This is a plot element in Neal Stephenson's The Diamond Age, as well as several other fictional appearances (Edgar Rice Burroughs, Azhar Abidi, Peter Watts, and Iain M. Banks all use the trope).
There are no materials known with sufficient strength to withstand compressive and buckling forces. Not even diamond.
Lightweight stiff structures (honeycomb, something resembling aerogel, perhaps) are other options, but seem unlikely as well.
Gas-filled airships or balloons benefit from the fact that low-density gasses (by either chemical composition or temperature in the case of hot-air balloons) exert a countervailing pressure to balance atmospheric pressure, but with a lower mass, hence providing buoyancy. The internal pressure actually provides some (or much) of the structural rigidity of most airship variants. Any vacuum airship would have to make up for this factor, again, increasing strength (and material mass) requirements.
I am following https://www.o-boot.com/en/ with interest. They claim to have solved the buckling issues by using a roman arch-like structure.
The idea sounds relatively sound to me. One could construct a sphere out of aerogel cones, and the external pressure would reinforce it. Not sure how practical it would be to build such a thing, though.
s/since volume grows slower than volume/since surface area grows slower than volume/
Square-cube law. Mass scales with surface area, lift scales with volume. Large balloons (conventional, not vacuum) are simpler and more efficient than small ones.
As to materials, a tremendous problem with areogels are that they're exceedingly friable. Any friction, flexing, or stress will crumble the gell to a powder. I suspect this is why the gel hasn't taken off as it had been projected to. I did some very-early 1990s work in the space and aerogels were a noted emerging technology thought to have applications in, e.g., mobile home, pre-fab housing, and RV designs. For the most part, fibre-based insulation or expanded-foam (polystyrene) insulation remains the standard, largely because road and other vibration don't reduce your insulation to a few inches of fine dust at the bottom of wall cavities.
Material properties are complex, and represent interesting trade-offs between afforded capabilities and imposed constraints.
https://en.wikipedia.org/wiki/Vacuum_airship
This is a plot element in Neal Stephenson's The Diamond Age, as well as several other fictional appearances (Edgar Rice Burroughs, Azhar Abidi, Peter Watts, and Iain M. Banks all use the trope).
There are no materials known with sufficient strength to withstand compressive and buckling forces. Not even diamond.
Lightweight stiff structures (honeycomb, something resembling aerogel, perhaps) are other options, but seem unlikely as well.
Gas-filled airships or balloons benefit from the fact that low-density gasses (by either chemical composition or temperature in the case of hot-air balloons) exert a countervailing pressure to balance atmospheric pressure, but with a lower mass, hence providing buoyancy. The internal pressure actually provides some (or much) of the structural rigidity of most airship variants. Any vacuum airship would have to make up for this factor, again, increasing strength (and material mass) requirements.