SpaceX Starship Could Each Make a Dozen Trips to Mars

Elon Musk has said each SpaceX Starship should last for 25-30 years which mean they would be able to make about 12 missions between Earth and Mars.

SpaceX is considering changing the Starship refueling plan. The original plan was to have Starships connect at their tails. The new plan is for Starships to connect side by side.

SOURCES0- Elon Musk, Marcus House
Written by Brian Wang,

47 thoughts on “SpaceX Starship Could Each Make a Dozen Trips to Mars”

  1. Piston technology would be easier to build in the first place, but certainly not to maintain, since it's possible to build turbine compressors with non-contact bearings, that essentially don't wear out at all. So the initial compressors sent from Earth will be turbo, and very long lasting. As long as you keep the filters clean.

    I suppose you would have some interesting options for locally manufactured compressors. Things we'd never try on Earth because they would be surrounded by full atmospheric pressure, not immersed in the 600pa gas they were trying to compress. You're basically talking about a vacuum roughing pump, and those don't normally get installed inside the vacuum chamber.

  2. I agree, though it isn't the quickest to implement option, so it won't be how the first few refueled missions are done.

    I wonder how hard it would be for a Starship to rendezvous with a rotating fuel depot? Just a big tank farm, spinning at a quarter RPM or so, and a truss extending out with plumbing?

    The rotation would settle the fuel, without requiring continuous thrust.

  3. Up until the moment the Moon wants to be independent.

    There's a lot of catching up to do to get to Earth but what if Earth isn't racing ahead?

  4. I'm surprised you don't see more artwork depicting the use of fuel depots.
    Multiple unmanned tanker starships to the fuel depot then just 1 manned mission to full refuel to the fuel depot is the safest option.

  5. Fair point, the fuel factory would have a pretty large flow, so even 2.8% of that flow would be significant. 

    Does anybody compress gasses with reciprocating pistons anymore? (Except small scale, for tires and the like.) I thought that was all turbomachinery, especially at low pressures.

  6. True, but compressing a near-vacuum shouldn't require a lot of energy, just big cylinders and reciprocating pistons, probably with additional compression stages after that.

    And if they're making hundreds of tons of methane fuel from the air, that "trickle" of nitrogen will be tons. 44 tons of CO2 would be mixed with about 1 ton of nitrogen in the air, and produce about 16 tons of methane.

    I don't know how much methane they'll need to make for Starship to get back to Earth, but call it 240 tons of methane, with 15 tons of nitrogen as a side product.

  7. Actually, he is very specific as to needing a "multi-planetary" self sufficient lifeboat. Mere self sufficiency away from Earth is far easier in Space.

  8. Ammonia has always been the forgotten part of the H solution. Many of the troubling things about H are solved with it. Throw in Earth to Earth power beaming and we're done!

  9. "rather than needing multiple starship launches" I was telling an eco guy about the 8 refuel launches and the look of disbelief was so perfect I broke out laughing.

  10. Given the recent success in micr0g O'Neill activity at ISS Lab, it is now perfectly clear that such activity will be forever an enormous part of any technological civilization.To be self-sufficient thus requires such O'Neill In Space Manufacturing facilities. In Mars orbit, for example, if Mars is to be self sufficient. We can make Mars ISM facilities here in Earth orbit, and tow them to Mars orbit! Throw in some Space Solar, sorry, no LSP. Then, if we decide not to go to Mars after all, we will have done useful things for Earth.

  11. Nuclear thermal rockets (NERVA) would allow significant increase in specific impulse while retaining high thrust to weight ratios. Direct nuclear rockets would have even higher specific impulse, but probably substantially lower thrust to weight, but better than ion rockets.

    I think we'll find that, once we're manufacturing them in orbit, in vacuum, we can substantially increase the power to weight ratios of solar panels that no longer have to survive takeoff or exposure to an oxygen atmosphere. This will make ion rockets, or maybe something like VASMIR, powered by solar, look better. But only in the inner solar system.

