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> Starting new missions from outside a strong gravity field seems like such a huge advantage. You don’t get to do this, period. All your crew and all your mate

> Starting new missions from outside a strong gravity field seems like such a huge advantage. You don’t get to do this, period. All your crew and all your materials are ultimately coming from Earth (or, in some plans, are mined in-situ). You use considerably more resources getting to your waypoint than you save by leaving from there. Being farther out of the gravity well isn’t entirely positive either; you’re losing out on significant savings from the Oberth effect. Earth-Moon Lagrange points are well past the minimum-cost orbit.

avmich 5y ago
> All your crew and all your materials are ultimately coming from Earth Wait till we start making LOX (and later, I think, metals) on the Moon from regolith. The process is old and tested on Earth, the missing part is actually experimenting with this on the Moon. And as soon as we have more or less robust Earth-Moon transportation, this will become important, as it will significantly simplify near Moon operations. Do you know NASA runs, right now, competitions for e.g. lunar ice extraction and purifying?
ethbr0 5y ago
> All your crew and all your materials are ultimately coming from Earth This is the key state differentiator. If you bring everything from Earth, it doesn't make sense. (So why are we doing it now?) But once you start procuring resources from outside gravity well, things look different.
- Yizahi 5y ago
  Exactly what do you plan to acquire/create outside of Earth, and from where to where do you plan to transfer it realistically? Except for fully autonomous human colonies which will mine stuff nearby and use, almost no transfer of resources in space makes sense, it is way too costly and there is no demand (even imaginary). Since there is no need for that, there is also no need for transfer stations (warehouses) anywhere, be it a planet orbit or Lagrange points.
  - m4rtink 5y ago
    Propelant depots, those make all the difference.
    - zardo 5y ago
      They make sense for an individual mission. Bring up fuel and leave it in the parking orbit. But the optimal parking orbits are going to be different for different destinations, vehicles, and times.
- jandrese 5y ago
  It makes sense if you want to use the rockets you already have instead of building the absolutely titanic rockets you would need to carry everything in one trip. There are metallurgical limits to just how big you can make the rockets as well. But this isn't necessarily advocating for a full time in-orbit refuelling station either. The plan might be to instead launch 2 or 3 rockets, 1 with the stuff and the others with fuel. They meet up in orbit and the fuel rockets refill the stuff rocket so it can go on to Mars or wherever, then they return to Earth for the next mission.

avmich 5y ago

> All your crew and all your materials are ultimately coming from Earth Wait till we start making LOX (and later, I think, metals) on the Moon from regolith. The process is old and tested on Earth, the missing part is actually experimenting with this on the Moon. And as soon as we have more or less robust Earth-Moon transportation, this will become important, as it will significantly simplify near Moon operations. Do you know NASA runs, right now, competitions for e.g. lunar ice extraction and purifying?

ethbr0 5y ago

> All your crew and all your materials are ultimately coming from Earth This is the key state differentiator. If you bring everything from Earth, it doesn't make sense. (So why are we doing it now?) But once you start procuring resources from outside gravity well, things look different.

Yizahi 5y ago
Exactly what do you plan to acquire/create outside of Earth, and from where to where do you plan to transfer it realistically? Except for fully autonomous human colonies which will mine stuff nearby and use, almost no transfer of resources in space makes sense, it is way too costly and there is no demand (even imaginary). Since there is no need for that, there is also no need for transfer stations (warehouses) anywhere, be it a planet orbit or Lagrange points.
- m4rtink 5y ago
  Propelant depots, those make all the difference.
  - zardo 5y ago
    They make sense for an individual mission. Bring up fuel and leave it in the parking orbit. But the optimal parking orbits are going to be different for different destinations, vehicles, and times.
jandrese 5y ago
It makes sense if you want to use the rockets you already have instead of building the absolutely titanic rockets you would need to carry everything in one trip. There are metallurgical limits to just how big you can make the rockets as well. But this isn't necessarily advocating for a full time in-orbit refuelling station either. The plan might be to instead launch 2 or 3 rockets, 1 with the stuff and the others with fuel. They meet up in orbit and the fuel rockets refill the stuff rocket so it can go on to Mars or wherever, then they return to Earth for the next mission.