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The 15 launches is a big deal, because it requires either a dozen or so Starship Tanker full stacks, or very-rapid reuse to be fully solved. But it's probably

The 15 launches is a big deal, because it requires either a dozen or so Starship Tanker full stacks, or very-rapid reuse to be fully solved. But it's probably solvable, and otherwise SpaceX can "just" build a dozen Tankers, and reuse them slowly. It's solvable, but personally, I'm not all that optimistic on the timeline though. The shocking thing for me from that video was learning how useless the Lunar Gateway is most of the time due to its near-rectilinear halo orbit. This leads it to be only within range for rescuing those on the moon, for a couple days a week. Why does Gateway have this type of orbit? Because the Senate Launch System doesn't have the delta-v to get the capsule to circularized low-lunar orbit. We designed a moon rocket, which can't get to the moon.

JumpCrisscross 3y ago
> leads it to be only within range for rescuing those on the moon, for a couple days a week I genuinely never heard about the Gateway being there for rescue until Destin's talk. (Not saying he invented it. Just that it wasn't what it was advertised for.) Compared to just landing a spare Earth ascent vehicle, it seems like a stupid way to solve for our lack of low-gravity trauma medicine experience. > Why does Gateway have this type of orbit? Because the Senate Launch System doesn't have the delta-v to get the capsule to circularized low-lunar orbit NRHO also minimises communication black-outs with Earth. With the Gateway in orbit, other craft in circular orbit can maintain continuous contact with the Earth.
- consumer451 3y ago
  He mentions the blackout problem, but having a constellation of a couple relay sats is likely going to happen anyway if IIRC.
  - JumpCrisscross 3y ago
    > having a constellation of a couple relay sats is likely going to happen anyway if IIRC But why would you set that as a pre-requisite? The Gateway is also, as I understand it, a staging ground for testing habitation for a vehicle to Mars.
    - consumer451 3y ago
      > But why would you set that as a pre-requisite? Well, the argument in his video is that there are multi-day gaps in the ability to rescue astronauts off the moon. Balancing that out with a few very small relay satellites, I would pay for a couple Electron launches for the relay, and have a lifeboat capability 24/7. > The Gateway is also, as I understand it, a staging ground for testing habitation for a vehicle to Mars. I have heard that as well, but what I don't understand is how a higher orbit simulates a Mars trip much better. I mean, either way you are not inside a magnetosphere, right? I guess in low-lunar orbit you are more shaded from solar wind by the moon half the time?
      - JumpCrisscross 3y ago
        > the argument in his video is that there are multi-day gaps in the ability to rescue astronauts off the moon Right, which is where he loses me--this is not why we have a Gateway. > Balancing that out with a few very small relay satellites, I would pay for a couple Electron launches for the relay, and have a lifeboat capability 24/7 Building a communications relay constellation isn't a simple task. It's on the roadmap for Artemis. > what I don't understand is how a higher orbit simulates a Mars trip much better The high orbit is irrelevant to this aim. You'd get the same deep-space habitation science from a low, circularised orbit. The high orbit is for creating a one-and-done communication relay.
        consumer451 3y ago
        > Right, which is where he loses me--this is not why we have a Gateway. I am just an everyday armchair astronaut, so please correct me where I'm wrong, but I figured: 1) A lunar lander does not have the delta-v for direct return to earth, from the lunar surface. (or the heat shielding) (2) Part of the Gateway's function is similar to Apollo's Command Module. A place for the lander to dock upon return, and facilitate return to earth. I can see how Gateway differs from Apollo's Command Module, in that it does not return to Earth, but stays in lunar orbit. This does test Mars-like endurance, and is cool. Orion will detach from Gateway, and return independently, right? But why the near-rectilinear halo orbit, which puts the lifeboat capability out reach sometimes? If an astronaut needs something like an appendix removed (random example,) then a few days waiting for Gateway to swing by could make a difference. edit: Oh, near-rectilinear halo orbit also makes it easier for Orion to return to Earth, right? So maybe he said that Orion lacks the delta-v, not SLS. Maybe that helps explain it.
rbanffy 3y ago
> The 15 launches is a big deal, because it requires either a dozen or so Starship Tanker full stacks, It's more a logistics problem than anything else. If a Superheavy and Tanker takes 3 weeks to relaunch, you build 3 to launch weekly and 21 to launch daily. Now you need to have 21 processing facilities and 21 times more people to do that. Launch pads, landing pads, and Mechazillas don't need that long to recover, so you can build just a couple extra ones with each one serving a group of processing facilities.

