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Lunar Starship (if built) could put tens of tons of equipment on the Lunar surface in a fully reusable manner (provided all works out as intended), so even your

Lunar Starship (if built) could put tens of tons of equipment on the Lunar surface in a fully reusable manner (provided all works out as intended), so even your example might actually be duable. Most likely a more mundane setup might be a better first project + due to 1/6 g and no storms to withstand the antennas could likely be much lighter.

giantrobot 6y ago
Starship isn't a very good option. While Starship can lift a lot of mass to LEO in order for it to be reusable it needs to then get it all to the Moon's surface and then take off from the Moon's surface and then get back to Earth. Every gram of fuel is one less gram of payload. So a Starship either needs to carry all of its fuel needed for Lunar take-off and TEI (significantly reducing payload) or refuel on site. Since there's no LOX and Methane deposits on the Moon every Starship Moon landing would need both sent to the Moon ahead of it. Even if you want to assume you can find a bunch of water ice under the regolith you then need to send up a water cracking factory, compressors, and literally tons of solar panels. Then you still don't have any methane. So even if you just have to send methane you've had to build a huge amount of infrastructure out of technology that doesn't exist just to reuse Starships. If you don't reuse Starships you don't get much dollar savings over using Falcons. Starship is designed to use aerobreaking for landing. This is something that's viable on Earth and Mars but useless on the Moon. So any Starship landing on the Moon needs fuel to de-orbit and land, with aerobreaking only the terminal phase of the landing needs fuel. Starship's economics only really work if there's fuel available in LEO, its destination, and its destination has an atmosphere for aerobraking. If those things aren't true it needs to carry all of the fuel needed for its mission from Earth's surface which significantly reduces its payload. Doing shit in space is hard.
- techdragon 6y ago
  Lunar Starship would involve on orbit refuelling and cargo transfer if used as a reusable lunar lander. In case your unfamiliar there’s a specific variant of Starship being proposed (and built?) for landing on the lunar surface it’s designed to avoid problems like having those big raptor engines blast tons of lunar dust around. So using starship to loft the payload into orbit on a reusable launcher, and lunar starship to land it re-usably on the moon is probably one of the only near term practical methods to large scale lunar construction, everyone else keeps throwing away expensive hardware.
  - m4rtink 6y ago
    Indeed! The general idea is that you will have a lunar starship variant that will live in space after initial launch and will be periodicaly refuelled and stocked with cargo in LEO by regular tanker and cargo Starships as needed.
  - giantrobot 6y ago
    Firs the Lunar Starship is not currently being built and has no buyers lined up. Second in-orbit cargo transfer and refueling is not a solved problem. Third Starship is not currently flying and it remains to be seen if it holds up to a fraction of Musk's claims about it. Fourth space construction is far from a solved problem and remote (Lunar far side) construction isn't even a thing, we don't even have large scale remote construction on Earth. Building something like a radio telescope on the Moon is not impossible and doesn't require any unobtanium. It is however pretty far out in terms practicality. Just about zero of the engineering capability required has been demonstrated. Even if my estimates for a Lunar radio telescope were off by an order of magnitude and it would only cost a billion dollars, that's still several FASTs or Arecibos you could build on Earth. The Lunar environment is harsh. Micrometeorites, cosmic rays, and solar flares would wreak havoc on sensitive components of a telescope (radio or otherwise). They're much more of a hazard on the Moon than on Earth because the atmosphere and magnetic field protect the surface. A repair or replacement of a component on a terrestrial instrument might be thousands or millions of dollars. For a Lunar instrument would be at least in the millions. There's a very weird meme going around that because SpaceX exists doing things in space is suddenly simple and cheap. Space is hard. SpaceX et al are making it less expensive but not by huge divisors. A Falcon 9 reusable is only a little cheaper than a Proton-M for similar capability. It's cheaper than ULA rockets by about half. It's a feat for sure but it's not like LEO is suddenly as affordable as air freight.

giantrobot 6y ago

Starship isn't a very good option. While Starship can lift a lot of mass to LEO in order for it to be reusable it needs to then get it all to the Moon's surface and then take off from the Moon's surface and then get back to Earth. Every gram of fuel is one less gram of payload. So a Starship either needs to carry all of its fuel needed for Lunar take-off and TEI (significantly reducing payload) or refuel on site. Since there's no LOX and Methane deposits on the Moon every Starship Moon landing would need both sent to the Moon ahead of it. Even if you want to assume you can find a bunch of water ice under the regolith you then need to send up a water cracking factory, compressors, and literally tons of solar panels. Then you still don't have any methane. So even if you just have to send methane you've had to build a huge amount of infrastructure out of technology that doesn't exist just to reuse Starships. If you don't reuse Starships you don't get much dollar savings over using Falcons. Starship is designed to use aerobreaking for landing. This is something that's viable on Earth and Mars but useless on the Moon. So any Starship landing on the Moon needs fuel to de-orbit and land, with aerobreaking only the terminal phase of the landing needs fuel. Starship's economics only really work if there's fuel available in LEO, its destination, and its destination has an atmosphere for aerobraking. If those things aren't true it needs to carry all of the fuel needed for its mission from Earth's surface which significantly reduces its payload. Doing shit in space is hard.

techdragon 6y ago
Lunar Starship would involve on orbit refuelling and cargo transfer if used as a reusable lunar lander. In case your unfamiliar there’s a specific variant of Starship being proposed (and built?) for landing on the lunar surface it’s designed to avoid problems like having those big raptor engines blast tons of lunar dust around. So using starship to loft the payload into orbit on a reusable launcher, and lunar starship to land it re-usably on the moon is probably one of the only near term practical methods to large scale lunar construction, everyone else keeps throwing away expensive hardware.
- m4rtink 6y ago
  Indeed! The general idea is that you will have a lunar starship variant that will live in space after initial launch and will be periodicaly refuelled and stocked with cargo in LEO by regular tanker and cargo Starships as needed.
- giantrobot 6y ago
  Firs the Lunar Starship is not currently being built and has no buyers lined up. Second in-orbit cargo transfer and refueling is not a solved problem. Third Starship is not currently flying and it remains to be seen if it holds up to a fraction of Musk's claims about it. Fourth space construction is far from a solved problem and remote (Lunar far side) construction isn't even a thing, we don't even have large scale remote construction on Earth. Building something like a radio telescope on the Moon is not impossible and doesn't require any unobtanium. It is however pretty far out in terms practicality. Just about zero of the engineering capability required has been demonstrated. Even if my estimates for a Lunar radio telescope were off by an order of magnitude and it would only cost a billion dollars, that's still several FASTs or Arecibos you could build on Earth. The Lunar environment is harsh. Micrometeorites, cosmic rays, and solar flares would wreak havoc on sensitive components of a telescope (radio or otherwise). They're much more of a hazard on the Moon than on Earth because the atmosphere and magnetic field protect the surface. A repair or replacement of a component on a terrestrial instrument might be thousands or millions of dollars. For a Lunar instrument would be at least in the millions. There's a very weird meme going around that because SpaceX exists doing things in space is suddenly simple and cheap. Space is hard. SpaceX et al are making it less expensive but not by huge divisors. A Falcon 9 reusable is only a little cheaper than a Proton-M for similar capability. It's cheaper than ULA rockets by about half. It's a feat for sure but it's not like LEO is suddenly as affordable as air freight.