Journey Into Mystery (1952) #83

Introducing... the Mighty Thor! The most exciting Super Hero of all time! When the Stone-Men from Saturn invade Earth, only Dr. Donald Blake can stop them -- but he stands no chance, not until he strikes a wooden stick on the ground and finds himself transformed into Thor, God of Thunder! Watch as Thor learns how to wield his hammer in battle! Only this new hero can save the Earth from being conquered!