On the impact on the spaceship relay Mr Musk,
Are the spaceships - do you just add a single
layer of armor/scales?
The defense is in layers, and it isn't about
density of any 'metal' I don't think.
It's tensile strength of nano-woven fabrics,
in many layers - as would reduce the impact
energy of the bullet.
I think if the outer layer was metal,
the 'shape' of it matters more in order
to repel the debris. For instance,
flattened scale vs half a sphere.
If the debris hits a round surface,
energy may dispel as it reflects off the curvature.
And besides that certain 'shaped' outer layer
which is in metal, insides following could
be placed many layers of nano-woven fabrics.
Which would reduce the overall weight of the ship
(therefore more cost-effective)
Less damage, as it bounces back. (Secondary
after-effect of the impact I see on the photo)
and if there is a hollow point that between
the fabric and the actual control systems/living space,
no hardware would be affected from the impact(?)
I don't think we are quite there yet, to
enhance particle fields (like eletromagnetic fields)
with immense energy backup like nuclear
in order to create a barrier --- we are not there yet.
So...... if to be thinking of physical barriers
by material, still would need to follow the rules
here on Earth against impact.