Fligtht to Mars (1951)

Flight to Mars (1951) is a Cinecolor science fiction film, written for the screen by Arthur Strawn, produced by Walter Mirisch for Monogram Pictures (which also distributed) and directed by Lesley Selander. The film has some similarities to the Russian silent film Aelita. The movie was filmed in five days.
The story involves the arrival on Mars of an American scientific expedition team, who discover an underground-dwelling, dying civilization of Martians. They are anatomically human, and are suspicious of the earthmen's motives, with the majority of the governing body finally deciding to keep the earthmen prisoner. This film reuses almost all the cabin interior details from Rocketship X-M (Lippert Pictures, 1950, and filmed at another studio), except for some of the flight instruments. Even the spaceflight noises are reused. Similarly, the concepts of spaceflight are those postulated in that earlier film. The main differences are this film postulates a planned flight to Mars, whereas the earlier film postulates an accidental flight to Mars, which accident occurs during a planned flight to the Moon. Additionally, this film postulates a Martian species which is in many ways superior to Mankind, and poses a long-term, strategic threat there to, whereas the earlier film postulates a Martian species which is pre-literate, and a throw-back, as a consequence of a global nuclear holocaust which occurred many millennia earlier, and poses only an immediate, tactical threat to the voyagers. - From Wikipedia 

A sequel, Voyage to Venus was proposed but never made

FLIGHT TO MARS
LESLEY SELANDER  (1951)
MONOGRAM PICTURES
72 MIN
USA