ΔE 9.3, close: similar, with a visible difference side by side. Saddle Brown is a little darker, more saturated, warmer than Starship Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Saddle Brown is a little darker, more saturated, warmer than Starship Grey.
The same difference applies the other way round: Starship Grey is a little lighter, more muted, cooler.
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.
See Starship Grey on the colour wheel See Saddle Brown on the colour wheel
All matches: Starship Grey equivalents · Saddle Brown equivalents