Rocky Jones, Space Cadet was an SF television serial broadcast in 1954. Only 39 episodes were aired, and because the show was shot on film and not aired live, most episodes have survived in reasonable quality. The show was aimed at children but the basic premise would later be echoed in Star Trek -- Rocky was a Space Ranger (an Earth-based space police force), patrolling on behalf of the United Worlds of the Solar System. As it was a serial, most stories were spread out over three episodes, then later re-edited and resold to television as feature-length adventures. We have two such examples here.
In the first movie, Crash of the Moons, two gypsy moons enter the solar system and are going to crash into some of the inhabited worlds. The moons are also inhabited, and Rocky and his sidekick Winky must find a way to save the day. (Look for a guest appearance by John Banner, Sgt. Schultz from Hogan's Heroes.)
In the second, Menace from Outer Space (aka Bobby's Comet), a comet is going to crash in the Earth. Can Rocky and the Space Rangers save the Earth in time? Well, duh!
In look and feel, Rocky Jones is clearly influenced by the old Flash Gordon and Buck Rogers serials featuring Buster Crabbe. The production values might be better, but only marginally. However, there is lots of fun derring-do and action. All the actors take the proceedings seriously enough, but not too much. Except for the bad guys, of course, but in a show like this, that's a good thing.