The planet probably got this name due to its red color; Mars is sometimes referred to as 'the Red Planet'.
mars is red because of the dirt on it's surface
( z1 cause :ARG0 ( z2 dirt :location ( z3 surface :part-of ( z4 planet :name ( z5 name :op "Mars" ) ) ) ) :ARG1 ( z6 red :ARG1 z4 ) )