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A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling)

A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.

deleted 5y ago
[deleted]
ncmncm 5y ago
If you need to refuel, send the fuel where it would be useful to get home with, i.e. where you are really going. Dumping it at Mars does no good. You would then have to stop at Mars to collect it.
- mannerheim 5y ago
  That's assuming you have enough fuel to reach those destinations from Earth, let alone make it from Earth to there with enough payload for a return voyage.
  - ncmncm 5y ago
    I see you are finding this very hard. Try to think it through: If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not Mars. Is this really so difficult? Stop, breathe, and think.
    - mannerheim 5y ago
      > If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.
      - ncmncm 5y ago
        If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again. If your true goal is to have crap on and in orbit around Mars, do that without pretending it has any other value. You don't fool anybody, but you make people wonder about you.
        mannerheim 5y ago
        Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples. Versus, cannibalising several extremely expensive ships in order to get one ship to a destination it's never coming back from. And this is just one example. The lower delta-v from Mars would allow extra payload to the belt, so if anyone ever intend to exploit those resources, starting from Mars will allow them to get heavy equipment there in less time and fewer trips (provided, of course, that they can manufacture that equipment on Mars).
        ncmncm 5y ago
        You start by shipping a million tons of freight to Mars, while I do meaningful stuff at places that are not a waste of time and effort. By the time you are ready to supply fuel FOB at Mars, I have sent a million tons to places worth sending it to, instead. Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing around in puddles everywhere. There is an interior liquid water ocean, and ice lava flows. Seriously, if you need more delta-V for a Jupiter or Saturn trip than spaceship design A gives you, you are much better off making a spaceship design B with enough tankage to make the trip. (Maybe B is just A with an extra tank strapped on; or, a tug boosts A to escape velocity and then loops around Luna and back, aerobraking to LEO.) Park fuel depots at both low and high Earth orbits; you waste nothing by using those, unlike anything parked foolishly at Luna or Mars. Luna, anyway, has stuff that is worth visiting, like craters in permanent shade at the south pole, and lava tubes where vapors have maybe drifted in and froze for hundreds of millions of years. Mars is the armpit of the Solar System.

A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.

deleted 5y ago

[deleted]

ncmncm 5y ago

If you need to refuel, send the fuel where it would be useful to get home with, i.e. where you are really going. Dumping it at Mars does no good. You would then have to stop at Mars to collect it.

mannerheim 5y ago
That's assuming you have enough fuel to reach those destinations from Earth, let alone make it from Earth to there with enough payload for a return voyage.
- ncmncm 5y ago
  I see you are finding this very hard. Try to think it through: If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not Mars. Is this really so difficult? Stop, breathe, and think.
  - mannerheim 5y ago
    > If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.
    - ncmncm 5y ago
      If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again. If your true goal is to have crap on and in orbit around Mars, do that without pretending it has any other value. You don't fool anybody, but you make people wonder about you.
      - mannerheim 5y ago
        Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples. Versus, cannibalising several extremely expensive ships in order to get one ship to a destination it's never coming back from. And this is just one example. The lower delta-v from Mars would allow extra payload to the belt, so if anyone ever intend to exploit those resources, starting from Mars will allow them to get heavy equipment there in less time and fewer trips (provided, of course, that they can manufacture that equipment on Mars).
        ncmncm 5y ago
        You start by shipping a million tons of freight to Mars, while I do meaningful stuff at places that are not a waste of time and effort. By the time you are ready to supply fuel FOB at Mars, I have sent a million tons to places worth sending it to, instead. Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing around in puddles everywhere. There is an interior liquid water ocean, and ice lava flows. Seriously, if you need more delta-V for a Jupiter or Saturn trip than spaceship design A gives you, you are much better off making a spaceship design B with enough tankage to make the trip. (Maybe B is just A with an extra tank strapped on; or, a tug boosts A to escape velocity and then loops around Luna and back, aerobraking to LEO.) Park fuel depots at both low and high Earth orbits; you waste nothing by using those, unlike anything parked foolishly at Luna or Mars. Luna, anyway, has stuff that is worth visiting, like craters in permanent shade at the south pole, and lava tubes where vapors have maybe drifted in and froze for hundreds of millions of years. Mars is the armpit of the Solar System.