Spaceship Exterior vs Moon Mist Grey

How close are they?

ΔE 6.8, close: similar, with a visible difference side by side. Moon Mist Grey is more saturated than Spaceship Exterior.

Can I use Moon Mist Grey instead of Spaceship Exterior?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Moon Mist Grey is more saturated than Spaceship Exterior.

Can I use Spaceship Exterior instead of Moon Mist Grey?

The same difference applies the other way round: Spaceship Exterior is more muted.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.