong get just too big even with modern quality control, automated manufacturing, automated testing, and automated flight control systems.

      2. I think this is more of a case of building the components to enable future infrastructure rather than actually building them. i.e. expect a Falcon 9 and possibly Falcon 9 Heavy equivalent with 1/9th of the engines.

        But a single Raptor powered “F9” would have less capability than a 9x M1D one. And be much harder to reuse. It ain’t happening.

        People in general do not seem to grasp the fundamental paradigm shift that SpaceX is working towards with reusability. And do do that you need to go bigger, not smaller. Can you imagine a fully reusable “FalconX” that can put 50+ mt in LEO? The other launch providers can – but only in their nightmares.

      3. “Elon has said a lot of times that he does not believe power sats make economic sense. If someone paid I bet he wouldn’t mind delivering them to orbit though.”

        Power sats don’t make economic sense.
        But a government could easily create demand for electrical power in space.
        If there was large quantities of water in space, it require
        a significant amount electrical energy to split the water to make rocket fuel.

        EELV are being paid 1 billion dollar per year. End the subsidy, and replace it
        with 1/2 billion dollar per year subsidy which will pays for water test payload
        delivered to orbit which has 95% of the time being in sunlight.
        And allow anyone to have the water, if they split it into rocket fuel.

        If there is enough water, it will create a demand for electrical energy which
        will allow power sats make economic sense.

        This subsidy can serve the same purpose as 1 billion subsidy by providing a
        means of ensuring Military has reliable launch capability.
        Anytime there is problem with a launch, one test a rocket reliability by requiring
        a water test payload, which will be paid for but not much for satellite launch, and
        not the expensive risk of satellite launch.
        So instead requiring SpaceX to have 3 successful launches before being allowed
        to launch military satellites, it could be 3 successful commercial payloads or it can be water payloads.
        And if say SpaceX successful launches but it include one engine failing or some other minor
        problem, one could require that next launch to be water test payload.
        And if have a number planned water test load launches planned, in emergency, one switch
        out the water test payload and put military payload on it- thereby adding to readiness.

  9. I would have to agree that SpaceX should not build the 10m Raptor powered BFR.   It has potential to undo all the success they have had, and it oversteps other capabilities that are needed before Mars colonization can ever occur.   I was initially excited for Mars One, but as the “plan” was unveiled, it looks like a suicide mission that will kill enthusiasm for colonization, as the participants die off from freezing, starving, suffocating, murder, & claustrophobic insanity.   Mars  will execute them with certainty.   No escaping that fate.   No Val Kilmer/Red Planet moment to jump into a convenient Russian sample return rocket, curse at & flip off Mars, and go spend the next 9 months humping the sexy Space babe captain.  I hope nothing like Mars One happens, as it would poison any interest in developing the lacking technology and architectures that need to be developed for a chance at success.  I don’t see how how SpaceX is any closer than Mars one in what it can currently offer or hope to offer any time soon. 

    As has been pointed out by others, there is little to no commercial market for the FX /BFR.   It’s just the means for Elon’s Mars dream.  It commits all of SpaceX’s resources to a path that is not ready to materialize, and it gives competitors a window to overtake them.  I don’t believe ULA, Russia, China & India will just cede commercial space to them.   While SpaceX spends it cash on BFR, I could see competitors develop fuel depots, and catch up on re-use capability.

     I do think developing the Raptor engine has some merits.  I could see it used as the center engine on the existing center core of FH.  The center core is not expected to be capable of return to launch site anyways, so take the better performance on the core, and use less engines overall.  furthermore, everyone seems to take it as a given that reuse ability will work out for SpaceX.  What if it doesn’t?    3 Raptors would then replace 27 Merlins.  It is also a chance for SpaceX to master making high purity methane to alleviate coking  in the Raptor engine.  SpaceX should own methane production, and use the sabatier reaction to make it, as they would have to do on Mars, or any other water available from ISRU.   Control of reactants into the sabatier reaction should give very pure methane.

    I think that before SpaceX has any hope of finding tens of thousands of mars colonists, LEO and lunar excursions will have to pave the way, showing quality of life in space is possible, and develop ECLSS systems can make it reasonably comfortable and safe.   This is another place  SpaceX is vulnerable to its competitors.   Bigelow, the Russians, or the Chinese could end up in the lead for LEO & BEO space habitats that people will trust there lives to.  I thinks Musk and Bezos need to bury the hatchet for a evening and have a serious discussion over unicorn steaks and a nice chianti.   SpaceX lacks a high energy upper stage.  Bezos has a LH2/LOX BE-5 engine that appears similar in thrust to the Merlin’s.  If the ISP is good, and the T/W is favorable, all that might be needed is a vacuum nozzle, and ground support equipment for the LH2 to make the BE-5 a game changer for FH mass to TLI.  SpaceX can then either develop there own architecture for BEO or buy it.  But they have to be able to get it there first.  I think if I was Boeing, I would be making offers to Blue Origin to lock up options on their rocket technology, as they did with XCOR.  This could lock SpaceX into LEO and 6tons to GTO for quite a long time if BFR doesn’t pan out. 

    1. And what do you suppose Mr. Musk is going to do with his smaller launchers when he builds the BFR?

      Throw them away? Your critical thinking skills are less than optimum.

  10. People above are talking about how 3 big engines would be much better than the 27 smaller engines. I certainly can imagine that it would be much cheaper (after the big engine is developed). But don’t the smaller engines have an advantage that your mission can survive a problem with one or several of the engines?

    1. Yes, but having a large number of engines reduces your schedule reliability, because there’s a higher probability of a pre-launch abort (as we’ve seen a couple times with Falcon 9).

    2. Exactly, MikeR. Multiple engines on a booster serve the same purpose of improving overall mission success rates as multiple drives in a RAID storage unit serve in improving overall system reliability/availability – it eliminates a significant single-point failure mode. F9 is already a “RAID-rocket” and so will be FH when it flies. Elon comes from a computing background so I don’t see the application of system reliability engineering principles borrowed from the computing world as any coincidence.

      This design philosophy also greatly helps the system economics by not requiring each engine to be expensively near-perfect. Given the greater complexity of a staged combustion engine like the in-the-works Raptor vs. a simpler design like the Merlin, it should prove more difficult to achieve a comparable level of individual engine reliability. Thus, the fault-tolerance of a multiple engines design for a future SpaceX (or anybody else’s) BFR makes even more sense than it already does for F9/H.

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