ΔE 15.9, loose: different enough that you should pick on purpose. Starship Steel is noticeably darker, warmer than Blue Steel.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Starship Steel is noticeably darker, warmer than Blue Steel.
The same difference applies the other way round: Blue Steel is noticeably lighter, 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 Blue Steel on the colour wheel See Starship Steel on the colour wheel
All matches: Blue Steel equivalents · Starship Steel equivalents