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Weight and volume. The air has weight so it'll cost more to launch. The volume would also make them more difficult to launch. Assembling or unfolding in spac

Weight and volume. The air has weight so it'll cost more to launch. The volume would also make them more difficult to launch. Assembling or unfolding in space near earth would allow you to make them larger and inspect them before they leave for venus.

minitoar 6y ago
I could see reusing an empty fuel tank or something as a cute way of doing this.
- ChuckMcM 6y ago
  Oh I like that idea! Tricky to get it through the deceleration phase into the atmosphere but it would have a lot of volume. You would want some way to detach the engines (less mass) after you slowed down while still sealing the tanks.
thaumasiotes 6y ago
> Assembling or unfolding in space near earth would allow you to make them larger and inspect them before they leave for venus. Don't we want them to be rigid spheres?
- tempestn 6y ago
  Yes, but you could still construct it in orbit. Imagine building four quadrants, spooning them together for launch, then fusing ("cold welding") them into a sphere in space.
  - thaumasiotes 6y ago
    It is surely better to construct them here, where we have all our tools, and if really necessary pump them out here. There just isn't an advantage to doing it in space. You end up paying more to create a lower-quality sphere. And what weighs more - the air that got trapped in the sphere when we made it, or the machine we sent up to space to assemble a sphere there?
    - withjive 6y ago
      Seems quite short sighted to assume space manufacturing processes would not improve - or we would not want to improve them. Cold weld it in space, it's not that difficult with some engineering. Space X?
      - thaumasiotes 6y ago
        The assumption is that no matter how much space manufacturing processes improve, ordinary manufacturing processes will improve more than that. This is pretty well guaranteed.
    - tempestn 6y ago
      It's not just the weight that's an issue, but also the volume.

minitoar 6y ago

I could see reusing an empty fuel tank or something as a cute way of doing this.

ChuckMcM 6y ago
Oh I like that idea! Tricky to get it through the deceleration phase into the atmosphere but it would have a lot of volume. You would want some way to detach the engines (less mass) after you slowed down while still sealing the tanks.

thaumasiotes 6y ago

> Assembling or unfolding in space near earth would allow you to make them larger and inspect them before they leave for venus. Don't we want them to be rigid spheres?

tempestn 6y ago
Yes, but you could still construct it in orbit. Imagine building four quadrants, spooning them together for launch, then fusing ("cold welding") them into a sphere in space.
- thaumasiotes 6y ago
  It is surely better to construct them here, where we have all our tools, and if really necessary pump them out here. There just isn't an advantage to doing it in space. You end up paying more to create a lower-quality sphere. And what weighs more - the air that got trapped in the sphere when we made it, or the machine we sent up to space to assemble a sphere there?
  - withjive 6y ago
    Seems quite short sighted to assume space manufacturing processes would not improve - or we would not want to improve them. Cold weld it in space, it's not that difficult with some engineering. Space X?
    - thaumasiotes 6y ago
      The assumption is that no matter how much space manufacturing processes improve, ordinary manufacturing processes will improve more than that. This is pretty well guaranteed.
  - tempestn 6y ago
    It's not just the weight that's an issue, but also the volume.