4 ms·

Setting up space based resource extraction needed for that could be too expensive or even effectively impossible without reusable rockets.

jacquesm 4y ago
Which part of a Mars mission requires space based resource extraction?
- moffkalast 4y ago
  The part where you need to get back. It's just atmospheric CO2 to complete the sabatier process though. You could send all the fuel there of course, but that's Apollo levels of throwing money on the bonfire.
  - jacquesm 4y ago
    Compared to the total cost of the mission I highly doubt that that is going to be the thing it hinges on, besides, all you need to be able to do is get back to orbit from Mars, you don't need to lift the fuel to get back to Earth from the Mars surface, you just leave that parked in orbit. Anyway, I don't see it happening at all so debating the execution details of things that are in the realm of the solvable already or at best an optimization isn't going to move the needle, the things that need to be solved that we have no clue about are life support, mental health, exposure to radiation for a prolonged period, waste management. Keep in mind that there is no way to re-supply a mission like that en-route and a crew of say four (which would seem to be a minimum for such a mission, and probably is too low from a redundancy perspective) will eat and drink their way through a small mountain over the course of 4 years+ total mission duration.
    - moffkalast 4y ago
      Believe it or not it's around a 60% reduction in launch mass, so it should cut costs significantly. Tsiolkovsky equation do be like that. https://ntrs.nasa.gov/citations/20140009943 https://ntrs.nasa.gov/citations/20140009943 As for all the human related needs, the ISS has been a decades long study on practically all of those. That's kind of why we have it. Supplying the mission isn't really a fundamental problem since you can send multiple times redundant amounts of all the supplies there on the previous cycle. But yes if something goes wrong they're on their own to solve it for (2 years - time spent there), much like any other mission not in close proximity to Earth. That's why you don't send idiots. And you're right that there's no point in debating it further, because no amount of arguing will stop humans landing on Mars sooner or later.
      - jacquesm 4y ago
        > because no amount of arguing will stop humans landing on Mars sooner or later. One of the points of tfa is that this is unlikely to happen for a variety of other reasons.
- m4rtink 4y ago
  If you don't want it to be expensive as hell - any part. Also with space resources you can make the whole thing quite comfortable - big ship, lots of fuel->deltav->short travel time and lots of shielding for when the Sun decides to reach out and touch you.

jacquesm 4y ago

Which part of a Mars mission requires space based resource extraction?

moffkalast 4y ago
The part where you need to get back. It's just atmospheric CO2 to complete the sabatier process though. You could send all the fuel there of course, but that's Apollo levels of throwing money on the bonfire.
- jacquesm 4y ago
  Compared to the total cost of the mission I highly doubt that that is going to be the thing it hinges on, besides, all you need to be able to do is get back to orbit from Mars, you don't need to lift the fuel to get back to Earth from the Mars surface, you just leave that parked in orbit. Anyway, I don't see it happening at all so debating the execution details of things that are in the realm of the solvable already or at best an optimization isn't going to move the needle, the things that need to be solved that we have no clue about are life support, mental health, exposure to radiation for a prolonged period, waste management. Keep in mind that there is no way to re-supply a mission like that en-route and a crew of say four (which would seem to be a minimum for such a mission, and probably is too low from a redundancy perspective) will eat and drink their way through a small mountain over the course of 4 years+ total mission duration.
  - moffkalast 4y ago
    Believe it or not it's around a 60% reduction in launch mass, so it should cut costs significantly. Tsiolkovsky equation do be like that. https://ntrs.nasa.gov/citations/20140009943 https://ntrs.nasa.gov/citations/20140009943 As for all the human related needs, the ISS has been a decades long study on practically all of those. That's kind of why we have it. Supplying the mission isn't really a fundamental problem since you can send multiple times redundant amounts of all the supplies there on the previous cycle. But yes if something goes wrong they're on their own to solve it for (2 years - time spent there), much like any other mission not in close proximity to Earth. That's why you don't send idiots. And you're right that there's no point in debating it further, because no amount of arguing will stop humans landing on Mars sooner or later.
    - jacquesm 4y ago
      > because no amount of arguing will stop humans landing on Mars sooner or later. One of the points of tfa is that this is unlikely to happen for a variety of other reasons.
m4rtink 4y ago
If you don't want it to be expensive as hell - any part. Also with space resources you can make the whole thing quite comfortable - big ship, lots of fuel->deltav->short travel time and lots of shielding for when the Sun decides to reach out and touch you.