JumpCrisscross 3y ago

> leads it to be only within range for rescuing those on the moon, for a couple days a week I genuinely never heard about the Gateway being there for rescue until Destin's talk. (Not saying he invented it. Just that it wasn't what it was advertised for.) Compared to just landing a spare Earth ascent vehicle, it seems like a stupid way to solve for our lack of low-gravity trauma medicine experience. > Why does Gateway have this type of orbit? Because the Senate Launch System doesn't have the delta-v to get the capsule to circularized low-lunar orbit NRHO also minimises communication black-outs with Earth. With the Gateway in orbit, other craft in circular orbit can maintain continuous contact with the Earth.

consumer451 3y ago
He mentions the blackout problem, but having a constellation of a couple relay sats is likely going to happen anyway if IIRC.
- JumpCrisscross 3y ago
  > having a constellation of a couple relay sats is likely going to happen anyway if IIRC But why would you set that as a pre-requisite? The Gateway is also, as I understand it, a staging ground for testing habitation for a vehicle to Mars.
  - consumer451 3y ago
    > But why would you set that as a pre-requisite? Well, the argument in his video is that there are multi-day gaps in the ability to rescue astronauts off the moon. Balancing that out with a few very small relay satellites, I would pay for a couple Electron launches for the relay, and have a lifeboat capability 24/7. > The Gateway is also, as I understand it, a staging ground for testing habitation for a vehicle to Mars. I have heard that as well, but what I don't understand is how a higher orbit simulates a Mars trip much better. I mean, either way you are not inside a magnetosphere, right? I guess in low-lunar orbit you are more shaded from solar wind by the moon half the time?
    - JumpCrisscross 3y ago
      > the argument in his video is that there are multi-day gaps in the ability to rescue astronauts off the moon Right, which is where he loses me--this is not why we have a Gateway. > Balancing that out with a few very small relay satellites, I would pay for a couple Electron launches for the relay, and have a lifeboat capability 24/7 Building a communications relay constellation isn't a simple task. It's on the roadmap for Artemis. > what I don't understand is how a higher orbit simulates a Mars trip much better The high orbit is irrelevant to this aim. You'd get the same deep-space habitation science from a low, circularised orbit. The high orbit is for creating a one-and-done communication relay.
      - consumer451 3y ago
        > Right, which is where he loses me--this is not why we have a Gateway. I am just an everyday armchair astronaut, so please correct me where I'm wrong, but I figured: 1) A lunar lander does not have the delta-v for direct return to earth, from the lunar surface. (or the heat shielding) (2) Part of the Gateway's function is similar to Apollo's Command Module. A place for the lander to dock upon return, and facilitate return to earth. I can see how Gateway differs from Apollo's Command Module, in that it does not return to Earth, but stays in lunar orbit. This does test Mars-like endurance, and is cool. Orion will detach from Gateway, and return independently, right? But why the near-rectilinear halo orbit, which puts the lifeboat capability out reach sometimes? If an astronaut needs something like an appendix removed (random example,) then a few days waiting for Gateway to swing by could make a difference. edit: Oh, near-rectilinear halo orbit also makes it easier for Orion to return to Earth, right? So maybe he said that Orion lacks the delta-v, not SLS. Maybe that helps explain it.

rbanffy 3y ago

> The 15 launches is a big deal, because it requires either a dozen or so Starship Tanker full stacks, It's more a logistics problem than anything else. If a Superheavy and Tanker takes 3 weeks to relaunch, you build 3 to launch weekly and 21 to launch daily. Now you need to have 21 processing facilities and 21 times more people to do that. Launch pads, landing pads, and Mechazillas don't need that long to recover, so you can build just a couple extra ones with each one serving a group of processing facilities.