    I'm also expecting more use of rotovators and momentum exchange tethers. A tether using Phobos as a momentum bank would be ideal for flights to and from Mars, dramatically reducing fuel requirements at that end of the trip.

  12. Hopefully nuclear powered rockets will be the next step. Biggest hurdle is overcoming politics and FUD from the left. With nuclear you still need reaction mass – but it becomes far more efficient with a huge upgrade in energy available. Thus less mass needed to refuel and/or faster trips.

  13. I say that, not because the elements aren't there, but because, being as close to Earth as it is, the Moon will remain dependent on Earth because local production of some items simply won't be economical compared to importing them.

  14. I wonder if it would be possible to keep a booster (or multiple) in orbit. These have much larger tanks than the fueling version of starship and could be used to create a refueling depot. With enough storage, a Starship mission that needs fuel can just launch once and refuel with one stop rather than needing multiple starship launches. Keeping the depot topped up might be logistically easier to manage instead of planning new requirements for each starship mission.

    A mission that recovers the booster engines would allow them to be reused in other starships – maybe keep a couple vacuum engines to allow the depot to be maneuvered to a different orbit as necessary.

  15. Hi Brett. Name one element needed for human survival that we don't know the location of on the Moon?

  16. Mars' atmosphere is a decent vacuum by HS science standards, (600pa) and N2 is only 2.8% of that almost nothing. I suppose the fuel factory will produce a trickle of N2 as a byproduct.

  17. Once they pull the CO2 out of the Mars air, there won't be much left besides nitrogen and argon, so it should be relatively easy to get as much nitrogen as they'll need. No?

  18. Mars needs tankage and floorspace. Over at I read of an ammonia to hydrogen process at UNIST by Gunnar Kim…. Roger Gordon at FuelPositiveCorp can make ammonia cheap with his procedure. So ammonia is a dense way to store high ISP hydrogen, can give Mars nitrogen….cool engines. Ammonia…not methane…is the next big thing.

    Forget Lunar Starship. Forget Mars. I want Starship tankage on Titan…the Chevron world worth the long drive…

  19. ISS can be abandoned in minutes. However, ISS has shown that humans can go months at micr0g, if needed, so it means not only can we go to Mars that way, but we can go far out in rather early design rotating habs and have small micr0g escape pods to get back to safety, taking months perhaps.

  20. Many of the things you mention, and many yet to be discovered, are on their way from ISS micr0g efforts, and their offspring. As these are already underway, they should be able to support the much smaller Mars effort, if people can't figure out that it is economically and practically absurd.

  21. L5 should be the first colony, other than what is needed to get lunar materials to L5, if asteroids are not a better choice. L5, or L4 require a bit less deltaV from earth's surface than low lunar orbit. 3.99 km/s vs 4.04 km/s. The deltav to Mars is a bit less too.
    Earth orbit is way too busy, and should be a transit zone, above the layers of com-sats, up to GEO. Likely tethers, and folder laser beams will be used to transfer momentum, and energy eventually, and that stuff is best done with lots of empty vacuum around.

    People would rest easier if asteroids were coming to L5, rather than earth orbit.

  22. At first the ships would need to re-enter. Eventually, some trips should be made by the interplanetary version. IP version has thinner skin, no flaps, no landing gear, no sea level raptors, ion engine, interplanetary version raptors thrust de-rated lighter ISP enhanced, smaller reaction puck, photovoltaic encrusted skin…..both passenger, and cargo versions without life support.

    Once steel can be made, and aluminum smelted on mars, there will be a huge demand for difficult to manufacture items, like machine tools, bearings, ball screws, motors….. The things you need for the factories that will create a self sufficient industrial base. I guess the first factory after bulk steel, and aluminum forms can be made, is a machine tool factory.

    You need a few lathes, milling machines, and grinders to machine large parts, and things like bearing housings, and shafts for the first generation of mars machine tools. I guess you'd build machine tools until you had enough to use most of the metal output, and then start making all kinds of other large machinery, like steam turbines, compressors, the stuff of heavy industry.
    Bearing factories, and chip fabs should be way down the list of industries to get rolling. It makes much more sense to ship those things from Terra.

