ΔE 16.1, loose: different enough that you should pick on purpose. Medium Flesh is noticeably lighter, more muted, cooler than Mars Orange.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Medium Flesh is noticeably lighter, more muted, cooler than Mars Orange.
The same difference applies the other way round: Mars Orange is noticeably darker, more saturated, warmer.
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 Mars Orange on the colour wheel See Medium Flesh on the colour wheel
All matches: Mars Orange equivalents · Medium Flesh equivalents