the 1930s, the most popular films were the low-budget, less-serious, space exploration tales portrayed in the popular, cliff-hanger Saturday matinee serials with the first two science-fiction heroes - Flash Gordon and Buck Rogers.

Flash Gordon: Space Soldiers (1936), the original and the best of its type, with 13 chapters; later condensed into a 97-minute feature film titled Flash Gordon: Rocketship
Flash Gordon's Trip to Mars (1938) - 15 episodes
Flash Gordon Conquers the Universe (1940), 12 episodes, with Carol Hughes as Dale Arden
Popular elements in the swashbuckling films were the perfectly-cast, epic hero athlete/actor Larry "Buster" Crabbe, the lovely heroine and Flash's blonde sweetheart Dale Arden (Jean Rogers), Dr. Hans Zarkov (Frank Shannon), and the malevolent, tyrant Emperor Ming the Merciless (Charles Middleton) on far-off planet Mongo. The Flash Gordon filmswere remade in 1980 (with Sam J. Jones as the title character and Max von Sydow as Ming, with music by Queen), and in 1997 as the animated Flash Gordon: Marooned on Mongo. [There was also a pornographic knock-off film titled Flesh Gordon (1972) that featured a dildo-shaped spaceship.]

Wavy-haired, muscular Buster Crabbe also starred in the 12-part serial Buck Rogers Conquers the Universe (1939) shot between Flash Gordon's Trip to Mars (1938) and Flash Gordon Conquers the Universe (1940). It was derived from the novelette story "Armageddon-2419 A.D." written by Phil Nolan (published in the August 1928 issue of the pulp magazine Amazing Stories), and from the comic strip Buck Rogers in the 25th Century by Dick Calkins. In this sci-fi serial, Buck Rogers pursued the vile Killer