1940's Mars story: "Star of Blue" by Milton Kaletsky

Thanks to another generous fan of old pulp magazines at the Internet Archive, you can read or download “Star of Blue,” a short story penned by sci-fi writer Milton Kaletsky, as it was originally published in March 1941 issue of Science Fiction magazine.

“Marshall Hughes, leader of Earth's fighting men, finds himself faced with surrender to the heartless ruler of Mars... until he looks into the heavens where the fate of his world rests upon the identification of a color...”