Episodes #133 (according to the leader of the film) of the Daily broadcast of Space Patrol. This would have originally aired in September of 1950, probably.

Identification isn't certain because not very many episodes of this era survive. They're wearing the original uniforms, so it's prior to June of '51. Buzz is there, so it's after May of 50. The ship is called "Terra the fourth" here, though, as opposed to Battle Cruiser 100, which either represents a difference between the writers, or places these episodes sometime in Jan or Feb of 1951 (which is the first time Terra 4 was mentioned in the half hour show.)

Here is episode 134