ΔE 16.7, loose: different enough that you should pick on purpose. Bright Green is noticeably lighter, warmer than Space Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Bright Green is noticeably lighter, warmer than Space Green.
The same difference applies the other way round: Space Green is noticeably darker, 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 Space Green on the colour wheel See Bright Green on the colour wheel
All matches: Space Green equivalents · Bright Green equivalents