  23. But the Moon will likely never be independent/self-sufficient, for that very reason. While the very purpose of Musk's colonization project is to establish a self-sufficient colony.

  24. Technically they could use one or more multiple refuel missions in transit and stretch the alignment window for more repeat trips, it's just not optimal.

  25. As I've said in the past it is all about throughput, throughput, throughput.

    Moon will be settled first because it is closest. Many missions means the amortized cost of each starship per mission is much lower.

    Of course LEO is even closer but lacks ISRU capability.

  26. And the lunar Starship architecture will be different from the Martian and orbital cargo versions, with the landing thrusters at the top to avoid cratering the lunar soil, and the lack of thermal shields for Earth re'entry. Funnily, the lunar version will be very useful outside of the moon too, given there are plenty of airless low gravity bodies out there to land on.

    But I imagine they can return to a kind of single interplanetary architecture, once they have solid landing pads on the Moon and Mars. But that may take some time.

    The first flights to the Moon will be mostly on NASA's dime and I doubt they will prioritize making a landing pad. That will probably be done by SpaceX themselves later.

  27. At one time Musk was talking about sending end of life Starships one way. But maybe that's only for the cargo trips?

    I tend to agree that the initial Starships sent to Mars should stay there. Mars Needs Junkyards!

    Seems an awful expense to take all that useful material to Mars, only to spend more to bring it back. Maybe dismount most of the engines, and occasionally ship them back as cargo?

  28. can we maintain and control (and possibly modify) these things over decades, away from primary shops? – especially gravity-sited shops.

  29. Need we return the Starships home per 1st image? The Mars Musk First Armada seems like a useful asset there, either in parking orbit or surface: cargo, occupied, or depot. Begs the questions about what kind of remote maintenance yard would need to be supported and how.

  30. Round trips to the Moon could be done every 11 days while the Earth-Mars window opens only every 26 months. That's a factor if 70! At that rate, Each Starship could travel to the Moon 840 times in its lifetime.

  31. I guess refueling while thrusting would be feasible for emergency situations. But it seems to me that, if you're going to refuel as many as 8 times per mission, (And be flying many missions requiring refueling.) it might be better to have a modest counter-weight on the end of a tether, and have the ships transfer fuel while hanging from that tether.

    While this requires extra mass, it's reusable extra mass. Which could even be serving some other purpose at the same time.

    As well, an orbital fuel depot would permit refueling flights to be decoupled from missions, the refueling flights would only have to maintain an adequate average pace.

  32. Mars is nitrogen poor, unless reentry constrains cargo capacity, you'd likely be better off bringing the biological wastes with you, as they're already fairly high in nitrogen and other trace nutrients.

    While the Martian colony won't need a perfectly closed life support system, it will certainly need a mostly closed system, and those wastes will help you prime it.

    But, agreed, you don't need much in the way of recycling on the trip, until they start using cyclers.

  33. For long round-trip missions, oxygen and water recycling is likely all that is needed, and that's done reliably on the ISS. Waste and trash can probably be compacted, frozen, and stored outside the ship during transit, and shoved away shortly before aerobraking to burn up in Mars' or Earth's atmosphere.

    A colony will need to better deal with human waste and trash, but they also won't need to be closed systems, as they can collect local air and water.

  34. Maybe they want a single docking method that allows fuel and crew transfer.
    E.g. between an Earth-landing Starship and a Lunar Starship.

  35. Trips to mars look like suicide missions. They need much better life support than what will be on offer to them over the next few decades.

  36. The refueling side by side makes sense, if they only need a few milli-g's to settle the fuel.

    Both Starships can be aligned and thrusting on the same direction, only requiring a pump to move the fuel from one to the other.

    It will require some grapple or lock mechanism, but given the slight forces involved, it shouldn't be beyond the complexity of many other systems they will do.

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